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Prediction of mass transfer parameters and thermodynamic properties using the refractance WindowTM technique for drying of Yam (Dioscorea Trifida) paste

Abstract

Dioscorea trifida tuber contains starch, vitamins, minerals and bioactive compounds. It is perishable, requiring dehydration treatment to increase shelf life. This study aimed to investigate the mass transfer parameters and thermodynamic properties of Dioscorea trifida using Refractance Window (RW) drying (70, 80, and 90 °C). It was observed that the dehydration process occurred in a short time (40 min). The moisture diffusivity and the mass transfer coefficient were determined using the Dincer and Dost model. The diffusivity coefficients ranged from 2.62 × 10-6 at 6.13 × 10-6 m2 s-1, the mass transfer coefficient ranged from 3.46 × 10-4 at 4.04 × 10-4 m s-1 and the estimated of activation energy was 44.091 kJ mol-1. In the Dioscorea trifida Refractance Window drying, the enthalpy and entropy are positive and negative, respectively, decreasing with increasing temperature and thus indicating that the process is endothermic. Gibbs free energy increases with increasing temperature, indicating that the process does not occur spontaneously.

Keywords:
food matrices; mathematical modeling; yam; thermodynamic properties; dincer and dost model

1 Introduction

Dioscorea trifida tuber originates from South America and occurs very frequently in the northern region of Brazil, where it is commonly known as purple yam (Castro et al., 2012Castro, A. D., Fraxe, T. J., Pereira, H. D. S., & Kinupp, V. F. (2012). Etnobotânica das variedades locais do cará (Dioscorea spp.) cultivados em comunidades no município de Caapiranga, estado do Amazonas. Acta Botanica Brasílica, 26(3), 658-667. http://dx.doi.org/10.1590/S0102-33062012000300015.
http://dx.doi.org/10.1590/S0102-33062012...
; Andres et al., 2017Andres, C., Adeoluwa, O., & Bhullar, G. S. (2017). Yam (Dioscorea spp.). In B. Thomas, B. G. Murray & D. J. Murphy (Eds.), Encyclopedia of applied plant sciences (Vol. 3, pp. 435-441). Waltham, M. A.: Academic Press.), and is abundantly available for a short period during the summer. Dioscorea trifida tubers contain a substantial amount of starch, vitamins, minerals, and important bioactive compounds (Oliveira et al., 2007Oliveira, A. P., Barbosa, L. J. N., Pereira, W. E., Silva, J. E. L., & Oliveira, A. N. P. (2007). Produção de túberas comerciais de inhame em função de doses de nitrogênio. Horticultura Brasileira, 25(1), 73-76. http://dx.doi.org/10.1590/S0102-05362007000100014.
http://dx.doi.org/10.1590/S0102-05362007...
; Ramos-Escudero et al., 2010Ramos-Escudero, F., Santos-Buelga, C., Pérez-Alonso, J. J., Yáñez, J. A., & Dueñas, M. (2010). HPLC-DAD-ESI/MS identification of anthocyanins in Dioscorea trifida L. yam tubers (Purple sachapapa). European Food Research and Technology, 230(5), 745-752. http://dx.doi.org/10.1007/s00217-010-1219-5.
http://dx.doi.org/10.1007/s00217-010-121...
; Pérez et al., 2011Pérez, E., Gibert, O., Rolland-Sabaté, A., Jiménez, Y., Sánchez, T., Giraldo, A., Pontoire, B., Guilois, S., Lahon, M. C., Reynes, M., & Dufour, D. (2011). Physicochemical, functional and macromolecular properties of waxy yam starches discovered from“Mapuey” (Dioscorea trifida) genotypes in the Venezuelan Amazon. Journal of Agricultural and Food Chemistry, 59(1), 263-273. http://dx.doi.org/10.1021/jf100418r. PMid:21158430.
http://dx.doi.org/10.1021/jf100418r...
