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Conventional and alternative concentration processes in milk manufacturing: a comparative study on dairy properties

Abstract

The concentration of dairy products is widely applied in dairy manufacturing due to obtaining products with the high dry matter, added value, reduced volume, and an increase in shelf-life. Traditional thermal concentration processes are the most applied in dairy industries, however, high temperatures can damage the bioactive compounds in milk, in addition to modifying the physicochemical, sensory, and nutritional characteristics of concentrated products. This review summarizes the importance of replacing traditional concentration methods with unconventional non-thermal processes, which can bring an option to dairy industries due to the concentration enabling the preservation of proteins, enzymes, vitamins, color, and flavor of the product. Alternative methods, such as freeze concentration, membrane separation processes, and freeze-drying, compose recent works about new methodologies to concentrate dairy products without changing specific properties and increase the quality, which is one of the main purposes for the dairy industries. Through a comparative study with recent researches, this overview highlights some alternative concentration processes that can improve the yield and increase the quality of concentrated dairy products. With new environmentally sustainable methods and the possibility of reducing the costs of the concentration process, these emerging concentration methods become attractive for dairy industries from a technological and economic perspective.

Keywords:
non-thermal processing; freeze concentration; membrane separation; freeze-drying; dairy processing; thermolabile compounds

1 Introduction

Milk is a highly nutritional valuable food that can be processed, fractionated, and included in dairy products, beverages, or food formulations (Al‐Hilphy et al., 2020Al‐Hilphy, A. R., Ali, H. I., Al‐IEssa, S. A., Lorenzo, J. M., Barba, F. J., & Gavahian, M. (2020). Optimization of process variables on physicochemical properties of milk during an innovative refractance window concentration. Journal of Food Processing and Preservation, 44(10). http://dx.doi.org/10.1111/jfpp.14782.
http://dx.doi.org/10.1111/jfpp.14782...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
; Prestes et al., 2021Prestes, A. A., Verruck, S., Vargas, M. O., Canella, M. H. M., Silva, C. C., Barros, E. L. S., Dantas, A., Oliveira, L. V. A., Maran, B. M., Matos, M., Helm, C. V., & Prudencio, E. S. (2021). Influence of guabiroba pulp (campomanesia xanthocarpa o. berg) added to fermented milk on probiotic survival under in vitro simulated gastrointestinal conditions. Food Research International, 141, 110135. http://dx.doi.org/10.1016/j.foodres.2021.110135. PMid:33642002.
http://dx.doi.org/10.1016/j.foodres.2021...
; Vargas et al., 2021Vargas, M. O., Prestes, A. A., Miotto, M., & Prudêncio, E. S. (2021). Dulce de leche: product types, production processes, quality aspects and innovations minor EDITS. International Journal of Dairy Technology, 74(2), 262-276. http://dx.doi.org/10.1111/1471-0307.12762.
http://dx.doi.org/10.1111/1471-0307.1276...
). In addition, dairy products are elucidated as being excellent sources of nutritional compounds, bring health benefits if introduced in a well-balanced diet (Feeney et al., 2021Feeney, E. L., Lamichhane, P., & Sheehan, J. J. (2021). The cheese matrix: understanding the impact of cheese structure on aspects of cardiovascular health – a food science and a human nutrition perspective. International Journal of Dairy Technology, 74(4), 656-670. http://dx.doi.org/10.1111/1471-0307.12755.
http://dx.doi.org/10.1111/1471-0307.1275...
; Verruck et al., 2019aVerruck, S., Balthazar, C. F., Rocha, R. S., Silva, R., Esmerino, E. A., Pimentel, T. C., Freitas, M. Q., Silva, M. C., Cruz, A. G., & Prudencio, E. S. (2019a). Dairy foods and positive impact on the consumer’s health. In F. Toldrá (Ed.), Advances in food and nutrition research (Vol. 89, pp. 95-164). Cambridge: Elsevier.).

Thermal and non-thermal processes implemented in dairy manufacturing have the main purpose to increase the shelf-life and produce a safe, stable, nutritional, and product (Al‐Hilphy et al., 2020Al‐Hilphy, A. R., Ali, H. I., Al‐IEssa, S. A., Lorenzo, J. M., Barba, F. J., & Gavahian, M. (2020). Optimization of process variables on physicochemical properties of milk during an innovative refractance window concentration. Journal of Food Processing and Preservation, 44(10). http://dx.doi.org/10.1111/jfpp.14782.
http://dx.doi.org/10.1111/jfpp.14782...
; Musina et al., 2018Musina, O., Rashidinejad, A., Putnik, P., Barba, F. J., Abbaspourrad, A., Greiner, R., & Roohinejad, S. (2018). The use of whey protein extract for manufacture of a whipped frozen dairy dessert. Mljekarstvo, 68(4), 254-271. http://dx.doi.org/10.15567/mljekarstvo.2018.0402.
http://dx.doi.org/10.15567/mljekarstvo.2...
; Stratakos et al., 2019Stratakos, A. C., Inguglia, E. S., Linton, M., Tollerton, J., Murphy, L., Corcionivoschi, N., Koidis, A., & Tiwari, B. K. (2019). Effect of high pressure processing on the safety, shelf life and quality of raw milk. Innovative Food Science & Emerging Technologies, 52, 325-333. http://dx.doi.org/10.1016/j.ifset.2019.01.009.
http://dx.doi.org/10.1016/j.ifset.2019.0...
).

Dairy products contain high water content and, with the purpose to expand the shelf-life, concentration processes are fundamental in dairy industries, since the employed technology can improve the efficiency of milk processing, reducing the volume of production and total costs of shipping and storage (Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
). In addition, there is an increase in total dry matter which benefits the added value of a product with high fat and protein content (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Rao, 2018Rao, M. A. (2018). Transport and storage of food products. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 354-394). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-5.
http://dx.doi.org/10.1201/9780429449734-...
; Vargas et al., 2021Vargas, M. O., Prestes, A. A., Miotto, M., & Prudêncio, E. S. (2021). Dulce de leche: product types, production processes, quality aspects and innovations minor EDITS. International Journal of Dairy Technology, 74(2), 262-276. http://dx.doi.org/10.1111/1471-0307.12762.
http://dx.doi.org/10.1111/1471-0307.1276...
).

In large-scale production, traditional concentration methods are the most employed in dairy manufacturing, mainly the evaporation and spray drying processes These unit operations reduce the water content by applying high temperatures during the procedure. However, an intense heat treatment may exceed the heat stability of milk and result in undesired sensory and physiochemical changes, such as separation of milk fat, grittiness, phase separation and sediment formation (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
). Besides, the intense thermal processes may decrease original thermolabile bioactive compounds such as enzymes, vitamins, and proteins (Dumpler et al., 2018Dumpler, J., Peraus, F., Depping, V., Stefánsdóttir, B., Grunow, M., & Kulozik, U. (2018). Modelling of heat stability and heat-induced aggregation of casein micelles in concentrated skim milk using a Weibullian model. International Journal of Dairy Technology, 71(3), 601-612. http://dx.doi.org/10.1111/1471-0307.12501.
http://dx.doi.org/10.1111/1471-0307.1250...
, 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Moejes et al., 2020Moejes, S. N., van Wonderen, G. J., Bitter, J. H., & van Boxtel, A. J. B. (2020). Assessment of air gap membrane distillation for milk concentration. Journal of Membrane Science, 594, 117403. http://dx.doi.org/10.1016/j.memsci.2019.117403.
http://dx.doi.org/10.1016/j.memsci.2019....
).

Emerging non-thermal technologies are promising alternatives that have been developed and explored in dairy manufacturing. With a purpose to decrease the negative effects of the conventional concentration processes and contribute with dairy products with high quality, these alternative procedures preserve sensory and flavor properties and maintain food pigments, original volatile compounds, vitamins, enzymes, and proteins (Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Faion et al., 2019Faion, A. M., Becker, J., Fernandes, I. A., Steffens, J., & Valduga, E. (2019). Sheep’s milk concentration by ultrafiltration and cheese elaboration. Journal of Food Process Engineering, 42(4). http://dx.doi.org/10.1111/jfpe.13058.
http://dx.doi.org/10.1111/jfpe.13058...
; Canella et al., 2020Canella, M. H. M., Dantas, A., Blanco, M., Raventós, M., Hernandez, E., & Prudencio, E. S. (2020). Optimization of goat milk vacuum-assisted block freeze concentration using response surface methodology and NaCl addition influence. LWT, 124, 109133. http://dx.doi.org/10.1016/j.lwt.2020.109133.
http://dx.doi.org/10.1016/j.lwt.2020.109...
; Moejes et al., 2020Moejes, S. N., van Wonderen, G. J., Bitter, J. H., & van Boxtel, A. J. B. (2020). Assessment of air gap membrane distillation for milk concentration. Journal of Membrane Science, 594, 117403. http://dx.doi.org/10.1016/j.memsci.2019.117403.
http://dx.doi.org/10.1016/j.memsci.2019....
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
; Stratakos et al., 2019Stratakos, A. C., Inguglia, E. S., Linton, M., Tollerton, J., Murphy, L., Corcionivoschi, N., Koidis, A., & Tiwari, B. K. (2019). Effect of high pressure processing on the safety, shelf life and quality of raw milk. Innovative Food Science & Emerging Technologies, 52, 325-333. http://dx.doi.org/10.1016/j.ifset.2019.01.009.
http://dx.doi.org/10.1016/j.ifset.2019.0...
). In recent research about milk concentration processes, technologies such as freeze concentration, membrane separation and freeze-drying are efficient, satisfactory and capable to replace traditional concentration processes and develop concentrated dairy products with high quality (Barros et al., 2022aBarros, E. L. S., Silva, C. C., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudencio, E. S. (2022a). Effect of replacement of milk by block freeze concentrated whey in physicochemical and rheological properties of ice cream. Food Science and Technology, 42, e12521. http://dx.doi.org/10.1590/fst.12521.
http://dx.doi.org/10.1590/fst.12521...
; Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
; Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Faion et al., 2019Faion, A. M., Becker, J., Fernandes, I. A., Steffens, J., & Valduga, E. (2019). Sheep’s milk concentration by ultrafiltration and cheese elaboration. Journal of Food Process Engineering, 42(4). http://dx.doi.org/10.1111/jfpe.13058.
http://dx.doi.org/10.1111/jfpe.13058...
; Merkel et al., 2021Merkel, A., Voropaeva, D., & Ondrušek, M. (2021). The impact of integrated nanofiltration and electrodialytic processes on the chemical composition of sweet and acid whey streams. Journal of Food Engineering, 298, 110500. http://dx.doi.org/10.1016/j.jfoodeng.2021.110500.
http://dx.doi.org/10.1016/j.jfoodeng.202...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
; Zhu et al., 2020Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Impact of freeze-drying and subsequent storage on milk metabolites based on 1H NMR and UHPLC-QToF/MS. Food Control, 116, 107017. http://dx.doi.org/10.1016/j.foodcont.2019.107017.
http://dx.doi.org/10.1016/j.foodcont.201...
). Studies can bring essential and attractive information for dairy industries, which can apply different concentration procedures according to the desirable characteristics of their manufacturing processes.

Alternative milk concentration processes have several techniques and different procedures, bringing unique properties to each process. In dairy science and technology, our research group has been operating in the field for over 15 years, with experience in conventional and alternative technologies in milk processing (Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
; Dantas et al., 2021Dantas, A., Quinteros, G. J., Darvishvand, S. Y., Blanco, M., Hernandez, E., Prudencio, E. S., & Samsuri, S. (2021). The combined use of progressive and block freeze concentration in lactose‐free milk: effect of process parameters and influence on the content of carbohydrates and proteins. Journal of Food Process Engineering, 44(11). http://dx.doi.org/10.1111/jfpe.13867.
http://dx.doi.org/10.1111/jfpe.13867...
; Magenis et al., 2006Magenis, R. B., Prudêncio, E. S., Amboni, R. D. M. C., Cerqueira, N. G. Jr., Oliveira, R. V. B., Soldi, V., & Benedet, H. D. (2006). Compositional and physical properties of yogurts manufactured from milk and whey cheese concentrated by ultrafiltration. International Journal of Food Science & Technology, 41(5), 560-568. http://dx.doi.org/10.1111/j.1365-2621.2005.01100.x.
http://dx.doi.org/10.1111/j.1365-2621.20...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
, Muñoz et al., 2019Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263. PMid:30286622.
http://dx.doi.org/10.1177/10820132188032...
; Prudêncio et al., 2014Prudêncio, E. S., Müller, C. M. O., Fritzen-Freire, C. B., Amboni, R. D. M. C., & Petrus, J. C. C. (2014). Effect of whey nanofiltration process combined with diafiltration on the rheological and physicochemical properties of ricotta cheese. Food Research International, 56, 92-99. http://dx.doi.org/10.1016/j.foodres.2013.12.017.
http://dx.doi.org/10.1016/j.foodres.2013...
). The purpose of the group, through this review, is to present an essential background of the main emerging technologies of milk concentration and the benefits caused in the organoleptic properties of dairy products concerning the traditional concentration methods.

2 Conventional concentration processes in milk manufacturing

To produce concentrated or dried dairy products, there are several food processes to remove the liquid fraction, including traditional thermal processes or innovative technologies. The choice will depend on the desired effect of the process on the product’s morphology and the extent of concentration required (Cheng et al., 2018Cheng, F., Zhou, X., & Liu, Y. (2018). Methods for improvement of the thermal efficiency during spray drying. E3S Web of Conferences, 53, 01031. http://dx.doi.org/10.1051/e3sconf/20185301031.
http://dx.doi.org/10.1051/e3sconf/201853...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
). Concentration, drying or the combination of these two technologies are the most energy-intensive operations of the dairy industry and, for this reason, the total costs of these concentration processes must also be considered to apply them on a large-scale (Moejes et al., 2020Moejes, S. N., van Wonderen, G. J., Bitter, J. H., & van Boxtel, A. J. B. (2020). Assessment of air gap membrane distillation for milk concentration. Journal of Membrane Science, 594, 117403. http://dx.doi.org/10.1016/j.memsci.2019.117403.
http://dx.doi.org/10.1016/j.memsci.2019....
; Ramírez et al., 2006Ramírez, C. A., Patel, M., & Blok, K. (2006). From fluid milk to milk powder: energy use and energy efficiency in the European dairy industry. Energy, 31(12), 1984-2004. http://dx.doi.org/10.1016/j.energy.2005.10.014.
http://dx.doi.org/10.1016/j.energy.2005....
).

2.1 Evaporation process

The evaporation of milk has been employed for several years and the main purpose of this unitary operation is to remove the water from the solution to increase the solutes content such as proteins, fat, sugars, and minerals from milk composition. Using high temperatures, the objective is to concentrate on minimum total cost, which is included the energy and cleaning expenditures, capital and operating costs, and product loss (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
). Offering the lowest annual capital cost (approximately € 4M) and high concentration levels, evaporation is considered the most practical concentration approach (Table 1) (Ali et al., 2021Ali, E., Orfi, J., AlAnsary, H., Soukane, S., Elcik, H., Alpatova, A., & Ghaffour, N. (2021). Cost analysis of multiple effect evaporation and membrane distillation hybrid desalination system. Desalination, 517, 115258. http://dx.doi.org/10.1016/j.desal.2021.115258.
http://dx.doi.org/10.1016/j.desal.2021.1...
; Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Schuck et al., 2015Schuck, P., Jeantet, R., Tanguy, G., Méjean, S., Gac, A., Lefebvre, T., Labussière, E., & Martineau, C. (2015). Energy consumption in the processing of dairy and feed powders by evaporation and drying. Drying Technology, 33(2), 176-184. http://dx.doi.org/10.1080/07373937.2014.942913.
http://dx.doi.org/10.1080/07373937.2014....
; Tanguy et al., 2015Tanguy, G., Dolivet, A., Garnier-Lambrouin, F., Méjean, S., Coffey, D., Birks, T., Jeantet, R., & Schuck, P. (2015). Concentration of dairy products using a thin film spinning cone evaporator. Journal of Food Engineering, 166, 356-363. http://dx.doi.org/10.1016/j.jfoodeng.2015.07.001.
http://dx.doi.org/10.1016/j.jfoodeng.201...
).

Table 1
Comparation between the traditional and alternative milk concentration processes.

Usually, the development of evaporators permits the liquid to be concentrated to flow through a tube in which the heat is applied outside. The liquid is heated up to the boiling point at ambient pressure (100 °C at sea level and 85 °C at an altitude approximately 5000 m above sea level) and the water is separated from the concentrated fraction. Due to the high latent heat of water evaporation, the energy efficiency is increased with the employment of multiple stages of evaporators or vapor recycling to reuse energy, and decrease this source demand (Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Ramírez et al., 2006Ramírez, C. A., Patel, M., & Blok, K. (2006). From fluid milk to milk powder: energy use and energy efficiency in the European dairy industry. Energy, 31(12), 1984-2004. http://dx.doi.org/10.1016/j.energy.2005.10.014.
http://dx.doi.org/10.1016/j.energy.2005....
).

In dairy industries, the evaporation process is usually done in long-tube vertical falling film evaporators. In this process, the milk (near at its boiling point) is uniformly fed at the top of the inner surface of a tube, which is built side by side with other tubes, fixed, and enclosed by a jacket (Figure 1A). After the milk passes down inside of each tube, forming a thin film, it boils due to the heat applied by the steam. The concentrated liquid is separated at the bottom part of the equipment and the remaining part is removed from the steam in a subsequent separator. In evaporators with multiple effects, the concentrated liquid is pumped to the next stage, while the steam is used to heat the next stage (Figure 1B)(Fernández-Seara & Pardiñas, 2014Fernández-Seara, J., & Pardiñas, Á. Á. (2014). Refrigerant falling film evaporation review: description, fluid dynamics and heat transfer. Applied Thermal Engineering, 64(1-2), 155-171. http://dx.doi.org/10.1016/j.applthermaleng.2013.11.023.
http://dx.doi.org/10.1016/j.applthermale...
; Guichet & Jouhara, 2020Guichet, V., & Jouhara, H. (2020). Condensation, evaporation and boiling of falling films in wickless heat pipes (two-phase closed thermosyphons): a critical review of correlations. International Journal of Thermofluids, 1-2, 100001. http://dx.doi.org/10.1016/j.ijft.2019.100001.
http://dx.doi.org/10.1016/j.ijft.2019.10...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
).

Figure 1
A: A long tube vertical falling film evaporator. Adapted from Verdurmen & Jong (2003)Verdurmen, R. E. M., & Jong, P. (2003). Optimising product quality and process control for powdered dairy products. In G. Smit (Ed.), Dairy processing (pp. 333-365). Cambridge: Woodhead Publishing. http://dx.doi.org/10.1533/9781855737075.2.333
http://dx.doi.org/10.1533/9781855737075....
; B: Multiple effects of a long tube vertical falling film evaporator.

Falling film evaporators offer the advantage of the short residence time of the liquid within the equipment. In addition, to increase energy efficiency, this process is generally operated under vacuum conditions, which is beneficial for milk concentration, since several bioactive compounds can be damaged by extreme heat exposition (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
). In dairy manufacturing, the evaporation process is used as a first step to concentrate products to drying such as whey protein concentrate, lactose, or powdered milk to increase the stability, reduce the volume and production costs, storage, and transportation. Some products such as condensed milk, dulce de leche, and evaporated milk are sold as concentrated liquids (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Vargas et al., 2021Vargas, M. O., Prestes, A. A., Miotto, M., & Prudêncio, E. S. (2021). Dulce de leche: product types, production processes, quality aspects and innovations minor EDITS. International Journal of Dairy Technology, 74(2), 262-276. http://dx.doi.org/10.1111/1471-0307.12762.
http://dx.doi.org/10.1111/1471-0307.1276...
).

