conventional concentration processes
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Evaporation |
-The most practical milk concentration approach; |
- High temperatures may decrease milk bioactive compounds (vitamins, enzymes, proteins); |
3200 kJ.kg-1 water removed (single- effect evaporator under partial vacuum and under atmospheric pressure at boiling temperature); |
- Low energy costs using multi-stages evaporators; |
- Denaturation of milk proteins may result in heat-induced fouling inside of evaporators; |
900 kJ.kg-1 (pilot-scale roller dryers in a partial vacuum chamber with a mechanical vapor recompression heating system) (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....
) |
- Increased shelf-life |
- Intense heat treatment can affect the pH sensibility and minerals equilibrium; |
300 kJ.kg-1 (traditional multi-stages evaporators with mechanical vapor recompression- MVR) (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....
; 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...
) |
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- In specific products, undesirable changes of sensory properties (flavor, color and texture); |
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- High installation and operating costs |
|
Spray drying |
- Increased shelf-life; |
- Decrease in milk thermolabile compounds; |
5256 kJ.kg-1 for a skim milk spray-dried from 50% to 96% total solids (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....
); |
- Lower storage and transportation costs; |
- High energy consumption (10-20 times higher than evaporation process); |
One single stage: 4900 kJ/kg water evaporated; two stages: 4300 kJ/kg; three stages 3400 kJ/kg (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....
) |
- Reduction of the product volume; |
- To reduce energy costs, there is a need for pre-concentration (90% of the water is removed in the evaporator and only 9-10% in the spray dryer) |
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-Expansion of logistic distribution; |
- Changes in the fat and lactose conformation, resulting in undesirable physicochemical and sensory characteristics |
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- Requires a noticeably short time |
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alternative concentration processes
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Freeze concentration |
- Preservation of highly heat-sensitive milk compounds; |
- High investment cost in large-scale production; |
335 kJ.kg-1 water removed (which is equivalent to approximately 15% of heat addition in a single-effect evaporator) (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...
) |
- Maintenance of color and flavor; |
- High refrigeration and operating costs; |
- Low deterioration due to decreased of enzymatic and microbiological activities; |
- Low production rate; |
- Increased shelf-life; |
- Loss of soluble solids in the ice fraction |
- Non- polluting process; |
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- Without the use of preservatives and additives; |
|
Membrane separation |
-Low energy consumption; |
- Membrane pores are often clogged; |
14.0-36.0 kJ.kg-1 water removed by pressure driven membrane filtration (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....
); |
- High flow rates; |
- Requires high quality water for cleaning; |
50.08-62.54 kJ.L-1 of milk retentate, 18.18-21.65 kJ.L-1 of permeate and 87.08-107 kJ for cleaning at different pressures (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.); |
- Improvement of the yield; |
- High maintenance costs |
0.6-1.5 kJs.kg-1 for ultrafiltration of a Greek-style yogurt (Paredes 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...
) |
- Increased shelf-life; |
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-Removal of bacterial pathogens and spores; |
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- Non-polluting process; |
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- Without the use of preservatives and additives |
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Freeze drying |
-Preservation of bioactive compounds; |
- High energy consumption; |
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-Maintenance of flavor and color; |
- Inviable to produce in large-scale; |
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- Increased shelf-life; |
- Low production rate; |
3820-5500 kJ.kg-1 water removed. In 24 h, the energy consumption of all the consumers (cooling chamber, sublimation, and vacuum pump) in a freeze-dryer is 937,177.42 kJ (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...
) |
- Facility of transport and storage; |
- Requires sterile diluents on reconstitution; |
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- Non-polluting process, low waste water; |
- High cost and complexity of the equipment |
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- Without the use of preservatives and additives; |
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-Process with absence of oxygen, preventing against oxidative reactions |
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