). Therefore, it has attracted the attention of researchers and the food industry as a potential source of ingredients for various foods such as bread, cookies, creamy soups, cake fillings, among others (Teixeira et al., 2013Teixeira, A. P., Oliveira, I. M. A., Lima, E. S., & Matsuura, T. (2013). The use of purple yam (Dioscorea trifida) as a health-promoting ingredient in bread making. Journal Biological Research, 3(1), 747-758. Retrieved from http://www.jresearchbiology.com document/ RA0306
http://www.jresearchbiology.com ...
; Techeira et al., 2014Techeira, N., Sívoli, L., Perdomo, B., Ramírez, A., & Sosa, F. (2014). Caracterización fisico química, funcional y nutricional de harinas crudas obtenidas a partir de diferentes variedades de yuca (Manihot esculenta Crantz), batata (Ipomoea batatas Lam) y ñame (Dioscorea alata), cultivadas en Venezuela. Interciencia, 39(3), 191-197. Retrieved from https://search.proquest.com/docview/1517930100?accountid=199028
https://search.proquest.com/docview/1517...
). However, Dioscorea trifida is perishable and has a limited shelf life after harvesting. Although the dehydration process can be used to produce value-added products and to extend the shelf life and increase year-round marketing of the products, the conventional drying methods often use high temperatures that can degrade heat-sensitive bioactive compounds. Several studies have reported the Refractance Window (RW) technique for juice concentration, fruit and vegetable dehydration, and even yogurt powder production (Raghavi et al., 2018Raghavi, L. M., Moses, J. A., & Anandharamakrishnan, C. (2018). Refractance window drying of foods: a review. Journal of Food Engineering, 222, 267-275. http://dx.doi.org/10.1016/j.jfoodeng.2017.11.032.
http://dx.doi.org/10.1016/j.jfoodeng.201...
; Tontul et al., 2018Tontul, İ., Kasimoglu, Z., Asik, S., Atbakan, T., & Topuz, A. (2018). Functional properties of chickpea protein isolates dried by refractance window drying. International Journal of Biological Macromolecules, 109, 1253-1259. http://dx.doi.org/10.1016/j.ijbiomac.2017.11.135. PMid:29175165.
http://dx.doi.org/10.1016/j.ijbiomac.201...
). In the RW drying system, the material to be dried is placed on polyester film which is partially transparent to infrared radiation and this film will be in contact with the surface of hot water, circulating through the reservoir. The thermal energy of hot water is efficiently transferred through the polyester film to wet food material by means of conduction and radiation (infrared), which, in turn, results in higher rate of mass transfer. This process facilitates drying of food material in shorter time with minimal changes in product quality, such as nutrient content and color, as compared to conventional drying methods (Abonyi et al., 2002Abonyi, B. I., Feng, H., Tang, J., Edwards, C. G., Chew, B. P., Mattinson, D. S., & Fellman, J. K. (2002). Quality retention in strawberry and carrot purees dried with Refractance Window system. Journal of Food Science, 67(3), 1051-1056. http://dx.doi.org/10.1111/j.1365-2621.2002.tb09452.x.
http://dx.doi.org/10.1111/j.1365-2621.20...
; Raghavi et al., 2018Raghavi, L. M., Moses, J. A., & Anandharamakrishnan, C. (2018). Refractance window drying of foods: a review. Journal of Food Engineering, 222, 267-275. http://dx.doi.org/10.1016/j.jfoodeng.2017.11.032.
http://dx.doi.org/10.1016/j.jfoodeng.201...
; Durigon et al., 2018Durigon, A., Parisotto, E. I. B., Carciofi, B. A. M., & Laurindo, J. B. (2018). Heat transfer and drying kinetics of tomato pulp processed by cast-tape drying. Drying Technology, 36(2), 160-168. http://dx.doi.org/10.1080/07373937.2017.1304411.
http://dx.doi.org/10.1080/07373937.2017....
).