Effects in the dairy matrix composition through the evaporation process

Processing of concentrated dairy products includes several steps that may affect the stability of dairy matrix compounds. Due to the high sensitivity of milk nutritional compounds to intense thermal and mechanical processes, undesirable changes may occur in the physicochemical, sensory, or microbiological characteristics of the dairy matrix and its concentrated products (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Masum et al., 2020Masum, A. K. M., Chandrapala, J., Huppertz, T., Adhikari, B., & Zisu, B. (2020). Influence of drying temperatures and storage parameters on the physicochemical properties of spray-dried infant milk formula powders. International Dairy Journal, 105, 104696. http://dx.doi.org/10.1016/j.idairyj.2020.104696.
http://dx.doi.org/10.1016/j.idairyj.2020...
; Tari et al., 2021Tari, N. R., Gaygadzhiev, Z., Guri, A., & Wright, A. (2021). Effect of pH and heat treatment conditions on physicochemical and acid gelation properties of liquid milk protein concentrate. Journal of Dairy Science, 104(6), 6609-6619. http://dx.doi.org/10.3168/jds.2020-19355. PMid:33773779.
http://dx.doi.org/10.3168/jds.2020-19355...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
; Wu et al., 2021Wu, J., Li, H., A’yun, Q., Doost, A. S., Meulenaer, B., & Van der Meeren, P. (2021). Conjugation of milk proteins and reducing sugars and its potential application in the improvement of the heat stability of (recombined) evaporated milk. Trends in Food Science & Technology, 108, 287-296. http://dx.doi.org/10.1016/j.tifs.2021.01.019.
http://dx.doi.org/10.1016/j.tifs.2021.01...
).

Evaporators must have time and temperature controlled throughout the procedure. Intense heat exposure of the evaporation process affects the natural pH of milk (approximately 6.6-6.8), resulting in changes in the milk salt equilibrium and denaturation proteins during this procedure and a consequently level of coagulation (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Lin et al., 2018Lin, Y., Kelly, A. L., O’Mahony, J. A., & Guinee, T. P. (2018). Effect of heat treatment, evaporation and spray drying during skim milk powder manufacture on the compositional and processing characteristics of reconstituted skim milk and concentrate. International Dairy Journal, 78, 53-64. http://dx.doi.org/10.1016/j.idairyj.2017.10.007.
http://dx.doi.org/10.1016/j.idairyj.2017...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). A significant decrease in pH during heating is primarily due to acid produced from lactose oxidation at high temperatures, hydrolysis of organic phosphate groups, and precipitation of calcium phosphate (Koutina & Skibsted, 2015Koutina, G., & Skibsted, L. H. (2015). Calcium and phosphorus equilibria during acidification of skim milk at elevated temperature. International Dairy Journal, 45, 1-7. http://dx.doi.org/10.1016/j.idairyj.2015.01.006.
http://dx.doi.org/10.1016/j.idairyj.2015...
; Wu et al., 2021Wu, J., Li, H., A’yun, Q., Doost, A. S., Meulenaer, B., & Van der Meeren, P. (2021). Conjugation of milk proteins and reducing sugars and its potential application in the improvement of the heat stability of (recombined) evaporated milk. Trends in Food Science & Technology, 108, 287-296. http://dx.doi.org/10.1016/j.tifs.2021.01.019.
http://dx.doi.org/10.1016/j.tifs.2021.01...
).

Milk proteins directly and indirectly interact with lactose. During any heat treatment, an intense and prolonged heat exposure (above 100 °C) results in the formation of early and, in some dairy products, undesired Maillard products with changes in color, texture and flavor aspects (Dumpler et al., 2018Dumpler, J., Peraus, F., Depping, V., Stefánsdóttir, B., Grunow, M., & Kulozik, U. (2018). Modelling of heat stability and heat-induced aggregation of casein micelles in concentrated skim milk using a Weibullian model. International Journal of Dairy Technology, 71(3), 601-612. http://dx.doi.org/10.1111/1471-0307.12501.
http://dx.doi.org/10.1111/1471-0307.1250...
, 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Dumpler & Kulozik, 2015Dumpler, J., & Kulozik, U. (2015). Heat stability of concentrated skim milk as a function of heating time and temperature on a laboratory scale – improved methodology and kinetic relationship. International Dairy Journal, 49, 111-117. http://dx.doi.org/10.1016/j.idairyj.2015.05.005.
http://dx.doi.org/10.1016/j.idairyj.2015...
, 2016Dumpler, J., & Kulozik, U. (2016). Heat-induced coagulation of concentrated skim milk heated by direct steam injection. International Dairy Journal, 59, 62-71. http://dx.doi.org/10.1016/j.idairyj.2016.03.009.
http://dx.doi.org/10.1016/j.idairyj.2016...
). The consequent isomerization and thermal degradation of lactose are parallel reactions to the Maillard reaction and, products such as formic and acetic acid, from lactose oxidation, also lead to a decrease in pH of milk (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Fox et al., 2015Fox, P. F., Uniacke-Lowe, T., McSweeney, P. L. H., & O’Mahony, J. A. (2015). Dairy chemistry and biochemistry. Cham: Springer International Publishing. Heat-induced changes in milk (pp. 345-375).).

The heat stability and the pH sensitivity of milk are often attributed to the presence of casein micelles formed by calcium bridges and linkages by colloidal calcium phosphate through complex hydrogen, hydrophobic bonds, and electrostatic interactions (Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Koutina & Skibsted, 2015Koutina, G., & Skibsted, L. H. (2015). Calcium and phosphorus equilibria during acidification of skim milk at elevated temperature. International Dairy Journal, 45, 1-7. http://dx.doi.org/10.1016/j.idairyj.2015.01.006.
http://dx.doi.org/10.1016/j.idairyj.2015...
). During a heat processing of milk below 80 °C, whey proteins denature and there are changes in the size and structure of casein micelles, reducing the amount of ionic calcium and phosphate, which will also decrease the pH due to remaining as free ions in the whey fraction for further interactions during acid clot formation (Deeth & Bansal, 2019Deeth, H., & Bansal, N. (2019). Whey proteins: an overview. In H.C. Deeth & N. Bansal (Eds.), Whey proteins: from milk to medicine (pp. 1-50). London: Elsevier. http://dx.doi.org/10.1016/B978-0-12-812124-5.00001-1
http://dx.doi.org/10.1016/B978-0-12-8121...
; Dumpler et al., 2020Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605. PMid:33041027.
http://dx.doi.org/10.3168/jds.2020-18605...
; Koutina & Skibsted, 2015Koutina, G., & Skibsted, L. H. (2015). Calcium and phosphorus equilibria during acidification of skim milk at elevated temperature. International Dairy Journal, 45, 1-7. http://dx.doi.org/10.1016/j.idairyj.2015.01.006.
http://dx.doi.org/10.1016/j.idairyj.2015...
). This consequent coagulum from denaturing whey proteins and casein micelles may result in heat-induced fouling inside of evaporators, increasing the viscosity, decreasing the heat transfer and the energy efficiency of the equipment (Dumpler & Kulozik, 2015Dumpler, J., & Kulozik, U. (2015). Heat stability of concentrated skim milk as a function of heating time and temperature on a laboratory scale – improved methodology and kinetic relationship. International Dairy Journal, 49, 111-117. http://dx.doi.org/10.1016/j.idairyj.2015.05.005.
http://dx.doi.org/10.1016/j.idairyj.2015...
; Wu et al., 2021Wu, J., Li, H., A’yun, Q., Doost, A. S., Meulenaer, B., & Van der Meeren, P. (2021). Conjugation of milk proteins and reducing sugars and its potential application in the improvement of the heat stability of (recombined) evaporated milk. Trends in Food Science & Technology, 108, 287-296. http://dx.doi.org/10.1016/j.tifs.2021.01.019.
http://dx.doi.org/10.1016/j.tifs.2021.01...
). In addition, heat-induced protein accumulation on the inner contact surface of the evaporator can induce the proliferation of microorganisms and problematic decreases in product quality, such as changes in color, flavor, and texture. The growth of pathological microorganisms can also be a risk to the consumer’s health, with the industries being responsible for all the quality and food safety, from processing to the market.

2.2 Spray drying process

Milk powder and powdered dairy products present a globally consolidated market and a particular interest by food industries due to their high acceptability and added value. The milk powder is an interesting solution for those who lack direct access to adequate refrigeration, which characterizes it’s practically of consumption (Ding et al., 2021aDing, H., Wilson, D. I., Yu, W., & Young, B. R. (2021a). An investigation of the relative impact of process and shape factor variables on milk powder quality. Food and Bioproducts Processing, 126, 62-72. http://dx.doi.org/10.1016/j.fbp.2020.12.010.
http://dx.doi.org/10.1016/j.fbp.2020.12....
; Kalyankar et al., 2015Kalyankar, S. D., Deshmukh, M. A., Chopde, S. S., Khedkar, C. D., Lule, V. K., & Deosarkar, S. S. (2015). Milk powder. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 724-728). Burlington: Elsevier.). Due to the functional and nutritional properties of milk and the high value of its components, powdered milk and powdered dairy products are considered a valuable concentrated ingredient for diverse applications in food formulations, such as bakeries, confectionaries, infant formulas, meat products, and nutritional foods (Kalyankar et al., 2015Kalyankar, S. D., Deshmukh, M. A., Chopde, S. S., Khedkar, C. D., Lule, V. K., & Deosarkar, S. S. (2015). Milk powder. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 724-728). Burlington: Elsevier.; Khan et al., 2021Khan, A., Munir, M. T., Yu, W., & Young, B. R. (2021). Near‐infrared spectroscopy and data analysis for predicting milk powder quality attributes. International Journal of Dairy Technology, 74(1), 235-245. http://dx.doi.org/10.1111/1471-0307.12734.
http://dx.doi.org/10.1111/1471-0307.1273...
).

The storage of fresh milk presents obstacles due to the vast volume of dairy processing and the need for refrigerated storage, transport, and marketing. Drying is a conventional way of concentrating food and facilitating logistics, handling milk, increasing the shelf life and stability of the product. The main purpose of converting fresh milk into milk powder is to transform a liquid perishable matrix into a product that can be stored for years without loss in physicochemical, microbiological, nutritional, and sensory quality (Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Ding et al., 2021aDing, H., Wilson, D. I., Yu, W., & Young, B. R. (2021a). An investigation of the relative impact of process and shape factor variables on milk powder quality. Food and Bioproducts Processing, 126, 62-72. http://dx.doi.org/10.1016/j.fbp.2020.12.010.
http://dx.doi.org/10.1016/j.fbp.2020.12....
; Kalyankar et al., 2015Kalyankar, S. D., Deshmukh, M. A., Chopde, S. S., Khedkar, C. D., Lule, V. K., & Deosarkar, S. S. (2015). Milk powder. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 724-728). Burlington: Elsevier.).

The usual process of drying in dairy industries is spray drying and, by definition, is a transformation of feed from a solution, suspension, or paste into a concentrated/dried form by spraying this fluid into a hot drying medium (Verdurmen & Jong, 2003Verdurmen, R. E. M., & Jong, P. (2003). Optimising product quality and process control for powdered dairy products. In G. Smit (Ed.), Dairy processing (pp. 333-365). Cambridge: Woodhead Publishing. http://dx.doi.org/10.1533/9781855737075.2.333
http://dx.doi.org/10.1533/9781855737075....
). To improve the thermal efficiency of the drying procedure and avoid overheating of powder particles, the equipment (spray dryer) can consist of one, two, or three stages (Figure 2). Different from evaporators, there is no recovering of latent heat of the vapor in the spray dryer. Drying is responsible for up to 15% of the industrial energy requirement and, if compared to a concentration by evaporation, the energy demand by the spray drying process is 10-20 times higher per kilogram of water removed (Table 1). Consequently, it is usual to proceed with a primary concentration by evaporation before drying, however, spray-drying is still the most energy-intensive process in dairy industries and has received much attention (Ramírez et al., 2006Ramírez, C. A., Patel, M., & Blok, K. (2006). From fluid milk to milk powder: energy use and energy efficiency in the European dairy industry. Energy, 31(12), 1984-2004. http://dx.doi.org/10.1016/j.energy.2005.10.014.
http://dx.doi.org/10.1016/j.energy.2005....
; Schuck et al., 2015Schuck, P., Jeantet, R., Tanguy, G., Méjean, S., Gac, A., Lefebvre, T., Labussière, E., & Martineau, C. (2015). Energy consumption in the processing of dairy and feed powders by evaporation and drying. Drying Technology, 33(2), 176-184. http://dx.doi.org/10.1080/07373937.2014.942913.
http://dx.doi.org/10.1080/07373937.2014....
; Verdurmen & Jong, 2003Verdurmen, R. E. M., & Jong, P. (2003). Optimising product quality and process control for powdered dairy products. In G. Smit (Ed.), Dairy processing (pp. 333-365). Cambridge: Woodhead Publishing. http://dx.doi.org/10.1533/9781855737075.2.333
http://dx.doi.org/10.1533/9781855737075....
).

Figure 2
Stages of a spray dryer. Adapted from Verdurmen & Jong (2003)Verdurmen, R. E. M., & Jong, P. (2003). Optimising product quality and process control for powdered dairy products. In G. Smit (Ed.), Dairy processing (pp. 333-365). Cambridge: Woodhead Publishing. http://dx.doi.org/10.1533/9781855737075.2.333
http://dx.doi.org/10.1533/9781855737075....
.

In the first stage, the preheated feed solution (< 100 °C) is pumped from a product tank to the atomizing dispositive, which contains the drying chamber. The drying air, composed of filtered atmospheric, is inserted through the hot chamber at 150-250 °C by an air disperser. The atomized feed solution meets the hot drying air and occurs the solvent evaporation, which occurs simultaneously with the cooling of the air. The concentrated product is converted into droplets of 10-200 µm and depending on the dimensions of the spray-dryer, the residence time of the dried particles is around 5 to 30 s (Schuck et al., 2015Schuck, P., Jeantet, R., Tanguy, G., Méjean, S., Gac, A., Lefebvre, T., Labussière, E., & Martineau, C. (2015). Energy consumption in the processing of dairy and feed powders by evaporation and drying. Drying Technology, 33(2), 176-184. http://dx.doi.org/10.1080/07373937.2014.942913.
http://dx.doi.org/10.1080/07373937.2014....
; Verdurmen & Jong, 2003Verdurmen, R. E. M., & Jong, P. (2003). Optimising product quality and process control for powdered dairy products. In G. Smit (Ed.), Dairy processing (pp. 333-365). Cambridge: Woodhead Publishing. http://dx.doi.org/10.1533/9781855737075.2.333
http://dx.doi.org/10.1533/9781855737075....
). Most powder particles fall to the bottom of the dryer and are submitted to a pneumatic transport and an immediate cooling system, which is essential to preserve better flavor, physicochemical characteristics, and long shelf life. The particles with the smallest diameters remain in the air and, if necessary, the air passes to a cyclone to separate the solid fraction. After drying, the powders are transported to the next drying stage or a packing system (Kalyankar et al., 2015Kalyankar, S. D., Deshmukh, M. A., Chopde, S. S., Khedkar, C. D., Lule, V. K., & Deosarkar, S. S. (2015). Milk powder. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 724-728). Burlington: Elsevier.; Masum et al., 2020Masum, A. K. M., Chandrapala, J., Huppertz, T., Adhikari, B., & Zisu, B. (2020). Influence of drying temperatures and storage parameters on the physicochemical properties of spray-dried infant milk formula powders. International Dairy Journal, 105, 104696. http://dx.doi.org/10.1016/j.idairyj.2020.104696.
http://dx.doi.org/10.1016/j.idairyj.2020...
).

Effects in dairy composition through the spray drying process

The dairy concentration by spray drying process is a traditional, important, and economic operation due to the flexibility in handling a variety of products. However, the high temperature needed in this process reduces the heat-sensitive nutritional and sensory components of the original matrix. In addition, the drying air temperature can affect the physicochemical properties of powder milk by changes in the distribution of the majority components, particle morphology, color characteristics, and water activity (Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Habtegebriel et al., 2018Habtegebriel, H., Edward, D., Wawire, M., Sila, D., & Seifu, E. (2018). Effect of operating parameters on the surface and physico-chemical properties of spray-dried camel milk powders. Food and Bioproducts Processing, 112, 137-149. http://dx.doi.org/10.1016/j.fbp.2018.09.010.
http://dx.doi.org/10.1016/j.fbp.2018.09....
; Perusko et al., 2021Perusko, M., Ghnimi, S., Simovic, A., Stevanovic, N., Radomirovic, M., Gharsallaoui, A., Smiljanic, K., Van Haute, S., Stanic-Vucinic, D., & Velickovic, T. C. (2021). Maillard reaction products formation and antioxidative power of spray dried camel milk powders increases with the inlet temperature of drying. LWT, 143, 111091. http://dx.doi.org/10.1016/j.lwt.2021.111091.
http://dx.doi.org/10.1016/j.lwt.2021.111...
).

One of the components of the solid fraction that is most affected during the spray drying process is the milk fat, which is dispersed in a colloidal system with proteins, water, and soluble components. Aromatic compounds of powdered milk undergo several complex changes during processing and, in spray drying conditions precisely, the thermal procedure can cause damage of droplet shrinkage and release free fat, which is easily oxidized and cause sweet taste, fatty and creamy flavor of powdered milk (Feng et al., 2021Feng, D., Wang, J., Ji, X., Min, W., & Yan, W. (2021). HS-GC-IMS detection of volatile organic compounds in yak milk powder processed by different drying methods. LWT, 141, 110855. http://dx.doi.org/10.1016/j.lwt.2021.110855.
http://dx.doi.org/10.1016/j.lwt.2021.110...
). In addition, after drying, the fat is distributed on the surface of whole milk particles and this conformation influences the size of dried flakes and affects the interconnecting among the powder particles, forming an undesirable pasty characteristic (Birchal et al., 2005Birchal, V., Passos, M. L., Wildhagen, G., & Mujumdar, A. (2005). Effect of spray-dryer operating variables on the whole milk powder quality. Drying Technology, 23(3), 611-636. http://dx.doi.org/10.1081/DRT-200054153.
http://dx.doi.org/10.1081/DRT-200054153...
; Habtegebriel et al., 2018Habtegebriel, H., Edward, D., Wawire, M., Sila, D., & Seifu, E. (2018). Effect of operating parameters on the surface and physico-chemical properties of spray-dried camel milk powders. Food and Bioproducts Processing, 112, 137-149. http://dx.doi.org/10.1016/j.fbp.2018.09.010.
http://dx.doi.org/10.1016/j.fbp.2018.09....
; Lin et al., 2018Lin, Y., Kelly, A. L., O’Mahony, J. A., & Guinee, T. P. (2018). Effect of heat treatment, evaporation and spray drying during skim milk powder manufacture on the compositional and processing characteristics of reconstituted skim milk and concentrate. International Dairy Journal, 78, 53-64. http://dx.doi.org/10.1016/j.idairyj.2017.10.007.
http://dx.doi.org/10.1016/j.idairyj.2017...
). Milk protein is also an important macronutrient that can be used as indicator of milk quality after a technological treatment and is also affected by the intense temperature of the spray dryer. According to Vincenzetti et al. (2018)Vincenzetti, S., Cecchi, T., Perinelli, D. R., Pucciarelli, S., Polzonetti, V., Bonacucina, G., Ariani, A., Parrocchia, L., Spera, D. M., Ferretti, E., Vallesi, P., & Polidori, P. (2018). Effects of freeze-drying and spray-drying on donkey milk volatile compounds and whey proteins stability. LWT, 88, 189-195. http://dx.doi.org/10.1016/j.lwt.2017.10.019.
http://dx.doi.org/10.1016/j.lwt.2017.10....
, who studied the effects of spray drying and freeze-drying processes on the β-lactoglobulin and lysozyme content in donkey milk, the high temperature to which the donkey milk was subjected decreased significantly the lysozyme enzymatic activity (58% of residual activity) and β-lactoglobulin content (6.43 mg/mL in fresh milk vs. 5.51 mg/mL in spray-dried milk). The denaturation of milk proteins can also cause encrustations inside the spray-dryer, reducing the efficiency of heat exchange in the equipment and blocking nozzles, causing a low-quality powder and requiring product rework (Bista et al., 2021Bista, A., McCarthy, N., O’Donnell, C. P., & O’Shea, N. (2021). Key parameters and strategies to control milk concentrate viscosity in milk powder manufacture. International Dairy Journal, 121, 105120. http://dx.doi.org/10.1016/j.idairyj.2021.105120.
http://dx.doi.org/10.1016/j.idairyj.2021...
; Cheng et al., 2018Cheng, F., Zhou, X., & Liu, Y. (2018). Methods for improvement of the thermal efficiency during spray drying. E3S Web of Conferences, 53, 01031. http://dx.doi.org/10.1051/e3sconf/20185301031.
http://dx.doi.org/10.1051/e3sconf/201853...
; Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
).