Optimal control of the drying process is fundamental and requires complete information on the drying behavior of the materials, requiring an accurate model capable of predicting water removal rates and describing the drying performance of each product under certain conditions (Khatchatourian et al., 2013Khatchatourian, O. A., Vielmo, H. A., & Bortolaia, L. A. (2013). Modelling and simulation of cross flow grain dryers. Biosystems Engineering, 116(4), 335-345. http://dx.doi.org/10.1016/j.biosystemseng.2013.09.001.
http://dx.doi.org/10.1016/j.biosystemsen...
). Mathematical models are an effective tool in the development, design, and improvement of drying systems and analysis of mass transfer phenomena during the drying process (Silva et al., 2014Silva, W. P., Silva, C. M., & Gama, F. J. (2014). Estimation of thermo-physical properties of products with cylindrical shape during drying: The coupling between mass and heat. Journal of Food Engineering, 141, 65-73. http://dx.doi.org/10.1016/j.jfoodeng.2014.05.010.
http://dx.doi.org/10.1016/j.jfoodeng.201...
; Morais & Gut, 2015Morais, A. O., & Gut, J. A. W. (2015). Determination of the effective radial thermal diffusivity for evaluating enhanced heat transfer in tubes under non-Newtonian laminar flow. Brazilian Journal of Chemical Engineering, 32(2), 445-454. http://dx.doi.org/10.1590/0104-6632.20150322s00003318.
http://dx.doi.org/10.1590/0104-6632.2015...
; Zarein et al., 2015Zarein, M., Samadi, S. H., & Ghobadian, B. (2015). Investigation of microwave dryer effect on energy efficiency during drying of apple slices. Journal of the Saudi Society of Agricultural Sciences, 14(1), 41-47. http://dx.doi.org/10.1016/j.jssas.2013.06.002.
http://dx.doi.org/10.1016/j.jssas.2013.0...
; Qiu et al., 2018Qiu, J., Vuist, J. E., Boom, R. M., & Schutyser, M. A. (2018). Formation and degradation kinetics of organic acids during heating and drying of concentrated tomato juice. Lebensmittel-Wissenschaft + Technologie, 87, 112-121. http://dx.doi.org/10.1016/j.lwt.2017.08.081.
http://dx.doi.org/10.1016/j.lwt.2017.08....
). Dincer & Dost (1995)Dincer, I., & Dost, S. A. (1995). An analytical model for diffusing moisture in solid objects during drying. Drying Technology, 13(1-2), 425-435. http://dx.doi.org/10.1080/07373939508916962.
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developed analytical models to characterize the mass transfer during drying of objects presenting regular geometry (plate, cylinder, and sphere) and based on the assumption that the effective moisture diffusivity during drying process remains constant. This model is more simplified when compared to the diffusion model based on Fick's second law, and allows the determination of important parameters for the design, simulation, and optimization of the drying process.

However, to the best of our knowledge, there are no studies on mass transfer parameters and thermodynamic properties of the dehydrated tuber by Refractance Window (RW) technique in the literature. Therefore, this study aimed to evaluate the applicability of the analytical model developed by Dincer & Dost (1995)Dincer, I., & Dost, S. A. (1995). An analytical model for diffusing moisture in solid objects during drying. Drying Technology, 13(1-2), 425-435. http://dx.doi.org/10.1080/07373939508916962.
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using the experimental data of Dioscorea trifida paste subjected to RW drying, and to determine the mass transfer parameters and thermodynamic properties involved in the drying process.

2 Materials and methods

2.1 Plant material and sample preparation

Dioscorea trifida (DT) tubers were purchased from the local market in Belém do Pará (Brazil) and transported to the laboratory. DT tubers were sanitized with a chlorinated solution at 200 mgL-1. The bark (pericarp) was separated manually from the mesocarp using a knife. The mesocarp was washed, cut into approximately 1x1 cm pieces, and homogenized in a food processor (WALITA, RI 3148 SP, Brazil) until a homogeneous paste was obtained. The resulting paste was stored at -5 oC until used for further analysis.

2.2 Refractance Window drying

A batch scale laboratory-operated dryer was constructed using the same principle described by Costa et al. (2019)Costa, R. D. S., Rodrigues, A. M. C., Laurindo, J. B., & Silva, L. H. M. (2019). Development of dehydrated products from peach palm–tucupi blends with edible film characteristics using refractive window. Journal of Food Science and Technology, 56(2), 560-570. http://dx.doi.org/10.1007/s13197-018-3454-x. PMid:30906013.
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, with some modifications (Figure 1). The drier consisted of a metal container (0.9 m x 0.15 m x 0.10 m) with circulation of hot water from a thermostatic bath (Quimis, Q214M2, Brazil), a digital PID temperature controller (Minipa, MT 1044, Brazil) and a 0.20 mm thick mylar film (type D, DuPont, USA). The mylar film was attached to the top of the metallic container. The drying temperatures were 70, 80, and 90 °C. The paste of DT was warmed at room temperature for 2 hours to reach the same equilibrium temperature before drying experiments. For drying the DT sample, 200 g of purple yam paste was spread over the surface of the mylar film forming a flat plate with a 50 mm side and 3.0 mm thickness. Both the initial moisture and the equilibrium moisture were determined according to the AOAC methodology No. 934.06 (Association of Official Analytical Chemists, 1990Association of Official Analytical Chemists – AOAC. (1990). Official methods of analysis (Vol. 2, 15th ed). Arlington: AOAC.) using a vacuum oven (Marconi, MA030, Brazil) and an analytical balance (Shimadzu AY220, Japan) with an accuracy of ± 0.0001 g. The equilibrium moisture reached, as well as the time required to reach it, were specific to each drying regime studied (70, 80 and 90 oC). Each treatment was realized in triplicate.