The lactose fraction has also proven to be responsible for important roles in the sensory, nutritional, functional, and physicochemical properties of powdered dairy products (Fialho et al., 2018Fialho, T. L., Martins, E., Silva, C. R. J., Stephani, R., Tavares, G. M., Silveira, A. C. P., Perrone, Í. T., Schuck, P., Oliveira, L. F. C., & Carvalho, A. F. (2018). Lactose-hydrolyzed milk powder: physicochemical and technofunctional characterization. Drying Technology, 36(14), 1688-1695. http://dx.doi.org/10.1080/07373937.2017.1421551.
http://dx.doi.org/10.1080/07373937.2017....
; Park et al., 2016Park, C. W., Stout, M. A., & Drake, M. (2016). The effect of spray-drying parameters on the flavor of nonfat dry milk and milk protein concentrate 70%. Journal of Dairy Science, 99(12), 9598-9610. http://dx.doi.org/10.3168/jds.2016-11692. PMid:27743674.
http://dx.doi.org/10.3168/jds.2016-11692...
; Rongsirikul & Hongsprabhas, 2016Rongsirikul, N., & Hongsprabhas, P. (2016). Brown pigment formation in heated sugar–protein mixed suspensions containing unmodified and peptically modified whey protein concentrates. Journal of Food Science and Technology, 53(1), 800-807. http://dx.doi.org/10.1007/s13197-015-1955-4. PMid:26788001.
http://dx.doi.org/10.1007/s13197-015-195...
; Zhou & Langrish, 2021Zhou, Z., & Langrish, T. (2021). A review of Maillard reactions in spray dryers. Journal of Food Engineering, 305, 110615. http://dx.doi.org/10.1016/j.jfoodeng.2021.110615.
http://dx.doi.org/10.1016/j.jfoodeng.202...
). Depending on the processing conditions, in addition to high temperatures, water evaporation, high concentration of lactose and lysine-rich proteins, Maillard reactions may occur and causes several effects, including the unattractive formation of melanoidins (nitrogen-containing brow pigments), the loss of nutritional value, changes in the sensory properties, presence of off-flavors and formation of potential mutagenic products (Perusko et al., 2021Perusko, M., Ghnimi, S., Simovic, A., Stevanovic, N., Radomirovic, M., Gharsallaoui, A., Smiljanic, K., Van Haute, S., Stanic-Vucinic, D., & Velickovic, T. C. (2021). Maillard reaction products formation and antioxidative power of spray dried camel milk powders increases with the inlet temperature of drying. LWT, 143, 111091. http://dx.doi.org/10.1016/j.lwt.2021.111091.
http://dx.doi.org/10.1016/j.lwt.2021.111...
; Zhou & Langrish, 2021Zhou, Z., & Langrish, T. (2021). A review of Maillard reactions in spray dryers. Journal of Food Engineering, 305, 110615. http://dx.doi.org/10.1016/j.jfoodeng.2021.110615.
http://dx.doi.org/10.1016/j.jfoodeng.202...
). Due to the quick changes in the temperature and moisture composition in the hot chamber of the equipment, Maillard reactions in spray dryers may be different from those liquid systems. Furthermore, due to the fast rate of water removal, the lactose structure is converted into its amorphous glassy state, which is unfavorable to the crystallization phenomenon (Habtegebriel et al., 2018Habtegebriel, H., Edward, D., Wawire, M., Sila, D., & Seifu, E. (2018). Effect of operating parameters on the surface and physico-chemical properties of spray-dried camel milk powders. Food and Bioproducts Processing, 112, 137-149. http://dx.doi.org/10.1016/j.fbp.2018.09.010.
http://dx.doi.org/10.1016/j.fbp.2018.09....
). This lactose form, at high temperatures or moisture content in the storage of powdered dairy products, develops molecular mobility and converts into a rubbery state, which occurs at a temperature range known as glass transition temperature (Tg). If the storage occurs at temperature higher than Tg, the mobility of this lactose conformation increases and the viscosity decreases, initiating the lactose crystallization. According to studies, the extension of Maillard reactions can be reduced by improving the design of spray dryers, as well as the control of dairy concentration processes and all the external variables and internal properties (Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Habtegebriel et al., 2018Habtegebriel, H., Edward, D., Wawire, M., Sila, D., & Seifu, E. (2018). Effect of operating parameters on the surface and physico-chemical properties of spray-dried camel milk powders. Food and Bioproducts Processing, 112, 137-149. http://dx.doi.org/10.1016/j.fbp.2018.09.010.
http://dx.doi.org/10.1016/j.fbp.2018.09....
; Masum et al., 2020Masum, A. K. M., Chandrapala, J., Huppertz, T., Adhikari, B., & Zisu, B. (2020). Influence of drying temperatures and storage parameters on the physicochemical properties of spray-dried infant milk formula powders. International Dairy Journal, 105, 104696. http://dx.doi.org/10.1016/j.idairyj.2020.104696.
http://dx.doi.org/10.1016/j.idairyj.2020...
; Perusko et al., 2021Perusko, M., Ghnimi, S., Simovic, A., Stevanovic, N., Radomirovic, M., Gharsallaoui, A., Smiljanic, K., Van Haute, S., Stanic-Vucinic, D., & Velickovic, T. C. (2021). Maillard reaction products formation and antioxidative power of spray dried camel milk powders increases with the inlet temperature of drying. LWT, 143, 111091. http://dx.doi.org/10.1016/j.lwt.2021.111091.
http://dx.doi.org/10.1016/j.lwt.2021.111...
; Zhou & Langrish, 2021Zhou, Z., & Langrish, T. (2021). A review of Maillard reactions in spray dryers. Journal of Food Engineering, 305, 110615. http://dx.doi.org/10.1016/j.jfoodeng.2021.110615.
http://dx.doi.org/10.1016/j.jfoodeng.202...
).

Due to these undesirable changes in physicochemical and sensory aspects of concentrated dairy products that may occur in traditional concentration processes, evaporation and spray drying can be replaced recently by new and alternative concentration processes from the rise of studies of food engineering and food technology, developing alternative and non-thermal technologies which allow the permanence of highly heat-sensitive milk compounds (Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
; Casas-Forero et al., 2020Casas-Forero, N., Orellana-Palma, P., & Petzold, G. (2020). Influence of block freeze concentration and evaporation on physicochemical properties, bioactive compounds and antioxidant activity in blueberry juice. Food Science and Technology, 40(Suppl. 2), 387-394. http://dx.doi.org/10.1590/fst.29819.
http://dx.doi.org/10.1590/fst.29819...
; Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Petzold et al., 2016Petzold, P. O. G., Orellana, P., Moreno, J. J., Junod, J., & Bugueño, G. (2016). Freeze concentration as a technique to protect valuable heat-labile components of foods. In J. J. Moreno (Ed.), Innovative processing technologies for foods with bioactive compounds (pp. 183-192). Boca Raton: Taylor & Francis Group.; Canella et al., 2020Canella, M. H. M., Dantas, A., Blanco, M., Raventós, M., Hernandez, E., & Prudencio, E. S. (2020). Optimization of goat milk vacuum-assisted block freeze concentration using response surface methodology and NaCl addition influence. LWT, 124, 109133. http://dx.doi.org/10.1016/j.lwt.2020.109133.
http://dx.doi.org/10.1016/j.lwt.2020.109...
; Moejes et al., 2020Moejes, S. N., van Wonderen, G. J., Bitter, J. H., & van Boxtel, A. J. B. (2020). Assessment of air gap membrane distillation for milk concentration. Journal of Membrane Science, 594, 117403. http://dx.doi.org/10.1016/j.memsci.2019.117403.
http://dx.doi.org/10.1016/j.memsci.2019....
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
). Recently, the dairy sector around the world aims for product quality. Dairy products with high functional and nutritional quality have become the most desired option for consumers, being one of the main focuses of manufacturing. Studies, researches, and development of new food concentration processes allow new choices for industries, improving the production chain.

3 Alternative concentration processes in milk manufacturing

Non-conventional concentration processes gain increasingly attention from dairy industries as means to decrease the negative effects of conventional processing technologies. Non-thermal technologies maintain the maximum of milk bioactive compounds, obtaining a concentrated dairy product with high quality, nutritional and functional value, accepted sensorially and offsetting the total production costs. The advances of new studies support industries to apply emergent technologies in the dairy manufacturing according to the production flow, method of operation and the type of dairy products, since alternative technologies develop products with specific properties to each type of method, which also becomes a factor of choice for the industrial sector on large-scale application (Barros et al., 2022aBarros, E. L. S., Silva, C. C., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudencio, E. S. (2022a). Effect of replacement of milk by block freeze concentrated whey in physicochemical and rheological properties of ice cream. Food Science and Technology, 42, e12521. http://dx.doi.org/10.1590/fst.12521.
http://dx.doi.org/10.1590/fst.12521...
; Camelo-Silva et al., 2022bCamelo-Silva, C., Barros, E. L. S., Verruck, S., Maran, B. M., Canella, M. H. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). How ice cream manufactured with concentrated milk serves as a protective probiotic carrier? An in vitro gastrointestinal assay. Food Science and Technology, 42, e28621. http://dx.doi.org/10.1590/fst.28621.
http://dx.doi.org/10.1590/fst.28621...
; Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; France et al., 2021France, T. C., Bot, F., Kelly, A. L., Crowley, S. V., & O’Mahony, J. A. (2021). The influence of temperature on filtration performance and fouling during cold microfiltration of skim milk. Separation and Purification Technology, 262, 118256. http://dx.doi.org/10.1016/j.seppur.2020.118256.
http://dx.doi.org/10.1016/j.seppur.2020....
; Canella et al., 2020Canella, M. H. M., Dantas, A., Blanco, M., Raventós, M., Hernandez, E., & Prudencio, E. S. (2020). Optimization of goat milk vacuum-assisted block freeze concentration using response surface methodology and NaCl addition influence. LWT, 124, 109133. http://dx.doi.org/10.1016/j.lwt.2020.109133.
http://dx.doi.org/10.1016/j.lwt.2020.109...
; Merkel et al., 2021Merkel, A., Voropaeva, D., & Ondrušek, M. (2021). The impact of integrated nanofiltration and electrodialytic processes on the chemical composition of sweet and acid whey streams. Journal of Food Engineering, 298, 110500. http://dx.doi.org/10.1016/j.jfoodeng.2021.110500.
http://dx.doi.org/10.1016/j.jfoodeng.202...
; Shabbir et al., 2021Shabbir, M. A., Ahmed, H., Maan, A. A., Rehman, A., Afraz, M. T., Iqbal, M. W., Khan, I. M., Amir, R. M., Ashraf, W., Khan, M. R., & Aadil, R. M. (2021). Effect of non-thermal processing techniques on pathogenic and spoilage microorganisms of milk and milk products. Food Science and Technology, 41(2), 279-294. http://dx.doi.org/10.1590/fst.05820.
http://dx.doi.org/10.1590/fst.05820...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
).

3.1 Freeze concentration

The freeze concentration process is a non-thermal concentration technology applied in liquid foods based on a solid-liquid separation at low temperatures, which the water fraction is frozen, transformed into pure ice crystals, and removed from the concentrated solution (Ding et al., 2021bDing, Z., Qin, F. G. F., Peng, K., Yuan, J., Huang, S., Jiang, R., & Shao, Y. (2021b). Heat and mass transfer of scraped surface heat exchanger used for suspension freeze concentration. Journal of Food Engineering, 288, 110141. http://dx.doi.org/10.1016/j.jfoodeng.2020.110141.
http://dx.doi.org/10.1016/j.jfoodeng.202...
; Sánchez et al., 2010Sánchez, J., Ruiz, Y., Raventós, M., Auleda, J. M., & Hernández, E. (2010). Progressive freeze concentration of orange juice in a pilot plant falling film. Innovative Food Science & Emerging Technologies, 11(4), 644-651. http://dx.doi.org/10.1016/j.ifset.2010.06.006.
http://dx.doi.org/10.1016/j.ifset.2010.0...
). This method can be used to concentrate or pre-concentrate heat-sensitive compounds, which is an interesting alternative for dairy manufacturing, due to the maintenance of the nutritional value, volatile compounds, and flavor of dairy products (Barros et al., 2022bBarros, E. L. S., Silva, C. C., Verruck, S., Canella, M. H. M., Maran, B. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). Concentrated whey from block freeze concentration or milk-based ice creams on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. Food Science and Technology, 42, e84021. http://dx.doi.org/10.1590/fst.84021.
http://dx.doi.org/10.1590/fst.84021...
; Benedetti et al., 2015Benedetti, S., Prudêncio, E. S., Nunes, G. L., Guizoni, K., Fogaça, L. A., & Petrus, J. C. C. (2015). Antioxidant properties of tofu whey concentrate by freeze concentration and nanofiltration processes. Journal of Food Engineering, 160, 49-55. http://dx.doi.org/10.1016/j.jfoodeng.2015.03.021.
http://dx.doi.org/10.1016/j.jfoodeng.201...
; Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
; Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Canella et al., 2020Canella, M. H. M., Dantas, A., Blanco, M., Raventós, M., Hernandez, E., & Prudencio, E. S. (2020). Optimization of goat milk vacuum-assisted block freeze concentration using response surface methodology and NaCl addition influence. LWT, 124, 109133. http://dx.doi.org/10.1016/j.lwt.2020.109133.
http://dx.doi.org/10.1016/j.lwt.2020.109...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
; Prestes et al., 2022Prestes, A. A., Helm, C. V., Esmerino, E. A., Silva, R., Cruz, A. G., & Prudencio, E. S. (2022). Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: a review. Journal of Food Science, 87(2), 488-502. http://dx.doi.org/10.1111/1750-3841.16027. PMid:35049054.
http://dx.doi.org/10.1111/1750-3841.1602...
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
). Freeze concentrated dairy products can be used in diverse food formulations or as an intermediate matrix in dairy processing (Balde & Aider, 2016Balde, A., & Aider, M. (2016). Impact of cryoconcentration on casein micelle size distribution, micelles inter-distance, and flow behavior of skim milk during refrigerated storage. Innovative Food Science & Emerging Technologies, 34, 68-76. http://dx.doi.org/10.1016/j.ifset.2015.12.032.
http://dx.doi.org/10.1016/j.ifset.2015.1...
; Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Barros et al., 2022bBarros, E. L. S., Silva, C. C., Verruck, S., Canella, M. H. M., Maran, B. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). Concentrated whey from block freeze concentration or milk-based ice creams on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. Food Science and Technology, 42, e84021. http://dx.doi.org/10.1590/fst.84021.
http://dx.doi.org/10.1590/fst.84021...
; Camelo-Silva et al., 2022bCamelo-Silva, C., Barros, E. L. S., Verruck, S., Maran, B. M., Canella, M. H. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). How ice cream manufactured with concentrated milk serves as a protective probiotic carrier? An in vitro gastrointestinal assay. Food Science and Technology, 42, e28621. http://dx.doi.org/10.1590/fst.28621.
http://dx.doi.org/10.1590/fst.28621...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
).

The process is based on lowering and controlling the temperature of the solution below its freezing point to avoid freezing all the components simultaneously, at the eutectic point. The purity of ice crystals increases with controlled freezing above the eutectic point of the solution, preserving all the properties of the original liquid matrix. Usually, the upper limit of freeze concentration, concerning the original liquid food, range from 40 to 50% of solid content, depending on the level of soluble solids and the food matrix composition (Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Prestes et al., 2022Prestes, A. A., Helm, C. V., Esmerino, E. A., Silva, R., Cruz, A. G., & Prudencio, E. S. (2022). Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: a review. Journal of Food Science, 87(2), 488-502. http://dx.doi.org/10.1111/1750-3841.16027. PMid:35049054.
http://dx.doi.org/10.1111/1750-3841.1602...
; Sánchez et al., 2011bSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011b). Freeze concentration of whey in a falling-film based pilot plant: process and characterization. Journal of Food Engineering, 103(2), 147-155. http://dx.doi.org/10.1016/j.jfoodeng.2010.10.009.
http://dx.doi.org/10.1016/j.jfoodeng.201...
).

Since this process does not involve a liquid-vapor interface, there is the maximum preservation of thermolabile compounds, increasing the quality of the concentrated product. In addition, from a thermodynamic point of view, the freeze concentration is highly interesting due the energy consumption is lower when compared to evaporation and spray drying processes. The latent heat of water freezing is almost one-seventh of latent heat of water evaporation (335 kJ.kg-1 vs 2260 kJ.kg-1), which is a potential for energy saving for de-watering of liquid foods (Table 1) (Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Casas-Forero et al., 2020Casas-Forero, N., Orellana-Palma, P., & Petzold, G. (2020). Influence of block freeze concentration and evaporation on physicochemical properties, bioactive compounds and antioxidant activity in blueberry juice. Food Science and Technology, 40(Suppl. 2), 387-394. http://dx.doi.org/10.1590/fst.29819.
http://dx.doi.org/10.1590/fst.29819...
; Ding et al., 2021bDing, Z., Qin, F. G. F., Peng, K., Yuan, J., Huang, S., Jiang, R., & Shao, Y. (2021b). Heat and mass transfer of scraped surface heat exchanger used for suspension freeze concentration. Journal of Food Engineering, 288, 110141. http://dx.doi.org/10.1016/j.jfoodeng.2020.110141.
http://dx.doi.org/10.1016/j.jfoodeng.202...
; Prestes et al., 2022Prestes, A. A., Helm, C. V., Esmerino, E. A., Silva, R., Cruz, A. G., & Prudencio, E. S. (2022). Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: a review. Journal of Food Science, 87(2), 488-502. http://dx.doi.org/10.1111/1750-3841.16027. PMid:35049054.
http://dx.doi.org/10.1111/1750-3841.1602...
). In freeze concentration methods, the energy savings can also be related to the possibility of using passive thawing as a recovery step of the concentrated phase, which enhances the energy efficiency and quality of the concentrated products (Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
). Since the yield of the concentrate is not high compared to other concentration methods, the separation of frozen water from the concentrate solution can be carried out once or through several successive freezing steps, in the same liquid food. This procedure, which increases the soluble solids content, will depend on the original composition of the liquid matrix, the desirable objective, and the yield of each freeze concentration stage. In the freeze concentration technology, ice crystals can be formed from liquid solutions in different methods: suspension, progressive, and block freeze concentration, with distinct freeze techniques and ice crystals separation (Casas-Forero et al., 2020Casas-Forero, N., Orellana-Palma, P., & Petzold, G. (2020). Influence of block freeze concentration and evaporation on physicochemical properties, bioactive compounds and antioxidant activity in blueberry juice. Food Science and Technology, 40(Suppl. 2), 387-394. http://dx.doi.org/10.1590/fst.29819.
http://dx.doi.org/10.1590/fst.29819...
; Ding et al., 2021bDing, Z., Qin, F. G. F., Peng, K., Yuan, J., Huang, S., Jiang, R., & Shao, Y. (2021b). Heat and mass transfer of scraped surface heat exchanger used for suspension freeze concentration. Journal of Food Engineering, 288, 110141. http://dx.doi.org/10.1016/j.jfoodeng.2020.110141.
http://dx.doi.org/10.1016/j.jfoodeng.202...
; Samsuri et al., 2018Samsuri, S., Amran, N. A., & Jusoh, M. (2018). Modelling of heat transfer for progressive freeze concentration process by spiral finned crystallizer. Chinese Journal of Chemical Engineering, 26(5), 970-975. http://dx.doi.org/10.1016/j.cjche.2017.09.025.
http://dx.doi.org/10.1016/j.cjche.2017.0...
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
,2011bSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011b). Freeze concentration of whey in a falling-film based pilot plant: process and characterization. Journal of Food Engineering, 103(2), 147-155. http://dx.doi.org/10.1016/j.jfoodeng.2010.10.009.
http://dx.doi.org/10.1016/j.jfoodeng.201...
; Zambrano et al., 2018Zambrano, A., Ruiz, Y., Hernández, E., Raventós, M., & Moreno, F. L. (2018). Freeze desalination by the integration of falling film and block freeze-concentration techniques. Desalination, 436, 56-62. http://dx.doi.org/10.1016/j.desal.2018.02.015.
http://dx.doi.org/10.1016/j.desal.2018.0...
).