Figure 1
Schematic diagram of a batch-type RW drying system.

2.3 Data analysis

In this study to explain the moisture transfer mechanism into the sample and at its surface during drying, the following hypothesis was considered: that the moisture transfer during drying is controlled by the diffusion mechanism. In this mechanism water moves from a region with high concentration toward a region at low concentration assuming that the moisture gradient inside biomaterial is the only driving force of the motion. Under this approach the following conditions have been assumed: (i) constant thermophysical properties of the solid and the drying medium; (ii) the effect of heat transfer on the moisture loss is negligible; (iii) The moisture diffusion in one-direction (perpendicular to the slab surface); (iv) and finite internal and external resistances to the moisture transfer within the solids (referring to 0.1<Bim<100). Hence, the transient moisture diffusivity equation in Cartesian coordinates and dimensionless can be written in the following form (Akpinar & Dincer, 2005Akpinar, E. K., & Dincer, I. (2005). Moisture transfer models for slabs drying. International Chemical at Heat Mass Transfer, 32(1-2), 80-93. http://dx.doi.org/10.1016/j.icheatmasstransfer.2004.04.037.
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) (Equations 1 and 2):

φ t = D y φ y (1)
φ = W W e (2)

where ϕ is moisture content difference (kg kg-1 d.b), Dm is moisture diffusivity (m2 s-1), t is time (s) and y is space coordinate.

Equation 1 is subject to the following initial and boundary conditions (Equations 3, 4 and 5):

φ ( y ,0 ) = φ i = ( W i W e ) = Cte . (3)
φ y 0, t = 0 (4)
D m φ L ( L , t ) = k m [ φ ( L , t ) φ o ] (5)

where y = L is thickness (m) and km is moisture transfer coefficient, m.s-1

The dimensionless moisture (Ф) content can be represented in terms of moisture content at any point of the solid object as (Equation 6):

Φ = W W e W i W e (6)

Solution to the governing equation (i.e., Equation 1) under the corresponding boundary conditions gives dimensionless moisture distribution at any point for the slab object is given as following form (Equation 7)(for details see Dincer & Dost, 1995Dincer, I., & Dost, S. A. (1995). An analytical model for diffusing moisture in solid objects during drying. Drying Technology, 13(1-2), 425-435. http://dx.doi.org/10.1080/07373939508916962.
http://dx.doi.org/10.1080/07373939508916...
; Dincer & Dost, 1996Dincer, I., & Dost, S. A. (1996). Modeling study for moisture diffusivities and moisture transfer coefficients in drying of solid objects. International Journal of Energy Research, 20(6), 531-539. http://dx.doi.org/10.1002/(SICI)1099-114X(199606)20:6<531::AID-ER171>3.0.CO;2-6.
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):

Φ = n = 1 A n B n (7)

The solution can be simplified when Fo> 0.2 values are negligibly small. Thus, the infinite sum in Equation 7 is well approximated by the first term only, i.e (Equations 8, 9 and 10) (Dincer & Dost, 1995Dincer, I., & Dost, S. A. (1995). An analytical model for diffusing moisture in solid objects during drying. Drying Technology, 13(1-2), 425-435. http://dx.doi.org/10.1080/07373939508916962.
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):

Φ = ˜ A 1 B 1 (8)

where for slab geometry:

A 1 = exp [ 0.2533 B i / ( 1.3 + B i ) ] (9)
B 1 = exp ( μ 1 2 F o ) (10)

Considering that drying has an exponentially decreasing trend, as proposed by Dincer & Dost (1996)Dincer, I., & Dost, S. A. (1996). Modeling study for moisture diffusivities and moisture transfer coefficients in drying of solid objects. International Journal of Energy Research, 20(6), 531-539. http://dx.doi.org/10.1002/(SICI)1099-114X(199606)20:6<531::AID-ER171>3.0.CO;2-6.
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, the equation for the objects subject to drying, by introducing lag factor (G, dimensionless) and drying coefficient (S, 1 s-1) is (Equation 11):

Φ = G exp ( S t ) (11)

The drying coefficient shows the drying capability of an object or product per unit time and the lag factor is an indication of the internal resistance of an object to the heat and/or moisture transfer during drying. These parameters are useful to evaluate and represent a drying process. The value of the dimensionless moisture content can be obtained using the experimental moisture content measurements from Equation 6.