The suspension freeze concentration is the most complex and expansive method of freeze concentration, based on the formation of individual ice crystals when the liquid matrix is submitted at low temperatures. An initial phase of crystallization occurs and the ice crystals position themselves into large ice particles, increasing the volume and, in the second phase, ice nuclei grow inside the solution (Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
). The size of these ice crystals is limited, and the separation of the concentrate is complex with the use of typical equipment, with specific purposes (Figure 3A). The system is composed of a crystallizer (heat exchanger) to promote the crystals’ growth. At a pre-freezing temperature, the liquid matrix is cooled and advances to the crystallizer to form ice crystals, which are removed from the concentrate fraction inside of a separator. The remains of frozen pure water are separated from the concentrated liquid in a wash column with compression to handle the ice crystals with high purity (Aider & Halleux, 2009Aider, M., & Halleux, D. (2009). Cryoconcentration technology in the bio-food industry: principles and applications. Lebensmittel-Wissenschaft + Technologie, 42(3), 679-685. http://dx.doi.org/10.1016/j.lwt.2008.08.013.
http://dx.doi.org/10.1016/j.lwt.2008.08....
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
).

Figure 3
A: Suspension freeze concentration scheme. Adapted from Aider & Halleux (2009)Aider, M., & Halleux, D. (2009). Cryoconcentration technology in the bio-food industry: principles and applications. Lebensmittel-Wissenschaft + Technologie, 42(3), 679-685. http://dx.doi.org/10.1016/j.lwt.2008.08.013.
http://dx.doi.org/10.1016/j.lwt.2008.08....
and Prestes et al. (2022)Prestes, A. A., Helm, C. V., Esmerino, E. A., Silva, R., Cruz, A. G., & Prudencio, E. S. (2022). Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: a review. Journal of Food Science, 87(2), 488-502. http://dx.doi.org/10.1111/1750-3841.16027. PMid:35049054.
http://dx.doi.org/10.1111/1750-3841.1602...
; B: Vertical progressive freeze concentration scheme. Adapted from Muñoz et al. (2019)Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263. PMid:30286622.
http://dx.doi.org/10.1177/10820132188032...
; C: Block freeze concentration system.

The progressive freeze concentration is one of the most important methods for concentrating liquid foods and is based on the layer crystallization, in which a large mass of ice is formed on a cold surface, with an easier separation due to the ice crystals adhering to the surface (Moharramzadeh et al., 2021Moharramzadeh, S., Ong, S. K., Alleman, J., & Cetin, K. S. (2021). Parametric study of the progressive freeze concentration for desalination. Desalination, 510, 115077. http://dx.doi.org/10.1016/j.desal.2021.115077.
http://dx.doi.org/10.1016/j.desal.2021.1...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Samsuri et al., 2018Samsuri, S., Amran, N. A., & Jusoh, M. (2018). Modelling of heat transfer for progressive freeze concentration process by spiral finned crystallizer. Chinese Journal of Chemical Engineering, 26(5), 970-975. http://dx.doi.org/10.1016/j.cjche.2017.09.025.
http://dx.doi.org/10.1016/j.cjche.2017.0...
). This process is simpler and must be developed according to specific properties of the liquid food, the concentrate fraction, and its yield at the end of the procedure. The costs of operation, equipment, and maintenance are low, which makes this process promising to be applied on a large scale and replace the complexity of a concentration by suspension crystallization (Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
). This type of freeze concentration has been proven to be efficient in studies about the separation and concentration of dairy products, which systems were developed and improved according to the dairy matrix and specific needs (Chabarov & Aider, 2014Chabarov, A., & Aider, M. (2014). Mathematical modeling and experimental validation of the mass transfer during unidirectional progressive cryoconcentration of skim milk. Innovative Food Science & Emerging Technologies, 21, 151-159. http://dx.doi.org/10.1016/j.ifset.2013.08.001.
http://dx.doi.org/10.1016/j.ifset.2013.0...
; Dantas et al., 2021Dantas, A., Quinteros, G. J., Darvishvand, S. Y., Blanco, M., Hernandez, E., Prudencio, E. S., & Samsuri, S. (2021). The combined use of progressive and block freeze concentration in lactose‐free milk: effect of process parameters and influence on the content of carbohydrates and proteins. Journal of Food Process Engineering, 44(11). http://dx.doi.org/10.1111/jfpe.13867.
http://dx.doi.org/10.1111/jfpe.13867...
; Muñoz et al., 2019Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263. PMid:30286622.
http://dx.doi.org/10.1177/10820132188032...
; Samsuri et al., 2018Samsuri, S., Amran, N. A., & Jusoh, M. (2018). Modelling of heat transfer for progressive freeze concentration process by spiral finned crystallizer. Chinese Journal of Chemical Engineering, 26(5), 970-975. http://dx.doi.org/10.1016/j.cjche.2017.09.025.
http://dx.doi.org/10.1016/j.cjche.2017.0...
). A progressive freeze concentration system was proposed for the first time in the separation of skimmed milk by Muñoz et al. (2019)Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263. PMid:30286622.
http://dx.doi.org/10.1177/10820132188032...
, proving to be an effective method to concentrate milk and offering interesting energy savings, when compared to the suspension method and nutritional preservation of the concentrated skimmed milk. In this experimental vertical system, the liquid matrix is placed in an agitated tank with a cooling jacket. The low temperature causes the formation of an ice layer on the cooling walls of the tank and a mechanical stirring is applied to decrease the solute accumulation in the ice fraction (Figure 3B) (Ojeda et al., 2017Ojeda, A., Moreno, F. L., Ruiz, R. Y., Blanco, M., Raventós, M., & Hernández, E. (2017). Effect of process parameters on the progressive freeze concentration of sucrose solutions. Chemical Engineering Communications, 204(8), 951-956. http://dx.doi.org/10.1080/00986445.2017.1328413.
http://dx.doi.org/10.1080/00986445.2017....
).

In the block freeze concentration technique, the liquid food is frozen and partially thawed by the assisted gravitational defrost method to separate ice and concentrate fractions (Zambrano et al., 2018Zambrano, A., Ruiz, Y., Hernández, E., Raventós, M., & Moreno, F. L. (2018). Freeze desalination by the integration of falling film and block freeze-concentration techniques. Desalination, 436, 56-62. http://dx.doi.org/10.1016/j.desal.2018.02.015.
http://dx.doi.org/10.1016/j.desal.2018.0...
). At a controlled temperature, the ice block performs as a solid carcase and, by the phenomenon of diffusion, the concentrate is drained (Aider & Halleux, 2009Aider, M., & Halleux, D. (2009). Cryoconcentration technology in the bio-food industry: principles and applications. Lebensmittel-Wissenschaft + Technologie, 42(3), 679-685. http://dx.doi.org/10.1016/j.lwt.2008.08.013.
http://dx.doi.org/10.1016/j.lwt.2008.08....
) (Figure 3C). About all the freeze concentration methods, this technique is promising due the facility of operation, simpler equipment and the lower total cost, with diverse applications and studies in the dairy sector (Aider & Halleux, 2009Aider, M., & Halleux, D. (2009). Cryoconcentration technology in the bio-food industry: principles and applications. Lebensmittel-Wissenschaft + Technologie, 42(3), 679-685. http://dx.doi.org/10.1016/j.lwt.2008.08.013.
http://dx.doi.org/10.1016/j.lwt.2008.08....
; Barros et al., 2022aBarros, E. L. S., Silva, C. C., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudencio, E. S. (2022a). Effect of replacement of milk by block freeze concentrated whey in physicochemical and rheological properties of ice cream. Food Science and Technology, 42, e12521. http://dx.doi.org/10.1590/fst.12521.
http://dx.doi.org/10.1590/fst.12521...
; Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
; Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Canella et al., 2020Canella, M. H. M., Dantas, A., Blanco, M., Raventós, M., Hernandez, E., & Prudencio, E. S. (2020). Optimization of goat milk vacuum-assisted block freeze concentration using response surface methodology and NaCl addition influence. LWT, 124, 109133. http://dx.doi.org/10.1016/j.lwt.2020.109133.
http://dx.doi.org/10.1016/j.lwt.2020.109...
; Morison & Hartel, 2018Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9.
http://dx.doi.org/10.1201/9780429449734-...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
).

Effect of freeze concentration process in dairy products

Studies and equipment development about freeze concentration of dairy products have resulted in knowledge about the performance of dairy fluids at low temperatures, the impact on the milk physicochemical properties and the influence on the behavior of the main components such as lactose precipitation, protein conformation, and fat dispersion in both the concentrate and the ice fraction (Balde & Aider, 2016Balde, A., & Aider, M. (2016). Impact of cryoconcentration on casein micelle size distribution, micelles inter-distance, and flow behavior of skim milk during refrigerated storage. Innovative Food Science & Emerging Technologies, 34, 68-76. http://dx.doi.org/10.1016/j.ifset.2015.12.032.
http://dx.doi.org/10.1016/j.ifset.2015.1...
; Barros et al., 2022aBarros, E. L. S., Silva, C. C., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudencio, E. S. (2022a). Effect of replacement of milk by block freeze concentrated whey in physicochemical and rheological properties of ice cream. Food Science and Technology, 42, e12521. http://dx.doi.org/10.1590/fst.12521.
http://dx.doi.org/10.1590/fst.12521...
, 2022bBarros, E. L. S., Silva, C. C., Verruck, S., Canella, M. H. M., Maran, B. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). Concentrated whey from block freeze concentration or milk-based ice creams on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. Food Science and Technology, 42, e84021. http://dx.doi.org/10.1590/fst.84021.
http://dx.doi.org/10.1590/fst.84021...
; Muñoz et al., 2019Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263. PMid:30286622.
http://dx.doi.org/10.1177/10820132188032...
; Sánchez et al., 2011aSánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479. PMid:21364040.
http://dx.doi.org/10.1177/10820132103824...
).

During the concentration, there is an increase of soluble solids in the concentrated dairy fraction, with a tendency to increase the viscosity of the concentrate. The high concentration of caseins and their consequent dehydration causes an increase of micelles volume and in the inter-micelles interaction, which strongly contribute to the viscosity of milk. Any chemical or physical effect, as well as the concentration, that may change the aggregation state of casein micelle, certainly will modify the viscosity of milk. As a result, the increase of the viscosity is inversely proportional to the ability of separate the concentrate from the ice fraction, which limits the concentration efficiency (Balde & Aider, 2016Balde, A., & Aider, M. (2016). Impact of cryoconcentration on casein micelle size distribution, micelles inter-distance, and flow behavior of skim milk during refrigerated storage. Innovative Food Science & Emerging Technologies, 34, 68-76. http://dx.doi.org/10.1016/j.ifset.2015.12.032.
http://dx.doi.org/10.1016/j.ifset.2015.1...
; Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Bienvenue et al., 2003Bienvenue, A., Jiménez-Flores, R., & Singh, H. (2003). Rheological properties of concentrated skim milk: importance of soluble minerals in the changes in viscosity during storage. Journal of Dairy Science, 86(12), 3813-3821. http://dx.doi.org/10.3168/jds.S0022-0302(03)73988-5. PMid:14740815.
http://dx.doi.org/10.3168/jds.S0022-0302...
). In addition, high milk soluble solids content (proteins, fat, or lactose) may affect the crystallization and development of pure ice crystals, affecting the efficiency in the separation step and restricting the phenomenon of heat and mass transference.

Alternative studies employing previous treatments to remove fat from whole milk or directing skimmed milk to freeze concentration were carried out to reduce the effect of fat during the concentration and improve the efficiency of ice crystals separation (Aider & Ounis, 2012Aider, M., & Ounis, W. B. (2012). Skim milk cryoconcentration as affected by the thawing mode: gravitational vs. microwave-assisted. International Journal of Food Science & Technology, 47(1), 195-202. http://dx.doi.org/10.1111/j.1365-2621.2011.02826.x.
http://dx.doi.org/10.1111/j.1365-2621.20...
; Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
; Barros et al., 2022bBarros, E. L. S., Silva, C. C., Verruck, S., Canella, M. H. M., Maran, B. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). Concentrated whey from block freeze concentration or milk-based ice creams on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. Food Science and Technology, 42, e84021. http://dx.doi.org/10.1590/fst.84021.
http://dx.doi.org/10.1590/fst.84021...
; Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
; Muñoz et al., 2019Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263. PMid:30286622.
http://dx.doi.org/10.1177/10820132188032...
). Compared to skimmed milk, the fat content in the dairy matrix increases the resistance in removing the ice fraction of concentrated whole milk due to the interaction/adsorption of caseins with fat globules. This interaction is responsible for the formation of large particles and the presence of a clumped that interferes in the separation of ice crystals (Tribst et al., 2020Tribst, A. A. L., Falcade, L. T. P., Carvalho, N. S., Cristianini, M., Leite, B. R. C. Jr., & Oliveira, M. M. (2020). Using physical processes to improve physicochemical and structural characteristics of fresh and frozen/thawed sheep milk. Innovative Food Science & Emerging Technologies, 59, 102247. http://dx.doi.org/10.1016/j.ifset.2019.102247.
http://dx.doi.org/10.1016/j.ifset.2019.1...
). In addition, the milk fat fraction can also influence the lactose distribution in the concentration process, directing the high lactose content in the ice fraction, which contains most hydrophilic compounds (Aider & Halleux, 2009Aider, M., & Halleux, D. (2009). Cryoconcentration technology in the bio-food industry: principles and applications. Lebensmittel-Wissenschaft + Technologie, 42(3), 679-685. http://dx.doi.org/10.1016/j.lwt.2008.08.013.
http://dx.doi.org/10.1016/j.lwt.2008.08....
).

The milk color is one of the physical parameters that most influence sensory acceptance, mainly whiteness. In the freeze concentration process, the whiteness and luminosity can be improved according to the conformation of caseins in the concentrate. Comparing the physicochemical parameters of skimmed powdered milk from traditional concentration methods (evaporation) and alternative processes before drying, such as the freeze concentration, Balde & Aïder (2017)Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
obtained products with high luminosity, good flow, and heat stability of milk powders from a previous freeze concentration. The high whiteness and luminosity can be attributed to an aggregation of denatured whey proteins and casein micelles, forming large particles. Compared to the traditional evaporation, significant differences can be attributed to the high temperatures involved in this process, which causes the formation of melanoidins or Maillard Reaction Products (MRP), with a typical caramel-brown color (Perusko et al., 2021Perusko, M., Ghnimi, S., Simovic, A., Stevanovic, N., Radomirovic, M., Gharsallaoui, A., Smiljanic, K., Van Haute, S., Stanic-Vucinic, D., & Velickovic, T. C. (2021). Maillard reaction products formation and antioxidative power of spray dried camel milk powders increases with the inlet temperature of drying. LWT, 143, 111091. http://dx.doi.org/10.1016/j.lwt.2021.111091.
http://dx.doi.org/10.1016/j.lwt.2021.111...
).

Freeze concentration processes can be easily applied in dairy manufacturing with the purpose to produce stable concentrated products with high dry matter content without the need to enrich the formulation with whey proteins, powdered milk, or additives to improve the color of dairy products (Balde & Aïder, 2017Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016.
http://dx.doi.org/10.1016/j.powtec.2017....
). Studies report that freeze concentration is an important technology to promote high lightness, viscosity, and overrun for ice creams with skimmed milk freeze concentrated (Camelo-Silva et al., 2022aCamelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221.
http://dx.doi.org/10.1590/fst.12221...
) and replaced with whey concentrate (Barros et al., 2022aBarros, E. L. S., Silva, C. C., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudencio, E. S. (2022a). Effect of replacement of milk by block freeze concentrated whey in physicochemical and rheological properties of ice cream. Food Science and Technology, 42, e12521. http://dx.doi.org/10.1590/fst.12521.
http://dx.doi.org/10.1590/fst.12521...
) (Table 1). In addition, recent researches indicate that the high dry matter of the concentrate can offer a large concentration of nutrients and substrates for the development of probiotic cells and be a good carrier in dairy products, ensuring a high quality and functional value (Camelo-Silva et al., 2022bCamelo-Silva, C., Barros, E. L. S., Verruck, S., Maran, B. M., Canella, M. H. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). How ice cream manufactured with concentrated milk serves as a protective probiotic carrier? An in vitro gastrointestinal assay. Food Science and Technology, 42, e28621. http://dx.doi.org/10.1590/fst.28621.
http://dx.doi.org/10.1590/fst.28621...
; Canella et al., 2018Canella, M. H. M., Muñoz, I. B., Pinto, S. S., Liz, G. R., Müller, C. M. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). Use of concentrated whey by freeze concentration process to obtain a symbiotic fermented lactic beverage. Advance Journal of Food Science and Technology, 14(2), 56-68. http://dx.doi.org/10.19026/ajfst.14.5832.
http://dx.doi.org/10.19026/ajfst.14.5832...
; Liz et al., 2020Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752. PMid:31882096.
http://dx.doi.org/10.1016/j.foodres.2019...
; Muñoz et al., 2018Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009.
http://dx.doi.org/10.1016/j.lwt.2018.08....
).