Both Equations 8 and 11 are in the same form and can be equated to each other by having G = A1. Therefore, the moisture diffusivity for an infinite slab is given by the following Equation 12:

D m = S L 2 μ 1 2 (12)

where μ1 is the first root of the transcendental characteristic equation (Equation 7) and can be calculated with respect to Biot number (Bi) for slab geometry by using the following simplified expression (Equation 13) (Dincer & Hussain, 2002Dincer, I. & Hussain, M. M. (2002). Development of a new Bi–Di correlation for solids drying. International Journal of Heat and Mass Transfer, 45(15), 3065-3069.):

μ 1 = a tan ( 0.640443 B i + 0.380397 ) (13)

The moisture transfer coefficients (km) can be obtained in terms of the lag factor used the Biot number (Bi) which is defined as (Equation 14):

B i = k m L D m (14)

To determine the mass transfer parameters based on the Dincer and Dost model, the following procedure was applied:

  1. i

    Using the least square curve-fitting method, the dimensionless moisture content values and drying time were regressed in the form of Equation 11 and the lag factor (G) and drying coefficient (S) were determined;

  2. ii

    The Biot number was calculated through Equation 9;

  3. iii

    The value of μ1 was determined from Equation 13;

  4. iv

    The moisture diffusivity was calculated using Equation 12;

  5. v

    The moisture transfer coefficient was obtained from Equation 14.

The dependence of Deff on temperature can be determined by a simple Arrhenius expression (Equation 15):

D m = D o exp E a T a b s R (15)

where Ea is the activation energy (kJ mol-1), D0 is the diffusivity value for infinite moisture content, R represents the universal gas constant, and Tabs is the absolute temperature. By plotting ln (Dm) vs. 1/Tabs diagram, Ea and D0 coefficients can be subsequently related to drying air conditions through non-linear regression analysis.

The thermodynamic properties of the mass transfer process in Dioscorea trifida paste subjected to drying by RW was determined according to the method proposed by Jideani & Mpotokwana (2009)Jideani, V. A., & Mpotokwana, S. M. (2009). Modeling of water absorption of botswana bambara varieties using Peleg’s equation. Journal of Food Engineering, 92(2), 182-188. http://dx.doi.org/10.1016/j.jfoodeng.2008.10.040.
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(Equations 16, 17 and 18):

Δ H = E a R T a b s (16)
Δ S = R ln D o ln k B h P ln T a b s (17)
Δ G = Δ H Δ S . T a b s (18)

where ΔH is the differential enthalpy, kJ mol−1; ΔS is the differential entropy, kJ.mol−1.K−1; ΔG is the Gibbs free energy, kJ mol−1; kB is Boltzmann’s constant, 1.38 × 10–23J K−1; and hP is Planck’s constant, 6.626 ×10–34J s-1..

Statistical analysis

All analyses were performed in triplicate (n = 3). The significance of the results was analyzed by a one-way analysis of variance (ANOVA). The parameters of the analytical model proposed by Dincer and Dost (Equation 11), Arrhenius equation (Equation 15) were estimated using the software Statistica for Windows 7.0 (StatSoft Inc., Tulsa, OK, USA). The fit quality of the proposed models for the drying kinetics data was estimated using the correlation coefficient (R2) and the Chi-squared parameter (χ2).

3 Results and discussion

The moisture content of fresh Dioscorea trifida tuber was 77.7 ± 0.1 g 100g-1, and the moisture content of the dried Dioscorea trifida subjected to three different temperatures (70, 80, and 90 oC) ranged from 4.75 to 3.72 g 100 g-1 (on a wet basis). Figure 2 shows the behavior of the dimensionless moisture content of the sample with the drying time for three different temperatures, as well as the estimated values for the RW drying by the model proposed by Dincer and Dost (Equation 10). The behavior of the replicates for the RW-dried purple face sample showed an average difference between the values of dimensionless moisture, to the majority of the date, lower than the error of the dimensionless moisture measurement, proving the reproducibility of the drying experiments in the prototype assembled for this study, observed for all temperatures studied (Figure 2).