3.2 Membrane separation process

Membrane separation is an emerging food processing technology that can provide milk preservation at low temperatures, increasing the shelf-life (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
). In dairy manufacturing, this popular separation process can be used to improve the microbial quality of dairy products and maintain the nutritional and functional properties of milk bioactive compounds (Henriques et al., 2020Henriques, M. H. F., Gomes, D. M. G. S., Borges, A. R., & Pereira, C. J. D. (2020). Liquid whey protein concentrates as primary raw material for acid dairy gels. Food Science and Technology, 40(2), 361-369. http://dx.doi.org/10.1590/fst.43218.
http://dx.doi.org/10.1590/fst.43218...
; Prudêncio et al., 2014Prudêncio, E. S., Müller, C. M. O., Fritzen-Freire, C. B., Amboni, R. D. M. C., & Petrus, J. C. C. (2014). Effect of whey nanofiltration process combined with diafiltration on the rheological and physicochemical properties of ricotta cheese. Food Research International, 56, 92-99. http://dx.doi.org/10.1016/j.foodres.2013.12.017.
http://dx.doi.org/10.1016/j.foodres.2013...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). Compared to traditional separation processes, the membrane technology is favored due to the operation at moderate temperatures, pressure, and high selectivity during the procedure, which do not change organoleptic characteristics of dairy products (Galvão, 2018Galvão, D. F. (2018). Membrane technology and water reuse in a dairy industry. In N. Koca (Ed.), Technological approaches for novel applications in dairy processing. London: IntechOpen. http://dx.doi.org/10.5772/intechopen.76464
http://dx.doi.org/10.5772/intechopen.764...
; Kim & Min, 2019Kim, S.-H., & Min, C.-S. (2019). Fouling reduction using the resonance vibration in membrane separation of whole milk. Journal of Industrial and Engineering Chemistry, 75, 123-129. http://dx.doi.org/10.1016/j.jiec.2019.03.011.
http://dx.doi.org/10.1016/j.jiec.2019.03...
; Velpula, 2017Velpula, S. (2017). Dairy wastewater treatment by membrane systems - a review. International Journal of Pure & Applied Bioscience, 5(6), 389-395. http://dx.doi.org/10.18782/2320-7051.5540.
http://dx.doi.org/10.18782/2320-7051.554...
). In addition, unlike conventional methods, membrane separation is a very attractive alternative technology due to the required temperature does not involve solvent phase change, which increases energy savings in this concentration process and represents an energy-efficient alternative to the concentration of dairy products (Table 1) (Bahnasawy & Shenana, 2010Bahnasawy, A. H., & Shenana, M. E. (2010). Flux behavior and energy consumption of ultrafiltration (UF) process of milk. Australian Journal of Agricultural Engineering, 1(2), 54-65.; Faucher et al., 2021Faucher, M., Perreault, V., Ciftci, O. N., Gaaloul, S., & Bazinet, L. (2021). Phospholipid recovery from sweet whey and whey protein concentrate: use of electrodialysis with bipolar membrane combined with a dilution factor as an ecoefficient method. Future Foods, 4, 100052. http://dx.doi.org/10.1016/j.fufo.2021.100052.
http://dx.doi.org/10.1016/j.fufo.2021.10...
; Marx & Kulozik, 2018Marx, M., & Kulozik, U. (2018). Thermal denaturation kinetics of whey proteins in reverse osmosis and nanofiltration sweet whey concentrates. International Dairy Journal, 85, 270-279. http://dx.doi.org/10.1016/j.idairyj.2018.04.009.
http://dx.doi.org/10.1016/j.idairyj.2018...
; Prudêncio et al., 2014Prudêncio, E. S., Müller, C. M. O., Fritzen-Freire, C. B., Amboni, R. D. M. C., & Petrus, J. C. C. (2014). Effect of whey nanofiltration process combined with diafiltration on the rheological and physicochemical properties of ricotta cheese. Food Research International, 56, 92-99. http://dx.doi.org/10.1016/j.foodres.2013.12.017.
http://dx.doi.org/10.1016/j.foodres.2013...
).

The principle of this process occurs similarly to a pressure filtration system with membranes (thin film) to separate two solutions acting as a selective barrier. The separation is based on the permeability of membrane pores, separating immiscible solids and soluble solids, and the systems of separation are developed according to the direction of feed flow, which can be tangential or perpendicular. When the liquid passes through the membrane in a single direction, pores clogging may occur. On the other hand, in the tangential system, there are two directions of current passing through the membrane: one that flows parallel to the membrane removing the trapped solids, and the other purified, that passes through it. In this system, the parallel flow assists in the removal of particles that could clog the membrane pores. After passing through the pores, the liquid matrix is separated into two fractions: the permeate or microfiltrated, which is the liquid that passes through the pores, and the retentate (Figure 4). This fraction contains a higher concentration of solids that have a bigger size than the pore diameter of the membrane (Bahnasawy & Shenana, 2010Bahnasawy, A. H., & Shenana, M. E. (2010). Flux behavior and energy consumption of ultrafiltration (UF) process of milk. Australian Journal of Agricultural Engineering, 1(2), 54-65.; Valencia et al., 2018Valencia, A. P., Doyen, A., Benoit, S., Margni, M., & Pouliot, Y. (2018). Effect of ultrafiltration of milk prior to fermentation on mass balance and process efficiency in Greek-style yogurt manufacture. Foods, 7(9), 144. http://dx.doi.org/10.3390/foods7090144. PMid:30181438.
http://dx.doi.org/10.3390/foods7090144...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
).

Figure 4
A schematic overview of the membrane separation method.

The selectivity in separation depends on the process conditions and the type of membrane, relating the pore size and molecular-weight cutoff. The separation procedure can be classified as Microfiltration (MF), Ultrafiltration (UF), Nanofiltration (NF), and Reverse Osmosis (RO) (Figure 5) (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
). In dairy manufacturing, beyond to being used for the separation of solid milk components, MF is widely applied in reducing microbiological counts, with the biggest pore size (0.1-10 μm) and the lowest process pressure (0.01-0.2 MPa). According to specific pore size, micellar caseins (50-500 nm), whey proteins (3-6 nm), lactose (1 nm), minerals and water can permeate the membrane, while fat globules (10 μm) are separated, and bacteria (10-100 μm), spores (1 μm), and somatic cells are removed (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Schäfer et al., 2018Schäfer, J., Bast, R., Atamer, Z., Nöbel, S., Kohlus, R., & Hinrichs, J. (2018). Concentration of skim milk by means of dynamic filtration using overlapping rotating ceramic membrane disks. International Dairy Journal, 78, 11-19. http://dx.doi.org/10.1016/j.idairyj.2017.10.004.
http://dx.doi.org/10.1016/j.idairyj.2017...
; Smith, 2013Smith, K. (2013). Development of membrane processes. In A. Y. Tamime (Ed.), Membrane processing: dairy and beverage application (pp. 1-9). Chichester: Wiley-Blackwell.; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). In this case, microfiltration is important in ensuring safe food for consumption, removing spores that are not inactivated in the milk pasteurization/sterilization process, in addition to extending shelf life, since somatic cells induce lipolytic and proteolytic milk reactions, damaging the sensory characteristics, color, flavor, and texture (Ma et al., 2000Ma, Y., Ryan, C., Barbano, D. M., Galton, D. M., Rudan, M. A., & Boor, K. J. (2000). Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk. Journal of Dairy Science, 83(2), 264-274. http://dx.doi.org/10.3168/jds.S0022-0302(00)74873-9. PMid:10714859.
http://dx.doi.org/10.3168/jds.S0022-0302...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
).

Figure 5
Passed and rejected dairy components based on membrane pore size. Adapted from Carter et al. (2021)Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
. Note: MF = microfiltration, UF = ultrafiltration, NF = nanofiltration, RO = reverse osmosis.

For UF processes, the pore size ranges from 10 to 100 nm, operating at pressures of 0.1 to 1.0 MPa and, in milk concentration, proteins and fat fraction are retained providing a retentate rich in the dry matter that can be used in the production of high added value concentrated products. The permeate is composed of water, minerals, and lactose, which can be isolated and purified (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Smith, 2013Smith, K. (2013). Development of membrane processes. In A. Y. Tamime (Ed.), Membrane processing: dairy and beverage application (pp. 1-9). Chichester: Wiley-Blackwell.; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). The NF (1-10 nm of pore size and pressure of 1.5-3.0 MPa) is a fractionation technique with a concentration of substances having a molar mass between 100 and 1000 Da (g mol-1) and are applied for whey processing in order to increase protein content (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Marx & Kulozik, 2018Marx, M., & Kulozik, U. (2018). Thermal denaturation kinetics of whey proteins in reverse osmosis and nanofiltration sweet whey concentrates. International Dairy Journal, 85, 270-279. http://dx.doi.org/10.1016/j.idairyj.2018.04.009.
http://dx.doi.org/10.1016/j.idairyj.2018...
; Merkel et al., 2021Merkel, A., Voropaeva, D., & Ondrušek, M. (2021). The impact of integrated nanofiltration and electrodialytic processes on the chemical composition of sweet and acid whey streams. Journal of Food Engineering, 298, 110500. http://dx.doi.org/10.1016/j.jfoodeng.2021.110500.
http://dx.doi.org/10.1016/j.jfoodeng.202...
; Prudêncio et al., 2014Prudêncio, E. S., Müller, C. M. O., Fritzen-Freire, C. B., Amboni, R. D. M. C., & Petrus, J. C. C. (2014). Effect of whey nanofiltration process combined with diafiltration on the rheological and physicochemical properties of ricotta cheese. Food Research International, 56, 92-99. http://dx.doi.org/10.1016/j.foodres.2013.12.017.
http://dx.doi.org/10.1016/j.foodres.2013...
; Smith, 2013Smith, K. (2013). Development of membrane processes. In A. Y. Tamime (Ed.), Membrane processing: dairy and beverage application (pp. 1-9). Chichester: Wiley-Blackwell.). RO is a concentration technique, with the smaller pore size (< 1 nm) and the higher processing pressure (3.0-5.0 MPa), which are related to increasing the stability and the shelf life of whey concentrates (Marx et al., 2018Marx, M., Bernauer, S., & Kulozik, U. (2018). Manufacturing of reverse osmosis whey concentrates with extended shelf life and high protein nativity. International Dairy Journal, 86, 57-64. http://dx.doi.org/10.1016/j.idairyj.2018.06.019.
http://dx.doi.org/10.1016/j.idairyj.2018...
; Marx & Kulozik, 2018Marx, M., & Kulozik, U. (2018). Thermal denaturation kinetics of whey proteins in reverse osmosis and nanofiltration sweet whey concentrates. International Dairy Journal, 85, 270-279. http://dx.doi.org/10.1016/j.idairyj.2018.04.009.
http://dx.doi.org/10.1016/j.idairyj.2018...
).

Effect of membrane separation processes in dairy products

Membrane separation systems at high-pressure processing have become an interesting alternative to concentrate dairy products, since this technology, in addition to acting on the removal of pathogens and spores, can reduce the loss of nutritional compounds, maintain the maximum of milk properties, enable high flow rates and improve the yield (Stratakos et al., 2019Stratakos, A. C., Inguglia, E. S., Linton, M., Tollerton, J., Murphy, L., Corcionivoschi, N., Koidis, A., & Tiwari, B. K. (2019). Effect of high pressure processing on the safety, shelf life and quality of raw milk. Innovative Food Science & Emerging Technologies, 52, 325-333. http://dx.doi.org/10.1016/j.ifset.2019.01.009.
http://dx.doi.org/10.1016/j.ifset.2019.0...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
).

The separation of the milk protein fraction (caseins and whey proteins) is gaining considerable attention from dairy and beverage manufacturers due to its unique protein profile and functionality. Membrane separation technologies, in special the MF and UF, are promising in cheesemaking, which provide a micro/ultrafiltered milk that can be used for protein standardization and improve the texture and yield of cheeses (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Faion et al., 2019Faion, A. M., Becker, J., Fernandes, I. A., Steffens, J., & Valduga, E. (2019). Sheep’s milk concentration by ultrafiltration and cheese elaboration. Journal of Food Process Engineering, 42(4). http://dx.doi.org/10.1111/jfpe.13058.
http://dx.doi.org/10.1111/jfpe.13058...
). In a Peccorino cheese production from ultrafiltered sheep's milk by Faion et al. (2019)Faion, A. M., Becker, J., Fernandes, I. A., Steffens, J., & Valduga, E. (2019). Sheep’s milk concentration by ultrafiltration and cheese elaboration. Journal of Food Process Engineering, 42(4). http://dx.doi.org/10.1111/jfpe.13058.
http://dx.doi.org/10.1111/jfpe.13058...
, the ultrafiltered milk provided a nearly fourfold increase in protein (37%) and fat (29%) content, increasing the cheese yield by 17%. In addition, the time and moderate temperature of the ultrafiltration process (22 °C for 30 min) can favor the development of lactic acid bacteria for fermented dairy products (Table 2).

Table 2
Recent studies on alternative technologies applied to dairy concentration.

In the permeate, minerals and lactose fraction can be affected due to protein interactions and deposition on the membrane surface. According to the specific pore size, these interactions result in a gel layer formation, clogging the pores and exerting resistance to the passage of water, minerals, and lactose, which contains low molecular mass. For minerals, only two-thirds that are bound with micellar proteins (usually calcium phosphate) remain retained in the membrane, while the soluble ones are permeated through it (Faion et al., 2019Faion, A. M., Becker, J., Fernandes, I. A., Steffens, J., & Valduga, E. (2019). Sheep’s milk concentration by ultrafiltration and cheese elaboration. Journal of Food Process Engineering, 42(4). http://dx.doi.org/10.1111/jfpe.13058.
http://dx.doi.org/10.1111/jfpe.13058...
). Minerals that pass with the whey fraction by interactions or in the form of free ions and salts, may impact the functional properties of the permeate, in its buffering capacity and influence the cheesemaking (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Marx et al., 2018Marx, M., Bernauer, S., & Kulozik, U. (2018). Manufacturing of reverse osmosis whey concentrates with extended shelf life and high protein nativity. International Dairy Journal, 86, 57-64. http://dx.doi.org/10.1016/j.idairyj.2018.06.019.
http://dx.doi.org/10.1016/j.idairyj.2018...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). In addition, the temperature in membrane separation can influence the distribution of constituents and physicochemical properties of milk. According to France et al. (2021)France, T. C., Bot, F., Kelly, A. L., Crowley, S. V., & O’Mahony, J. A. (2021). The influence of temperature on filtration performance and fouling during cold microfiltration of skim milk. Separation and Purification Technology, 262, 118256. http://dx.doi.org/10.1016/j.seppur.2020.118256.
http://dx.doi.org/10.1016/j.seppur.2020....
, MF of skimmed milk was performed at 4, 8, and 12 °C. During the separation, the mechanical and thermal energy requirements during the MF of skimmed milk were strongly dependent on processing temperature (at 4 °C = 27.6 KWh, at 8 °C = 24.6 KWh and 12 °C = 22.9 × 10-3 KWh) with the highest energy requirements for UF at 4 °C due to the high viscosity and the generation of heat during pumping, increasing the energy required to maintain the lower temperature. For protein contents, the fouling of the membrane caused by casein micelles decreased the concentration of β-casein, β-lactoglobulin and α-lactalbumin in the permeate throughout MF. However, the dissociation of β-casein into the whey fraction is higher at lower temperatures allowing for increased partitioning thereof into the permeate at 4 °C (Coppola et al., 2014Coppola, L. E., Molitor, M. S., Rankin, S. A., & Lucey, J. A. (2014). Comparison of milk-derived whey protein concentrates containing various levels of casein. International Journal of Dairy Technology, 67(4), 467-473. http://dx.doi.org/10.1111/1471-0307.12157.
http://dx.doi.org/10.1111/1471-0307.1215...
). The MF at lower temperatures may enable the production of next-generation dairy streams with novel protein fractions (France et al., 2021France, T. C., Bot, F., Kelly, A. L., Crowley, S. V., & O’Mahony, J. A. (2021). The influence of temperature on filtration performance and fouling during cold microfiltration of skim milk. Separation and Purification Technology, 262, 118256. http://dx.doi.org/10.1016/j.seppur.2020.118256.
http://dx.doi.org/10.1016/j.seppur.2020....
).

During the flow of milk through the membranes, the applied pressure minimally affects the protein content and fat globules when compared to a concentration in processes with high temperatures and mechanical impacts (Jukkola et al., 2018Jukkola, A., Partanen, R., Rojas, O. J., & Heino, A. (2018). Effect of heat treatment and pH on the efficiency of micro-diafiltration for the separation of native fat globules from cream in butter production. Journal of Membrane Science, 548, 99-107. http://dx.doi.org/10.1016/j.memsci.2017.11.012.
http://dx.doi.org/10.1016/j.memsci.2017....
). The process must be monitored to maintain a suitable functioning of the membranes due to possible cake formation on the surface or pore blocking caused by casein micelle sizes (Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). According to studies, whey proteins of pasteurized skimmed milk (> 78 °C) can denature and form aggregates with minerals or can adhere to casein micelles, clogging the membrane pores (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
; Saboyainsta & Maubois, 2000Saboyainsta, L. V., & Maubois, J.-L. (2000). Current developments of microfiltration technology in the dairy industry. Le Lait, 80(6), 541-553. http://dx.doi.org/10.1051/lait:2000144.
http://dx.doi.org/10.1051/lait:2000144...
; Verruck et al., 2019bVerruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157.
http://dx.doi.org/10.17140/AFTNSOJ-5-157...
). This problem can affect the flux and modify the composition properties of the permeate and the retentate, which will not contain casein micelles but a product similar to milk protein concentrate due to the ratio of casein to whey protein (Carter et al., 2021Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811. PMid:33455742.
http://dx.doi.org/10.3168/jds.2020-18811...
). Recently, researches were developed to reduce the membrane fouling caused by casein micelles during the milk ultrafiltration (Mikhaylin et al., 2016Mikhaylin, S., Nikonenko, V., Pourcelly, G., & Bazinet, L. (2016). Hybrid bipolar membrane electrodialysis/ultrafiltration technology assisted by a pulsed electric field for casein production. Green Chemistry, 18(1), 307-314. http://dx.doi.org/10.1039/C5GC00970G.
http://dx.doi.org/10.1039/C5GC00970G...
, 2018Mikhaylin, S., Patouillard, L., Margni, M., & Bazinet, L. (2018). Milk protein production by a more environmentally sustainable process: bipolar membrane electrodialysis coupled with ultrafiltration. Green Chemistry, 20(2), 449-456. http://dx.doi.org/10.1039/C7GC02154B.
http://dx.doi.org/10.1039/C7GC02154B...
). A bipolar membrane electrodialysis was coupled with ultrafiltration, allowing the production of H+ and OH- ions from water under the application of an electric current. The milk is acidified in the electrodialysis module and caseins are precipitated and separated from whey proteins, without clogging. In addition, the base generated by the bipolar membrane can be applied in the conversion of insoluble caseins micelles into their soluble form of caseinates, without the use of chemicals and is considered a more environmentally sustainable process (Mikhaylin et al., 2018Mikhaylin, S., Patouillard, L., Margni, M., & Bazinet, L. (2018). Milk protein production by a more environmentally sustainable process: bipolar membrane electrodialysis coupled with ultrafiltration. Green Chemistry, 20(2), 449-456. http://dx.doi.org/10.1039/C7GC02154B.
http://dx.doi.org/10.1039/C7GC02154B...
). Sustainable strategies are also developed for application in ultrafiltration and nanofiltration of whey, with an obtention of nonacidified whey permeate before further application and reducing this major by-product generated by dairy industries (Faucher et al., 2021Faucher, M., Perreault, V., Ciftci, O. N., Gaaloul, S., & Bazinet, L. (2021). Phospholipid recovery from sweet whey and whey protein concentrate: use of electrodialysis with bipolar membrane combined with a dilution factor as an ecoefficient method. Future Foods, 4, 100052. http://dx.doi.org/10.1016/j.fufo.2021.100052.
http://dx.doi.org/10.1016/j.fufo.2021.10...
; Merkel et al., 2021Merkel, A., Voropaeva, D., & Ondrušek, M. (2021). The impact of integrated nanofiltration and electrodialytic processes on the chemical composition of sweet and acid whey streams. Journal of Food Engineering, 298, 110500. http://dx.doi.org/10.1016/j.jfoodeng.2021.110500.
http://dx.doi.org/10.1016/j.jfoodeng.202...
). Although membrane fouling is something recurrent, these study alternatives can improve the efficiency of the membrane separation process, which is currently one of the emerging technologies with great potential to replace traditional dairy concentration methods in large-scale.

3.3 Freeze-drying

The freeze-drying technology, or lyophilization, is a concentration process based on the phenomenon of water sublimation of the food composition. At low temperatures, the water fraction is separated from the food by crystallization below its triple point (0.01 °C) and then is directly transformed from the solid-state to the vapor phase at high pressures (approximately 611 Pa) (Bando et al., 2017Bando, K., Kansha, Y., Ishizuka, M., & Tsutsumi, A. (2017). Innovative freeze-drying process based on self-heat recuperation technology. Journal of Cleaner Production, 168, 1244-1250. http://dx.doi.org/10.1016/j.jclepro.2017.09.088.
http://dx.doi.org/10.1016/j.jclepro.2017...
; Waghmare et al., 2021Waghmare, R. B., Perumal, A. B., Moses, J. A., & Anandharamakrishnan, C. (2021). Recent developments in freeze drying of foods. In K. Knoerzer & K. Muthukumarappan (Eds.), Innovative food processing technologies: a comprehensive review (pp. 82-99). Amsterdam: Elsevier. http://dx.doi.org/10.1016/B978-0-12-815781-7.00017-2
http://dx.doi.org/10.1016/B978-0-12-8157...
). The concentration at freezing temperatures limits the damage of thermolabile compounds and is an advantageous technology to retain more taste, aroma, and color when compared to other concentration methods, being also an interesting alternative to concentrate dairy products, providing an increase of their quality (Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Vincenzetti et al., 2018Vincenzetti, S., Cecchi, T., Perinelli, D. R., Pucciarelli, S., Polzonetti, V., Bonacucina, G., Ariani, A., Parrocchia, L., Spera, D. M., Ferretti, E., Vallesi, P., & Polidori, P. (2018). Effects of freeze-drying and spray-drying on donkey milk volatile compounds and whey proteins stability. LWT, 88, 189-195. http://dx.doi.org/10.1016/j.lwt.2017.10.019.
http://dx.doi.org/10.1016/j.lwt.2017.10....
; Zhu et al., 2020Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Impact of freeze-drying and subsequent storage on milk metabolites based on 1H NMR and UHPLC-QToF/MS. Food Control, 116, 107017. http://dx.doi.org/10.1016/j.foodcont.2019.107017.
http://dx.doi.org/10.1016/j.foodcont.201...
).

The market of freeze-dried products is increasing; however, it is necessary to reduce the high energy consumption of the process, ranging from 3820 to 5500 kJ.kg-1: the highest energy requirement among all the concentration processes (Table 1) (Bando et al., 2017Bando, K., Kansha, Y., Ishizuka, M., & Tsutsumi, A. (2017). Innovative freeze-drying process based on self-heat recuperation technology. Journal of Cleaner Production, 168, 1244-1250. http://dx.doi.org/10.1016/j.jclepro.2017.09.088.
http://dx.doi.org/10.1016/j.jclepro.2017...
; Keselj et al., 2017Keselj, K., Pavkov, I., Radojcin, M., & Stamenkovic, Z. (2017). Comparison of energy consumption in the convective and freeze drying of raspberries. Journal on Processing and Energy in Agriculture, 21(4), 192-196. http://dx.doi.org/10.5937/JPEA1704192K.
http://dx.doi.org/10.5937/JPEA1704192K...
). Compared to conventional drying, which dehydrates foods in a single stage, the freeze-drying time is longer and consumes large amounts of energy (almost double to remove 1 kg of water) (Duan et al., 2016Duan, X., Yang, X., Ren, G., Pang, Y., Liu, L., & Liu, Y. (2016). Technical aspects in freeze-drying of foods. Drying Technology, 34(11), 1271-1285. http://dx.doi.org/10.1080/07373937.2015.1099545.
http://dx.doi.org/10.1080/07373937.2015....
). In addition, energy is required to freeze the food, maintain the high pressure, sublimate water crystals and condense water vapor. This concentration process becomes expansive and is usually applied in high value-added products and makes the processing of common and accessible concentrated products unfeasible (Garcia-Amezquita et al., 2016Garcia-Amezquita, L. E., Welti-Chanes, J., Vergara-Balderas, F. T., & Bermúdez-Aguirre, D. (2016). Freeze-drying: the basic process. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 104-109). Oxford: Elsevier. http://dx.doi.org/10.1016/B978-0-12-384947-2.00328-7
http://dx.doi.org/10.1016/B978-0-12-3849...
; Waghmare et al., 2021Waghmare, R. B., Perumal, A. B., Moses, J. A., & Anandharamakrishnan, C. (2021). Recent developments in freeze drying of foods. In K. Knoerzer & K. Muthukumarappan (Eds.), Innovative food processing technologies: a comprehensive review (pp. 82-99). Amsterdam: Elsevier. http://dx.doi.org/10.1016/B978-0-12-815781-7.00017-2
http://dx.doi.org/10.1016/B978-0-12-8157...
).

The design of a freeze-dryer is composed of four basic components: drying chamber, vacuum pump, heat source, and condenser (Figure 6). For milk processing, it becomes usual to apply a vacuum freeze dryer. In this method, freezing can be done directly in the freeze-dryer or other equipment that makes this step possible. The vacuum system is a combination of a water circulation pump and oil-sealed pump. During the initial stage of the vacuum process, the air is removed by the high-power oil sealed pump causing a decrease in pressure. After this procedure, the vacuum is maintained by a low-power pump. For the frozen water fraction to change state, passing from the solid-state directly to steam, a heating system is needed to raise the temperature and prevent the change from the solid to the liquid phase. In this system, it can contain plates with steam circulation or hot water at 120 °C. Cooling for steam condensation is equipped by a system with liquid refrigerant circulating on plates behind or on the sides of the freeze dryer (Duan et al., 2016Duan, X., Yang, X., Ren, G., Pang, Y., Liu, L., & Liu, Y. (2016). Technical aspects in freeze-drying of foods. Drying Technology, 34(11), 1271-1285. http://dx.doi.org/10.1080/07373937.2015.1099545.
http://dx.doi.org/10.1080/07373937.2015....
; Garcia-Amezquita et al., 2016Garcia-Amezquita, L. E., Welti-Chanes, J., Vergara-Balderas, F. T., & Bermúdez-Aguirre, D. (2016). Freeze-drying: the basic process. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 104-109). Oxford: Elsevier. http://dx.doi.org/10.1016/B978-0-12-384947-2.00328-7
http://dx.doi.org/10.1016/B978-0-12-3849...
; Waghmare et al., 2021Waghmare, R. B., Perumal, A. B., Moses, J. A., & Anandharamakrishnan, C. (2021). Recent developments in freeze drying of foods. In K. Knoerzer & K. Muthukumarappan (Eds.), Innovative food processing technologies: a comprehensive review (pp. 82-99). Amsterdam: Elsevier. http://dx.doi.org/10.1016/B978-0-12-815781-7.00017-2
http://dx.doi.org/10.1016/B978-0-12-8157...
).

Figure 6
A typical freeze-dryer system. Adapted from Garcia-Amezquita et al. (2016)Garcia-Amezquita, L. E., Welti-Chanes, J., Vergara-Balderas, F. T., & Bermúdez-Aguirre, D. (2016). Freeze-drying: the basic process. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 104-109). Oxford: Elsevier. http://dx.doi.org/10.1016/B978-0-12-384947-2.00328-7
http://dx.doi.org/10.1016/B978-0-12-3849...
.

Effects of freeze-drying process in the dairy products composition

Due to the constant consumer demand for foods with higher functional and nutritional quality, the food formulation has been adapted with the replacement of natural components by freeze-dried products. As well as other emerging technologies, freeze-drying in addition to concentrating food can also be considered a method of preserving food products (Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Vincenzetti et al., 2018Vincenzetti, S., Cecchi, T., Perinelli, D. R., Pucciarelli, S., Polzonetti, V., Bonacucina, G., Ariani, A., Parrocchia, L., Spera, D. M., Ferretti, E., Vallesi, P., & Polidori, P. (2018). Effects of freeze-drying and spray-drying on donkey milk volatile compounds and whey proteins stability. LWT, 88, 189-195. http://dx.doi.org/10.1016/j.lwt.2017.10.019.
http://dx.doi.org/10.1016/j.lwt.2017.10....
). Due to the low water activity, microbial development and enzymatic oxidations are delayed, allowing the concentrated product to be stored for a long time at room temperature. Furthermore, especially in dairy manufacturing, the use of low temperatures during the concentration step enables to maintain the color and flavor of the product (Deshwal et al., 2020Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
; Duan et al., 2016Duan, X., Yang, X., Ren, G., Pang, Y., Liu, L., & Liu, Y. (2016). Technical aspects in freeze-drying of foods. Drying Technology, 34(11), 1271-1285. http://dx.doi.org/10.1080/07373937.2015.1099545.
http://dx.doi.org/10.1080/07373937.2015....
; Silva et al., 2021Silva, S. H., Neves, I. C. O., Meira, A. C. F. O., Alexandre, A. C. S., Oliveira, N. L., & Resende, J. V. (2021). Freeze-dried petit suisse cheese produced with ora-pro-nóbis (Pereskia aculeata Miller) biopolymer and carrageenan mix. LWT, 149, 111764. http://dx.doi.org/10.1016/j.lwt.2021.111764.
http://dx.doi.org/10.1016/j.lwt.2021.111...
; Vincenzetti et al., 2018Vincenzetti, S., Cecchi, T., Perinelli, D. R., Pucciarelli, S., Polzonetti, V., Bonacucina, G., Ariani, A., Parrocchia, L., Spera, D. M., Ferretti, E., Vallesi, P., & Polidori, P. (2018). Effects of freeze-drying and spray-drying on donkey milk volatile compounds and whey proteins stability. LWT, 88, 189-195. http://dx.doi.org/10.1016/j.lwt.2017.10.019.
http://dx.doi.org/10.1016/j.lwt.2017.10....
; Waghmare et al., 2021Waghmare, R. B., Perumal, A. B., Moses, J. A., & Anandharamakrishnan, C. (2021). Recent developments in freeze drying of foods. In K. Knoerzer & K. Muthukumarappan (Eds.), Innovative food processing technologies: a comprehensive review (pp. 82-99). Amsterdam: Elsevier. http://dx.doi.org/10.1016/B978-0-12-815781-7.00017-2
http://dx.doi.org/10.1016/B978-0-12-8157...
).

The first investigation about the effect of freeze-drying on raw milk metabolites was proposed by Zhu et al. (2020)Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Impact of freeze-drying and subsequent storage on milk metabolites based on 1H NMR and UHPLC-QToF/MS. Food Control, 116, 107017. http://dx.doi.org/10.1016/j.foodcont.2019.107017.
http://dx.doi.org/10.1016/j.foodcont.201...
. About the contents of some organic acids, amino acids, and dipeptides, slight changes were detected, however, the authors pointed that these alterations may happen as a result of the incomplete re-dissolution process of the freeze-dried milk powder rather than the freeze-drying process. The concentration of orotic acid, a fatty acid naturally occurring in raw milk, was stable after the freeze-drying treatment. To the low storage temperatures (4 °C and -20 °C), metabolites barely changed when stored in a freezer over a long period, relating the freeze-drying as an effective concentration and preservation method for milk concentration with minimal changes on the metabolites.

Effects in milk composition were also proposed by Deshwal et al. (2020)Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117.
http://dx.doi.org/10.1016/j.lwt.2020.110...
, who compared camel milk powder produced by freeze-drying with the traditional method of spray drying (Table 2). According to this study, freeze-dried camel milk powder had the highest dispersibility (67.15%) and solubility (88.77%). This can be attributed to this process, which makes the products lighter than other drying methods. Low solid feed during freeze-drying results in porous particles as a large amount of water is removed during the stages of drying. The lowest acidity was obtained in freeze-dried camel milk powders when compared to the spray drying method (0.193% vs 0.211%), which can cause an increase of minerals precipitation, lactose degradation, and Maillard reactions with a considerable and irreversible pH decrease. These reactions, due to the application of high temperatures, also decreased the calcium and iron contents of camel milk powders when compared to a freeze-drying process (0.011-0.012 g/kg vs 13.71 and 15.33 g/kg, respectively), highlighting the important maintenance of nutritional and functional compounds in a concentration by freeze-drying. The structure of milk fat globules can also change according to specific concentration methods. In a study about the effects of freeze-drying and spray drying on the microstructure of milk fat globules, Yao et al. (2016)Yao, Y., Zhao, G., Yan, Y., Chen, C., Sun, C., Zou, X., Jin, Q., & Wang, X. (2016). Effects of freeze drying and spray drying on the microstructure and composition of milk fat globules. RSC Advances, 6(4), 2520-2529. http://dx.doi.org/10.1039/C5RA22323G.
http://dx.doi.org/10.1039/C5RA22323G...
pointed that the surfaces of some fat globules after freeze-drying became thicker than those from raw milk and after spray-drying. This technology can cause the formation of irregular flaky translucent sheets with sharp edges, whereas spray-dried fat globules are spherical particles (Zhu & Damodaran, 2011Zhu, D., & Damodaran, S. (2011). Composition, thermotropic properties, and oxidative stability of freeze-dried and spray-dried milk fat globule membrane isolated from cheese whey. Journal of Agricultural and Food Chemistry, 59(16), 8931-8938. http://dx.doi.org/10.1021/jf201688w. PMid:21766876.
http://dx.doi.org/10.1021/jf201688w...
). This phenomenon can be explained due to the amphiphilic phospholipids that tend to accumulate on the surface during freezing and then, the fat globules stick together during the freeze-drying process. In addition, the freeze-drying method caused an increase in fat globules, explained by the authors due to the formation of ice crystals and possible repulsion of foreign material away from the interstitials, causing globule aggregation. In addition, the osmotic pressure of the globules may have caused recombination in larger globules (Yao et al., 2016Yao, Y., Zhao, G., Yan, Y., Chen, C., Sun, C., Zou, X., Jin, Q., & Wang, X. (2016). Effects of freeze drying and spray drying on the microstructure and composition of milk fat globules. RSC Advances, 6(4), 2520-2529. http://dx.doi.org/10.1039/C5RA22323G.
http://dx.doi.org/10.1039/C5RA22323G...
).

The concentration by freeze-drying also can influence the physicochemical properties of a dairy product. In a development of a freeze-dried Petit Suisse cheese, Silva et al. (2021)Silva, S. H., Neves, I. C. O., Meira, A. C. F. O., Alexandre, A. C. S., Oliveira, N. L., & Resende, J. V. (2021). Freeze-dried petit suisse cheese produced with ora-pro-nóbis (Pereskia aculeata Miller) biopolymer and carrageenan mix. LWT, 149, 111764. http://dx.doi.org/10.1016/j.lwt.2021.111764.
http://dx.doi.org/10.1016/j.lwt.2021.111...
pointed that this concentration method can influence the conformation of protein networks of the product composition (Table 2). Microscopy of the freeze-dried samples showed structures with large porosities and low agglomeration, indicating minimal interaction between the particles. This characteristic is attributed to the sublimation process of the larger ice crystals that filled the formed cavities with available water in the protein matrix. The formation of large pores in a protein network may be caused by an increase in the positive electrical charge of casein micelles at pH < 4.6, reducing intercellular interactions and resulting in the formation of an opening (porous). The protein dehydration promoted by freezing can change the textural and rheological properties, attributing different viscosities after rehydrating. In addition to changes in the composition and dairy structure, freeze-drying has become an interesting and useful method to extend the shelf life of probiotic bacteria in dairy products. Due to damage to cell membranes by the formation of ice crystals and decreasing cell viability, microencapsulation is an alternative for the incorporation of probiotics into the medium, which was proposed by Jouki et al. (2021)Jouki, M., Khazaei, N., Rezaei, F., & Taghavian-Saeid, R. (2021). Production of synbiotic freeze-dried yoghurt powder using microencapsulation and cryopreservation of L. plantarum in alginate-skim milk microcapsules. International Dairy Journal, 122, 105133. http://dx.doi.org/10.1016/j.idairyj.2021.105133.
http://dx.doi.org/10.1016/j.idairyj.2021...
in development of a symbiotic freeze-dried yogurt powder using microencapsulation of L. plantarum (Table 2). After freeze-drying, the survival rate of probiotic cells ranged from 67.1-91.2%, with minimal effect of this process on microencapsulated cells (9.8-10.6% loss). L. plantarum microcapsules enriched tolerated the freeze-drying process, featuring the yoghurt powder as a probiotic product for 10 weeks at 25 °C.

Therefore, the use of freeze-drying technology, as well as all alternative concentration technologies, allows the development of functional dairy products, with their nutritional properties maintained and quality enriched, pointing out these unconventional methods as potential substitutes in the concentration of dairy products in the dairy sector.

4 Future perspectives in the replacement of traditional technologies by emerging processes in the concentration of dairy products

The concentration of dairy products becomes one of the main challenges for the food industry, due to the guarantee of products of high quality and linked to a low-cost process. Recent studies, even if carried out on a small scale, show an industrial potential in replacing traditional concentration technologies by emerging non-thermal alternatives.

New research and equipment refinement must be conducted with adaptations of promising laboratory results for large-volume production, as well as the development of specific equipment at low costs, in addition to increasing speed, yield, and soluble solids content in the concentration/separation steps, which can also be developed into a single operation in the same equipment’s section. These improvements would be fundamental mainly for freeze-drying and block freeze concentration technologies that carry out an efficient concentration process, but with low yields and, therefore, are not viable in industrial production today. The application of non-thermal concentration processes, in addition to ensuring a high nutritional and sensory quality to the dairy product, can be linked to processes with an environmental appeal, with the reduction of the use of non-renewable energy resources such as the block freeze concentration, and alternatives for the treatment of by-products from milk manufacturing in recent aspects of membrane separation processes.

With constant research and development in the dairy sector, the industrial replacement of traditional concentration technologies by non-thermal methods becomes a future potential and a differential in the final quality of the product, winning consumer preference and becoming an interesting alternative in the competitive industrial sector from an economic and technological perspective.

5 Conclusion

Concentrated dairy products are one of the most important manufactured goods for the dairy industry due to the high added value, reduced volume, and lower transport costs. In addition, concentration processes increase the shelf-life, which can expand distribution logistics. Evaporation and spray drying processes are thermal concentration methods that are still traditional in the dairy industry, however, they are unfeasible processes due to the requirement of high energy expenditure and the decrease of nutritional, functional, and sensory properties of milk and dairy products. Nowadays, studies about the application of emerging non-thermal concentration technologies have been explored as means to decrease the adverse effects of traditional processing and present promising alternatives for dairy industries. Among the emerging dairy concentration methods reported in this review, membrane separation processes are advantageous due to enabling high flow rates, capable of removing bacteria and spores from the matrix, low energy expenditure, and reduced total costs. On the other hand, freeze concentration and freeze-drying, however advantageous in keeping bioactive compounds in milk and enable an increase in the quality of concentrated products, become energy-expensive, have a low yield, and are unfeasible for large-scale production. Recent studies involving the application of unconventional processes in the concentration of dairy products are fundamental for the industrial sector, which makes it possible to implement emerging processes on a large scale and increase the quality of commercialized concentrated products.

Acknowledgements

The authors are grateful to National Council for Scientific and Technological Development (CNPq, Brazil) for the financial support [CNPq, 405965/2016-8], and to the Coordination of Improvement of Higher Education Personnel (CAPES, Brazil) by the scholarship [001].

  • Practical Application: Improving the quality of concentrated dairy products by non-thermal emerging technologies.
  • Funding

    This work was supported by the National Council for Scientific and Technological Development (CNPq, Brazil) [CNPq, 405965/2016-8]; the Coordination of Improvement of Higher Education Personnel (CAPES, Brazil) [001].

References

  • Aider, M., & Halleux, D. (2009). Cryoconcentration technology in the bio-food industry: principles and applications. Lebensmittel-Wissenschaft + Technologie, 42(3), 679-685. http://dx.doi.org/10.1016/j.lwt.2008.08.013
    » http://dx.doi.org/10.1016/j.lwt.2008.08.013
  • Aider, M., & Ounis, W. B. (2012). Skim milk cryoconcentration as affected by the thawing mode: gravitational vs. microwave-assisted. International Journal of Food Science & Technology, 47(1), 195-202. http://dx.doi.org/10.1111/j.1365-2621.2011.02826.x
    » http://dx.doi.org/10.1111/j.1365-2621.2011.02826.x
  • Al‐Hilphy, A. R., Ali, H. I., Al‐IEssa, S. A., Lorenzo, J. M., Barba, F. J., & Gavahian, M. (2020). Optimization of process variables on physicochemical properties of milk during an innovative refractance window concentration. Journal of Food Processing and Preservation, 44(10). http://dx.doi.org/10.1111/jfpp.14782
    » http://dx.doi.org/10.1111/jfpp.14782
  • Ali, E., Orfi, J., AlAnsary, H., Soukane, S., Elcik, H., Alpatova, A., & Ghaffour, N. (2021). Cost analysis of multiple effect evaporation and membrane distillation hybrid desalination system. Desalination, 517, 115258. http://dx.doi.org/10.1016/j.desal.2021.115258
    » http://dx.doi.org/10.1016/j.desal.2021.115258
  • Bahnasawy, A. H., & Shenana, M. E. (2010). Flux behavior and energy consumption of ultrafiltration (UF) process of milk. Australian Journal of Agricultural Engineering, 1(2), 54-65.
  • Balde, A., & Aider, M. (2016). Impact of cryoconcentration on casein micelle size distribution, micelles inter-distance, and flow behavior of skim milk during refrigerated storage. Innovative Food Science & Emerging Technologies, 34, 68-76. http://dx.doi.org/10.1016/j.ifset.2015.12.032
    » http://dx.doi.org/10.1016/j.ifset.2015.12.032
  • Balde, A., & Aïder, M. (2017). Effect of cryoconcentration, reverse osmosis and vacuum evaporation as concentration step of skim milk prior to drying on the powder properties. Powder Technology, 319, 463-471. http://dx.doi.org/10.1016/j.powtec.2017.07.016
    » http://dx.doi.org/10.1016/j.powtec.2017.07.016
  • Bando, K., Kansha, Y., Ishizuka, M., & Tsutsumi, A. (2017). Innovative freeze-drying process based on self-heat recuperation technology. Journal of Cleaner Production, 168, 1244-1250. http://dx.doi.org/10.1016/j.jclepro.2017.09.088
    » http://dx.doi.org/10.1016/j.jclepro.2017.09.088
  • Barros, E. L. S., Silva, C. C., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudencio, E. S. (2022a). Effect of replacement of milk by block freeze concentrated whey in physicochemical and rheological properties of ice cream. Food Science and Technology, 42, e12521. http://dx.doi.org/10.1590/fst.12521
    » http://dx.doi.org/10.1590/fst.12521
  • Barros, E. L. S., Silva, C. C., Verruck, S., Canella, M. H. M., Maran, B. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). Concentrated whey from block freeze concentration or milk-based ice creams on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. Food Science and Technology, 42, e84021. http://dx.doi.org/10.1590/fst.84021
    » http://dx.doi.org/10.1590/fst.84021
  • Benedetti, S., Prudêncio, E. S., Nunes, G. L., Guizoni, K., Fogaça, L. A., & Petrus, J. C. C. (2015). Antioxidant properties of tofu whey concentrate by freeze concentration and nanofiltration processes. Journal of Food Engineering, 160, 49-55. http://dx.doi.org/10.1016/j.jfoodeng.2015.03.021
    » http://dx.doi.org/10.1016/j.jfoodeng.2015.03.021
  • Bienvenue, A., Jiménez-Flores, R., & Singh, H. (2003). Rheological properties of concentrated skim milk: importance of soluble minerals in the changes in viscosity during storage. Journal of Dairy Science, 86(12), 3813-3821. http://dx.doi.org/10.3168/jds.S0022-0302(03)73988-5 PMid:14740815.
    » http://dx.doi.org/10.3168/jds.S0022-0302(03)73988-5
  • Birchal, V., Passos, M. L., Wildhagen, G., & Mujumdar, A. (2005). Effect of spray-dryer operating variables on the whole milk powder quality. Drying Technology, 23(3), 611-636. http://dx.doi.org/10.1081/DRT-200054153
    » http://dx.doi.org/10.1081/DRT-200054153
  • Bista, A., McCarthy, N., O’Donnell, C. P., & O’Shea, N. (2021). Key parameters and strategies to control milk concentrate viscosity in milk powder manufacture. International Dairy Journal, 121, 105120. http://dx.doi.org/10.1016/j.idairyj.2021.105120
    » http://dx.doi.org/10.1016/j.idairyj.2021.105120
  • Camelo-Silva, C., Barros, E. L. S., Canella, M. H. M., Verruck, S., Prestes, A. A., Vargas, M. O., Maran, B. M., Esmerino, E. A., Silva, R., Balthazar, C. F., Calado, V. M. A., & Prudêncio, E. S. (2022a). Application of skimmed milk freeze concentrated in production of ice cream: physical, chemical, structural and rheological properties. Food Science and Technology, 42, e12221. http://dx.doi.org/10.1590/fst.12221
    » http://dx.doi.org/10.1590/fst.12221
  • Camelo-Silva, C., Barros, E. L. S., Verruck, S., Maran, B. M., Canella, M. H. M., Esmerino, E. A., Silva, R., & Prudencio, E. S. (2022b). How ice cream manufactured with concentrated milk serves as a protective probiotic carrier? An in vitro gastrointestinal assay. Food Science and Technology, 42, e28621. http://dx.doi.org/10.1590/fst.28621
    » http://dx.doi.org/10.1590/fst.28621
  • Canella, M. H. M., Dantas, A., Blanco, M., Raventós, M., Hernandez, E., & Prudencio, E. S. (2020). Optimization of goat milk vacuum-assisted block freeze concentration using response surface methodology and NaCl addition influence. LWT, 124, 109133. http://dx.doi.org/10.1016/j.lwt.2020.109133
    » http://dx.doi.org/10.1016/j.lwt.2020.109133
  • Canella, M. H. M., Muñoz, I. B., Pinto, S. S., Liz, G. R., Müller, C. M. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). Use of concentrated whey by freeze concentration process to obtain a symbiotic fermented lactic beverage. Advance Journal of Food Science and Technology, 14(2), 56-68. http://dx.doi.org/10.19026/ajfst.14.5832
    » http://dx.doi.org/10.19026/ajfst.14.5832
  • Carter, B. G., Cheng, N., Kapoor, R., Meletharayil, G. H., & Drake, M. A. (2021). Invited review: microfiltration-derived casein and whey proteins from milk. Journal of Dairy Science, 104(3), 2465-2479. http://dx.doi.org/10.3168/jds.2020-18811 PMid:33455742.
    » http://dx.doi.org/10.3168/jds.2020-18811
  • Casas-Forero, N., Orellana-Palma, P., & Petzold, G. (2020). Influence of block freeze concentration and evaporation on physicochemical properties, bioactive compounds and antioxidant activity in blueberry juice. Food Science and Technology, 40(Suppl. 2), 387-394. http://dx.doi.org/10.1590/fst.29819
    » http://dx.doi.org/10.1590/fst.29819
  • Chabarov, A., & Aider, M. (2014). Mathematical modeling and experimental validation of the mass transfer during unidirectional progressive cryoconcentration of skim milk. Innovative Food Science & Emerging Technologies, 21, 151-159. http://dx.doi.org/10.1016/j.ifset.2013.08.001
    » http://dx.doi.org/10.1016/j.ifset.2013.08.001
  • Cheng, F., Zhou, X., & Liu, Y. (2018). Methods for improvement of the thermal efficiency during spray drying. E3S Web of Conferences, 53, 01031. http://dx.doi.org/10.1051/e3sconf/20185301031
    » http://dx.doi.org/10.1051/e3sconf/20185301031
  • Coppola, L. E., Molitor, M. S., Rankin, S. A., & Lucey, J. A. (2014). Comparison of milk-derived whey protein concentrates containing various levels of casein. International Journal of Dairy Technology, 67(4), 467-473. http://dx.doi.org/10.1111/1471-0307.12157
    » http://dx.doi.org/10.1111/1471-0307.12157
  • Dantas, A., Quinteros, G. J., Darvishvand, S. Y., Blanco, M., Hernandez, E., Prudencio, E. S., & Samsuri, S. (2021). The combined use of progressive and block freeze concentration in lactose‐free milk: effect of process parameters and influence on the content of carbohydrates and proteins. Journal of Food Process Engineering, 44(11). http://dx.doi.org/10.1111/jfpe.13867
    » http://dx.doi.org/10.1111/jfpe.13867
  • Deeth, H., & Bansal, N. (2019). Whey proteins: an overview. In H.C. Deeth & N. Bansal (Eds.), Whey proteins: from milk to medicine (pp. 1-50). London: Elsevier. http://dx.doi.org/10.1016/B978-0-12-812124-5.00001-1
    » http://dx.doi.org/10.1016/B978-0-12-812124-5.00001-1
  • Deshwal, G. K., Singh, A. K., Kumar, D., & Sharma, H. (2020). Effect of spray and freeze drying on physico-chemical, functional, moisture sorption and morphological characteristics of camel milk powder. LWT, 134, 110117. http://dx.doi.org/10.1016/j.lwt.2020.110117
    » http://dx.doi.org/10.1016/j.lwt.2020.110117
  • Ding, H., Wilson, D. I., Yu, W., & Young, B. R. (2021a). An investigation of the relative impact of process and shape factor variables on milk powder quality. Food and Bioproducts Processing, 126, 62-72. http://dx.doi.org/10.1016/j.fbp.2020.12.010
    » http://dx.doi.org/10.1016/j.fbp.2020.12.010
  • Ding, Z., Qin, F. G. F., Peng, K., Yuan, J., Huang, S., Jiang, R., & Shao, Y. (2021b). Heat and mass transfer of scraped surface heat exchanger used for suspension freeze concentration. Journal of Food Engineering, 288, 110141. http://dx.doi.org/10.1016/j.jfoodeng.2020.110141
    » http://dx.doi.org/10.1016/j.jfoodeng.2020.110141
  • Duan, X., Yang, X., Ren, G., Pang, Y., Liu, L., & Liu, Y. (2016). Technical aspects in freeze-drying of foods. Drying Technology, 34(11), 1271-1285. http://dx.doi.org/10.1080/07373937.2015.1099545
    » http://dx.doi.org/10.1080/07373937.2015.1099545
  • Dumpler, J., & Kulozik, U. (2015). Heat stability of concentrated skim milk as a function of heating time and temperature on a laboratory scale – improved methodology and kinetic relationship. International Dairy Journal, 49, 111-117. http://dx.doi.org/10.1016/j.idairyj.2015.05.005
    » http://dx.doi.org/10.1016/j.idairyj.2015.05.005
  • Dumpler, J., & Kulozik, U. (2016). Heat-induced coagulation of concentrated skim milk heated by direct steam injection. International Dairy Journal, 59, 62-71. http://dx.doi.org/10.1016/j.idairyj.2016.03.009
    » http://dx.doi.org/10.1016/j.idairyj.2016.03.009
  • Dumpler, J., Huppertz, T., & Kulozik, U. (2020). Invited review: heat stability of milk and concentrated milk: past, present, and future research objectives. Journal of Dairy Science, 103(12), 10986-11007. http://dx.doi.org/10.3168/jds.2020-18605 PMid:33041027.
    » http://dx.doi.org/10.3168/jds.2020-18605
  • Dumpler, J., Peraus, F., Depping, V., Stefánsdóttir, B., Grunow, M., & Kulozik, U. (2018). Modelling of heat stability and heat-induced aggregation of casein micelles in concentrated skim milk using a Weibullian model. International Journal of Dairy Technology, 71(3), 601-612. http://dx.doi.org/10.1111/1471-0307.12501
    » http://dx.doi.org/10.1111/1471-0307.12501
  • Faion, A. M., Becker, J., Fernandes, I. A., Steffens, J., & Valduga, E. (2019). Sheep’s milk concentration by ultrafiltration and cheese elaboration. Journal of Food Process Engineering, 42(4). http://dx.doi.org/10.1111/jfpe.13058
    » http://dx.doi.org/10.1111/jfpe.13058
  • Faucher, M., Perreault, V., Ciftci, O. N., Gaaloul, S., & Bazinet, L. (2021). Phospholipid recovery from sweet whey and whey protein concentrate: use of electrodialysis with bipolar membrane combined with a dilution factor as an ecoefficient method. Future Foods, 4, 100052. http://dx.doi.org/10.1016/j.fufo.2021.100052
    » http://dx.doi.org/10.1016/j.fufo.2021.100052
  • Feeney, E. L., Lamichhane, P., & Sheehan, J. J. (2021). The cheese matrix: understanding the impact of cheese structure on aspects of cardiovascular health – a food science and a human nutrition perspective. International Journal of Dairy Technology, 74(4), 656-670. http://dx.doi.org/10.1111/1471-0307.12755
    » http://dx.doi.org/10.1111/1471-0307.12755
  • Feng, D., Wang, J., Ji, X., Min, W., & Yan, W. (2021). HS-GC-IMS detection of volatile organic compounds in yak milk powder processed by different drying methods. LWT, 141, 110855. http://dx.doi.org/10.1016/j.lwt.2021.110855
    » http://dx.doi.org/10.1016/j.lwt.2021.110855
  • Fernández-Seara, J., & Pardiñas, Á. Á. (2014). Refrigerant falling film evaporation review: description, fluid dynamics and heat transfer. Applied Thermal Engineering, 64(1-2), 155-171. http://dx.doi.org/10.1016/j.applthermaleng.2013.11.023
    » http://dx.doi.org/10.1016/j.applthermaleng.2013.11.023
  • Fialho, T. L., Martins, E., Silva, C. R. J., Stephani, R., Tavares, G. M., Silveira, A. C. P., Perrone, Í. T., Schuck, P., Oliveira, L. F. C., & Carvalho, A. F. (2018). Lactose-hydrolyzed milk powder: physicochemical and technofunctional characterization. Drying Technology, 36(14), 1688-1695. http://dx.doi.org/10.1080/07373937.2017.1421551
    » http://dx.doi.org/10.1080/07373937.2017.1421551
  • Fox, P. F., Uniacke-Lowe, T., McSweeney, P. L. H., & O’Mahony, J. A. (2015). Dairy chemistry and biochemistry Cham: Springer International Publishing. Heat-induced changes in milk (pp. 345-375).
  • France, T. C., Bot, F., Kelly, A. L., Crowley, S. V., & O’Mahony, J. A. (2021). The influence of temperature on filtration performance and fouling during cold microfiltration of skim milk. Separation and Purification Technology, 262, 118256. http://dx.doi.org/10.1016/j.seppur.2020.118256
    » http://dx.doi.org/10.1016/j.seppur.2020.118256
  • Galvão, D. F. (2018). Membrane technology and water reuse in a dairy industry. In N. Koca (Ed.), Technological approaches for novel applications in dairy processing London: IntechOpen. http://dx.doi.org/10.5772/intechopen.76464
    » http://dx.doi.org/10.5772/intechopen.76464
  • Garcia-Amezquita, L. E., Welti-Chanes, J., Vergara-Balderas, F. T., & Bermúdez-Aguirre, D. (2016). Freeze-drying: the basic process. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 104-109). Oxford: Elsevier. http://dx.doi.org/10.1016/B978-0-12-384947-2.00328-7
    » http://dx.doi.org/10.1016/B978-0-12-384947-2.00328-7
  • Guichet, V., & Jouhara, H. (2020). Condensation, evaporation and boiling of falling films in wickless heat pipes (two-phase closed thermosyphons): a critical review of correlations. International Journal of Thermofluids, 1-2, 100001. http://dx.doi.org/10.1016/j.ijft.2019.100001
    » http://dx.doi.org/10.1016/j.ijft.2019.100001
  • Habtegebriel, H., Edward, D., Wawire, M., Sila, D., & Seifu, E. (2018). Effect of operating parameters on the surface and physico-chemical properties of spray-dried camel milk powders. Food and Bioproducts Processing, 112, 137-149. http://dx.doi.org/10.1016/j.fbp.2018.09.010
    » http://dx.doi.org/10.1016/j.fbp.2018.09.010
  • Henriques, M. H. F., Gomes, D. M. G. S., Borges, A. R., & Pereira, C. J. D. (2020). Liquid whey protein concentrates as primary raw material for acid dairy gels. Food Science and Technology, 40(2), 361-369. http://dx.doi.org/10.1590/fst.43218
    » http://dx.doi.org/10.1590/fst.43218
  • Jouki, M., Khazaei, N., Rezaei, F., & Taghavian-Saeid, R. (2021). Production of synbiotic freeze-dried yoghurt powder using microencapsulation and cryopreservation of L. plantarum in alginate-skim milk microcapsules. International Dairy Journal, 122, 105133. http://dx.doi.org/10.1016/j.idairyj.2021.105133
    » http://dx.doi.org/10.1016/j.idairyj.2021.105133
  • Jukkola, A., Partanen, R., Rojas, O. J., & Heino, A. (2018). Effect of heat treatment and pH on the efficiency of micro-diafiltration for the separation of native fat globules from cream in butter production. Journal of Membrane Science, 548, 99-107. http://dx.doi.org/10.1016/j.memsci.2017.11.012
    » http://dx.doi.org/10.1016/j.memsci.2017.11.012
  • Kalyankar, S. D., Deshmukh, M. A., Chopde, S. S., Khedkar, C. D., Lule, V. K., & Deosarkar, S. S. (2015). Milk powder. In B. Caballero, P. M. Finglas & F. Toldrá (Eds.), Encyclopedia of food and health (pp. 724-728). Burlington: Elsevier.
  • Keselj, K., Pavkov, I., Radojcin, M., & Stamenkovic, Z. (2017). Comparison of energy consumption in the convective and freeze drying of raspberries. Journal on Processing and Energy in Agriculture, 21(4), 192-196. http://dx.doi.org/10.5937/JPEA1704192K
    » http://dx.doi.org/10.5937/JPEA1704192K
  • Khan, A., Munir, M. T., Yu, W., & Young, B. R. (2021). Near‐infrared spectroscopy and data analysis for predicting milk powder quality attributes. International Journal of Dairy Technology, 74(1), 235-245. http://dx.doi.org/10.1111/1471-0307.12734
    » http://dx.doi.org/10.1111/1471-0307.12734
  • Kim, S.-H., & Min, C.-S. (2019). Fouling reduction using the resonance vibration in membrane separation of whole milk. Journal of Industrial and Engineering Chemistry, 75, 123-129. http://dx.doi.org/10.1016/j.jiec.2019.03.011
    » http://dx.doi.org/10.1016/j.jiec.2019.03.011
  • Koutina, G., & Skibsted, L. H. (2015). Calcium and phosphorus equilibria during acidification of skim milk at elevated temperature. International Dairy Journal, 45, 1-7. http://dx.doi.org/10.1016/j.idairyj.2015.01.006
    » http://dx.doi.org/10.1016/j.idairyj.2015.01.006
  • Lin, Y., Kelly, A. L., O’Mahony, J. A., & Guinee, T. P. (2018). Effect of heat treatment, evaporation and spray drying during skim milk powder manufacture on the compositional and processing characteristics of reconstituted skim milk and concentrate. International Dairy Journal, 78, 53-64. http://dx.doi.org/10.1016/j.idairyj.2017.10.007
    » http://dx.doi.org/10.1016/j.idairyj.2017.10.007
  • Liz, G. R., Verruck, S., Canella, M. H. M., Dantas, A., Garcia, S. G., Maran, B. M., Murakami, F. S., & Prudencio, E. S. (2020). Stability of bifidobacteria entrapped in goat’s whey freeze concentrate and inulin as wall materials and powder properties. Food Research International, 127, 108752. http://dx.doi.org/10.1016/j.foodres.2019.108752 PMid:31882096.
    » http://dx.doi.org/10.1016/j.foodres.2019.108752
  • Ma, Y., Ryan, C., Barbano, D. M., Galton, D. M., Rudan, M. A., & Boor, K. J. (2000). Effects of somatic cell count on quality and shelf-life of pasteurized fluid milk. Journal of Dairy Science, 83(2), 264-274. http://dx.doi.org/10.3168/jds.S0022-0302(00)74873-9 PMid:10714859.
    » http://dx.doi.org/10.3168/jds.S0022-0302(00)74873-9
  • Magenis, R. B., Prudêncio, E. S., Amboni, R. D. M. C., Cerqueira, N. G. Jr., Oliveira, R. V. B., Soldi, V., & Benedet, H. D. (2006). Compositional and physical properties of yogurts manufactured from milk and whey cheese concentrated by ultrafiltration. International Journal of Food Science & Technology, 41(5), 560-568. http://dx.doi.org/10.1111/j.1365-2621.2005.01100.x
    » http://dx.doi.org/10.1111/j.1365-2621.2005.01100.x
  • Marx, M., & Kulozik, U. (2018). Thermal denaturation kinetics of whey proteins in reverse osmosis and nanofiltration sweet whey concentrates. International Dairy Journal, 85, 270-279. http://dx.doi.org/10.1016/j.idairyj.2018.04.009
    » http://dx.doi.org/10.1016/j.idairyj.2018.04.009
  • Marx, M., Bernauer, S., & Kulozik, U. (2018). Manufacturing of reverse osmosis whey concentrates with extended shelf life and high protein nativity. International Dairy Journal, 86, 57-64. http://dx.doi.org/10.1016/j.idairyj.2018.06.019
    » http://dx.doi.org/10.1016/j.idairyj.2018.06.019
  • Masum, A. K. M., Chandrapala, J., Huppertz, T., Adhikari, B., & Zisu, B. (2020). Influence of drying temperatures and storage parameters on the physicochemical properties of spray-dried infant milk formula powders. International Dairy Journal, 105, 104696. http://dx.doi.org/10.1016/j.idairyj.2020.104696
    » http://dx.doi.org/10.1016/j.idairyj.2020.104696
  • Merkel, A., Voropaeva, D., & Ondrušek, M. (2021). The impact of integrated nanofiltration and electrodialytic processes on the chemical composition of sweet and acid whey streams. Journal of Food Engineering, 298, 110500. http://dx.doi.org/10.1016/j.jfoodeng.2021.110500
    » http://dx.doi.org/10.1016/j.jfoodeng.2021.110500
  • Mikhaylin, S., Nikonenko, V., Pourcelly, G., & Bazinet, L. (2016). Hybrid bipolar membrane electrodialysis/ultrafiltration technology assisted by a pulsed electric field for casein production. Green Chemistry, 18(1), 307-314. http://dx.doi.org/10.1039/C5GC00970G
    » http://dx.doi.org/10.1039/C5GC00970G
  • Mikhaylin, S., Patouillard, L., Margni, M., & Bazinet, L. (2018). Milk protein production by a more environmentally sustainable process: bipolar membrane electrodialysis coupled with ultrafiltration. Green Chemistry, 20(2), 449-456. http://dx.doi.org/10.1039/C7GC02154B
    » http://dx.doi.org/10.1039/C7GC02154B
  • Moejes, S. N., van Wonderen, G. J., Bitter, J. H., & van Boxtel, A. J. B. (2020). Assessment of air gap membrane distillation for milk concentration. Journal of Membrane Science, 594, 117403. http://dx.doi.org/10.1016/j.memsci.2019.117403
    » http://dx.doi.org/10.1016/j.memsci.2019.117403
  • Moharramzadeh, S., Ong, S. K., Alleman, J., & Cetin, K. S. (2021). Parametric study of the progressive freeze concentration for desalination. Desalination, 510, 115077. http://dx.doi.org/10.1016/j.desal.2021.115077
    » http://dx.doi.org/10.1016/j.desal.2021.115077
  • Morison, K. R., & Hartel, R. W. (2018). Evaporation and freeze concentration. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 495-550). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-9
    » http://dx.doi.org/10.1201/9780429449734-9
  • Muñoz, I. B., Rubio, A., Blanco, M., Raventós, M., Hernández, E., & Prudêncio, E. S. (2019). Progressive freeze concentration of skimmed milk in an agitated vessel: effect of the coolant temperature and stirring rate on process performance. Food Science & Technology International, 25(2), 150-159. http://dx.doi.org/10.1177/1082013218803263 PMid:30286622.
    » http://dx.doi.org/10.1177/1082013218803263
  • Muñoz, I. B., Verruck, S., Canella, M. H. M., Dias, C. O., Amboni, R. D. M. C., & Prudencio, E. S. (2018). The use of soft fresh cheese manufactured from freeze concentrated milk as a novelty protective matrix on Bifidobacterium BB-12 survival under in vitro simulated gastrointestinal conditions. LWT, 97, 725-729. http://dx.doi.org/10.1016/j.lwt.2018.08.009
    » http://dx.doi.org/10.1016/j.lwt.2018.08.009
  • Musina, O., Rashidinejad, A., Putnik, P., Barba, F. J., Abbaspourrad, A., Greiner, R., & Roohinejad, S. (2018). The use of whey protein extract for manufacture of a whipped frozen dairy dessert. Mljekarstvo, 68(4), 254-271. http://dx.doi.org/10.15567/mljekarstvo.2018.0402
    » http://dx.doi.org/10.15567/mljekarstvo.2018.0402
  • Ojeda, A., Moreno, F. L., Ruiz, R. Y., Blanco, M., Raventós, M., & Hernández, E. (2017). Effect of process parameters on the progressive freeze concentration of sucrose solutions. Chemical Engineering Communications, 204(8), 951-956. http://dx.doi.org/10.1080/00986445.2017.1328413
    » http://dx.doi.org/10.1080/00986445.2017.1328413
  • Park, C. W., Stout, M. A., & Drake, M. (2016). The effect of spray-drying parameters on the flavor of nonfat dry milk and milk protein concentrate 70%. Journal of Dairy Science, 99(12), 9598-9610. http://dx.doi.org/10.3168/jds.2016-11692 PMid:27743674.
    » http://dx.doi.org/10.3168/jds.2016-11692
  • Perusko, M., Ghnimi, S., Simovic, A., Stevanovic, N., Radomirovic, M., Gharsallaoui, A., Smiljanic, K., Van Haute, S., Stanic-Vucinic, D., & Velickovic, T. C. (2021). Maillard reaction products formation and antioxidative power of spray dried camel milk powders increases with the inlet temperature of drying. LWT, 143, 111091. http://dx.doi.org/10.1016/j.lwt.2021.111091
    » http://dx.doi.org/10.1016/j.lwt.2021.111091
  • Petzold, P. O. G., Orellana, P., Moreno, J. J., Junod, J., & Bugueño, G. (2016). Freeze concentration as a technique to protect valuable heat-labile components of foods. In J. J. Moreno (Ed.), Innovative processing technologies for foods with bioactive compounds (pp. 183-192). Boca Raton: Taylor & Francis Group.
  • Prestes, A. A., Helm, C. V., Esmerino, E. A., Silva, R., Cruz, A. G., & Prudencio, E. S. (2022). Freeze concentration techniques as alternative methods to thermal processing in dairy manufacturing: a review. Journal of Food Science, 87(2), 488-502. http://dx.doi.org/10.1111/1750-3841.16027 PMid:35049054.
    » http://dx.doi.org/10.1111/1750-3841.16027
  • Prestes, A. A., Verruck, S., Vargas, M. O., Canella, M. H. M., Silva, C. C., Barros, E. L. S., Dantas, A., Oliveira, L. V. A., Maran, B. M., Matos, M., Helm, C. V., & Prudencio, E. S. (2021). Influence of guabiroba pulp (campomanesia xanthocarpa o. berg) added to fermented milk on probiotic survival under in vitro simulated gastrointestinal conditions. Food Research International, 141, 110135. http://dx.doi.org/10.1016/j.foodres.2021.110135 PMid:33642002.
    » http://dx.doi.org/10.1016/j.foodres.2021.110135
  • Prudêncio, E. S., Müller, C. M. O., Fritzen-Freire, C. B., Amboni, R. D. M. C., & Petrus, J. C. C. (2014). Effect of whey nanofiltration process combined with diafiltration on the rheological and physicochemical properties of ricotta cheese. Food Research International, 56, 92-99. http://dx.doi.org/10.1016/j.foodres.2013.12.017
    » http://dx.doi.org/10.1016/j.foodres.2013.12.017
  • Ramírez, C. A., Patel, M., & Blok, K. (2006). From fluid milk to milk powder: energy use and energy efficiency in the European dairy industry. Energy, 31(12), 1984-2004. http://dx.doi.org/10.1016/j.energy.2005.10.014
    » http://dx.doi.org/10.1016/j.energy.2005.10.014
  • Rao, M. A. (2018). Transport and storage of food products. In D. R. Heldman & D. B. Lund (Eds.), Handbook of food engineering (2nd ed., pp. 354-394). Boca Raton: Taylor & Francis Group. http://dx.doi.org/10.1201/9780429449734-5
    » http://dx.doi.org/10.1201/9780429449734-5
  • Rongsirikul, N., & Hongsprabhas, P. (2016). Brown pigment formation in heated sugar–protein mixed suspensions containing unmodified and peptically modified whey protein concentrates. Journal of Food Science and Technology, 53(1), 800-807. http://dx.doi.org/10.1007/s13197-015-1955-4 PMid:26788001.
    » http://dx.doi.org/10.1007/s13197-015-1955-4
  • Saboyainsta, L. V., & Maubois, J.-L. (2000). Current developments of microfiltration technology in the dairy industry. Le Lait, 80(6), 541-553. http://dx.doi.org/10.1051/lait:2000144
    » http://dx.doi.org/10.1051/lait:2000144
  • Samsuri, S., Amran, N. A., & Jusoh, M. (2018). Modelling of heat transfer for progressive freeze concentration process by spiral finned crystallizer. Chinese Journal of Chemical Engineering, 26(5), 970-975. http://dx.doi.org/10.1016/j.cjche.2017.09.025
    » http://dx.doi.org/10.1016/j.cjche.2017.09.025
  • Sánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011a). Review: freeze concentration technology applied to dairy products. Food Science & Technology International, 17(1), 5-13. http://dx.doi.org/10.1177/1082013210382479 PMid:21364040.
    » http://dx.doi.org/10.1177/1082013210382479
  • Sánchez, J., Hernández, E., Auleda, J. M., & Raventós, M. (2011b). Freeze concentration of whey in a falling-film based pilot plant: process and characterization. Journal of Food Engineering, 103(2), 147-155. http://dx.doi.org/10.1016/j.jfoodeng.2010.10.009
    » http://dx.doi.org/10.1016/j.jfoodeng.2010.10.009
  • Sánchez, J., Ruiz, Y., Raventós, M., Auleda, J. M., & Hernández, E. (2010). Progressive freeze concentration of orange juice in a pilot plant falling film. Innovative Food Science & Emerging Technologies, 11(4), 644-651. http://dx.doi.org/10.1016/j.ifset.2010.06.006
    » http://dx.doi.org/10.1016/j.ifset.2010.06.006
  • Schäfer, J., Bast, R., Atamer, Z., Nöbel, S., Kohlus, R., & Hinrichs, J. (2018). Concentration of skim milk by means of dynamic filtration using overlapping rotating ceramic membrane disks. International Dairy Journal, 78, 11-19. http://dx.doi.org/10.1016/j.idairyj.2017.10.004
    » http://dx.doi.org/10.1016/j.idairyj.2017.10.004
  • Schuck, P., Jeantet, R., Tanguy, G., Méjean, S., Gac, A., Lefebvre, T., Labussière, E., & Martineau, C. (2015). Energy consumption in the processing of dairy and feed powders by evaporation and drying. Drying Technology, 33(2), 176-184. http://dx.doi.org/10.1080/07373937.2014.942913
    » http://dx.doi.org/10.1080/07373937.2014.942913
  • Shabbir, M. A., Ahmed, H., Maan, A. A., Rehman, A., Afraz, M. T., Iqbal, M. W., Khan, I. M., Amir, R. M., Ashraf, W., Khan, M. R., & Aadil, R. M. (2021). Effect of non-thermal processing techniques on pathogenic and spoilage microorganisms of milk and milk products. Food Science and Technology, 41(2), 279-294. http://dx.doi.org/10.1590/fst.05820
    » http://dx.doi.org/10.1590/fst.05820
  • Silva, S. H., Neves, I. C. O., Meira, A. C. F. O., Alexandre, A. C. S., Oliveira, N. L., & Resende, J. V. (2021). Freeze-dried petit suisse cheese produced with ora-pro-nóbis (Pereskia aculeata Miller) biopolymer and carrageenan mix. LWT, 149, 111764. http://dx.doi.org/10.1016/j.lwt.2021.111764
    » http://dx.doi.org/10.1016/j.lwt.2021.111764
  • Smith, K. (2013). Development of membrane processes. In A. Y. Tamime (Ed.), Membrane processing: dairy and beverage application (pp. 1-9). Chichester: Wiley-Blackwell.
  • Stratakos, A. C., Inguglia, E. S., Linton, M., Tollerton, J., Murphy, L., Corcionivoschi, N., Koidis, A., & Tiwari, B. K. (2019). Effect of high pressure processing on the safety, shelf life and quality of raw milk. Innovative Food Science & Emerging Technologies, 52, 325-333. http://dx.doi.org/10.1016/j.ifset.2019.01.009
    » http://dx.doi.org/10.1016/j.ifset.2019.01.009
  • Tanguy, G., Dolivet, A., Garnier-Lambrouin, F., Méjean, S., Coffey, D., Birks, T., Jeantet, R., & Schuck, P. (2015). Concentration of dairy products using a thin film spinning cone evaporator. Journal of Food Engineering, 166, 356-363. http://dx.doi.org/10.1016/j.jfoodeng.2015.07.001
    » http://dx.doi.org/10.1016/j.jfoodeng.2015.07.001
  • Tari, N. R., Gaygadzhiev, Z., Guri, A., & Wright, A. (2021). Effect of pH and heat treatment conditions on physicochemical and acid gelation properties of liquid milk protein concentrate. Journal of Dairy Science, 104(6), 6609-6619. http://dx.doi.org/10.3168/jds.2020-19355 PMid:33773779.
    » http://dx.doi.org/10.3168/jds.2020-19355
  • Tribst, A. A. L., Falcade, L. T. P., Carvalho, N. S., Cristianini, M., Leite, B. R. C. Jr., & Oliveira, M. M. (2020). Using physical processes to improve physicochemical and structural characteristics of fresh and frozen/thawed sheep milk. Innovative Food Science & Emerging Technologies, 59, 102247. http://dx.doi.org/10.1016/j.ifset.2019.102247
    » http://dx.doi.org/10.1016/j.ifset.2019.102247
  • Valencia, A. P., Doyen, A., Benoit, S., Margni, M., & Pouliot, Y. (2018). Effect of ultrafiltration of milk prior to fermentation on mass balance and process efficiency in Greek-style yogurt manufacture. Foods, 7(9), 144. http://dx.doi.org/10.3390/foods7090144 PMid:30181438.
    » http://dx.doi.org/10.3390/foods7090144
  • Vargas, M. O., Prestes, A. A., Miotto, M., & Prudêncio, E. S. (2021). Dulce de leche: product types, production processes, quality aspects and innovations minor EDITS. International Journal of Dairy Technology, 74(2), 262-276. http://dx.doi.org/10.1111/1471-0307.12762
    » http://dx.doi.org/10.1111/1471-0307.12762
  • Velpula, S. (2017). Dairy wastewater treatment by membrane systems - a review. International Journal of Pure & Applied Bioscience, 5(6), 389-395. http://dx.doi.org/10.18782/2320-7051.5540
    » http://dx.doi.org/10.18782/2320-7051.5540
  • Verdurmen, R. E. M., & Jong, P. (2003). Optimising product quality and process control for powdered dairy products. In G. Smit (Ed.), Dairy processing (pp. 333-365). Cambridge: Woodhead Publishing. http://dx.doi.org/10.1533/9781855737075.2.333
    » http://dx.doi.org/10.1533/9781855737075.2.333
  • Verruck, S., Balthazar, C. F., Rocha, R. S., Silva, R., Esmerino, E. A., Pimentel, T. C., Freitas, M. Q., Silva, M. C., Cruz, A. G., & Prudencio, E. S. (2019a). Dairy foods and positive impact on the consumer’s health. In F. Toldrá (Ed.), Advances in food and nutrition research (Vol. 89, pp. 95-164). Cambridge: Elsevier.
  • Verruck, S., Sartor, S., Marenda, F. B., Barros, E. L. S., Camelo-Silva, C., Canella, M. H. M., & Prudencio, E. S. (2019b). Influence of heat treatment and microfiltration on the milk proteins properties. Advances in Food Technology and Nutritional Sciences – Open Journal, 5(2), 54-66. http://dx.doi.org/10.17140/AFTNSOJ-5-157
    » http://dx.doi.org/10.17140/AFTNSOJ-5-157
  • Vincenzetti, S., Cecchi, T., Perinelli, D. R., Pucciarelli, S., Polzonetti, V., Bonacucina, G., Ariani, A., Parrocchia, L., Spera, D. M., Ferretti, E., Vallesi, P., & Polidori, P. (2018). Effects of freeze-drying and spray-drying on donkey milk volatile compounds and whey proteins stability. LWT, 88, 189-195. http://dx.doi.org/10.1016/j.lwt.2017.10.019
    » http://dx.doi.org/10.1016/j.lwt.2017.10.019
  • Waghmare, R. B., Perumal, A. B., Moses, J. A., & Anandharamakrishnan, C. (2021). Recent developments in freeze drying of foods. In K. Knoerzer & K. Muthukumarappan (Eds.), Innovative food processing technologies: a comprehensive review (pp. 82-99). Amsterdam: Elsevier. http://dx.doi.org/10.1016/B978-0-12-815781-7.00017-2
    » http://dx.doi.org/10.1016/B978-0-12-815781-7.00017-2
  • Wu, J., Li, H., A’yun, Q., Doost, A. S., Meulenaer, B., & Van der Meeren, P. (2021). Conjugation of milk proteins and reducing sugars and its potential application in the improvement of the heat stability of (recombined) evaporated milk. Trends in Food Science & Technology, 108, 287-296. http://dx.doi.org/10.1016/j.tifs.2021.01.019
    » http://dx.doi.org/10.1016/j.tifs.2021.01.019
  • Yao, Y., Zhao, G., Yan, Y., Chen, C., Sun, C., Zou, X., Jin, Q., & Wang, X. (2016). Effects of freeze drying and spray drying on the microstructure and composition of milk fat globules. RSC Advances, 6(4), 2520-2529. http://dx.doi.org/10.1039/C5RA22323G
    » http://dx.doi.org/10.1039/C5RA22323G
  • Zambrano, A., Ruiz, Y., Hernández, E., Raventós, M., & Moreno, F. L. (2018). Freeze desalination by the integration of falling film and block freeze-concentration techniques. Desalination, 436, 56-62. http://dx.doi.org/10.1016/j.desal.2018.02.015
    » http://dx.doi.org/10.1016/j.desal.2018.02.015
  • Zhou, Z., & Langrish, T. (2021). A review of Maillard reactions in spray dryers. Journal of Food Engineering, 305, 110615. http://dx.doi.org/10.1016/j.jfoodeng.2021.110615
    » http://dx.doi.org/10.1016/j.jfoodeng.2021.110615
  • Zhu, D., & Damodaran, S. (2011). Composition, thermotropic properties, and oxidative stability of freeze-dried and spray-dried milk fat globule membrane isolated from cheese whey. Journal of Agricultural and Food Chemistry, 59(16), 8931-8938. http://dx.doi.org/10.1021/jf201688w PMid:21766876.
    » http://dx.doi.org/10.1021/jf201688w
  • Zhu, D., Kebede, B., Chen, G., McComb, K., & Frew, R. (2020). Impact of freeze-drying and subsequent storage on milk metabolites based on 1H NMR and UHPLC-QToF/MS. Food Control, 116, 107017. http://dx.doi.org/10.1016/j.foodcont.2019.107017
    » http://dx.doi.org/10.1016/j.foodcont.2019.107017

Publication Dates

  • Publication in this collection
    15 Apr 2022
  • Date of issue
    2022

History

  • Received
    05 Jan 2022
  • Accepted
    16 Feb 2022
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