Figure 2
Experimental and predicted average dimensionless moisture content of Dioscorea trifida.

A similar trend was observed for the moisture content of the samples at different drying temperatures, with an exponential decrease with drying time, which was accentuated in the initial 10 minutes of drying and decreased slowly during the process. Therefore, at the end of drying, a lower effect of temperature on drying kinetics was observed, when compared to the beginning of the process, and the moisture transport was controlled by internal factors, i.e. the nature of the material.

Table 1 shows the parameters G and S, estimated by the nonlinear adjustment of the Dincer and Dost model (Equation 11) to the experimental data of the drying kinetics of Dioscorea trifida yam subjected to RW drying, the coefficients of determination (R2) and the chi-square values (χ2). It can be noted that S value increased and G value decreased with increasing temperature. The one-way ANOVA showed a significant and positive effect (p <0.05) of temperature on G and S parameters. Similar behavior was also observed by Mrkic et al. (2007)Mrkic, V., Ukrainczyk, M., & Tripalo, B. (2007). Applicability of moisture transfer Bi–Di correlation for convective drying of broccoli. Journal of Food Engineering, 79(2), 640-646. http://dx.doi.org/10.1016/j.jfoodeng.2006.01.078.
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in the convective drying of broccoli using the same geometry, and by Corzo et al. (2008)Corzo, O., Bracho, N., Alvarez, C., Rivas, V., & Rojas, Y. (2008). Determining the moisture transfer parameters during the air drying of mango slices using Biot–Dincer numbers correlation. Journal of Food Process Engineering, 31(6), 853-873. http://dx.doi.org/10.1111/j.1745-4530.2007.00194.x.
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in the convective drying of mango slices at different ripening stages.

Table 1
Drying coefficient and lag factor values obtained for RW drying of Dioscorea trifida paste.

Regarding the application of the Dincer and Dost model (Equation 11), the high coefficients of determination (R2> 0.96) and the low chi-square values (χ2 < 4.06 × 10-3) indicate the adequacy of the model to the experimental data (Table 1).

Concerning the Biot number (Bim), which represents the relationship between internal resistance and external resistance to mass transfer (when 0.1 <Bim <100) (Bezerra et al., 2015Bezerra, C. V., Meller da Silva, L. H., Corrêa, D. F., & Rodrigues, A. M. C. (2015). A modeling study for moisture diffusivities and moisture transfer coefficients in drying of passion fruit peel. International Journal of Heat and Mass Transfer, 85, 750-755. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.02.027.
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), as shown in Table 1, the Bim values ranged from 0.197 to 0.397 for the RW drying, which indicates the presence of internal and external resistance to moisture transfer Similar behavior was also observed by Rajoriya et al. (2019)Rajoriya, D., Shewale, S. R., & Hebbar, H. U. (2019). Refractance window drying of apple slices: mass transfer phenomena and quality parameters. Food and Bioprocess Technology, 12(10), 1646-1658. http://dx.doi.org/10.1007/s11947-019-02334-7.
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in the convective drying of apple slices, with Bim values ranging from 0.128 to 0.594. The one-way ANOVA also showed a significant and positive effect (p <0.05) of the temperature on Bim values, as expected, thus the temperature increase favored the decrease of the internal resistance, leading to a faster drying process. From a technological point of view, this behavior is an advantage of the RW drying method for the final product quality as it allows good retention of thermo sensitive bioactive compounds.

Using the values of Y, S, and μ1, the moisture diffusivity (Dm) was then computed from Equation 12. Subsequently, the moisture transfer coefficient (km) values were computed by Equation 14. The calculated diffusivity (Dm) and moisture transfer coefficient (km) are presented in Table 1. According to the data, the Dm value increased with the increase in temperature from 70 to 90 °C for Dioscorea trifida yam subjected to RW drying. This phenomenon is associated with the lower viscosity of water with an increase in temperature. Whereas viscosity is a measure of fluid resistance to flow, the drying conditions have caused an increase in water diffusion in the yam pulp, thus favoring drying (Wang et al., 2014Wang, C., Liu, S., Wu, J., & Li, Z. (2014). Effects of temperature-dependent viscosity on fluid flow and heat transfer in a helical rectangular duct with a finite pitch. Brazilian Journal of Chemical Engineering, 31(3), 787-797. http://dx.doi.org/10.1590/0104-6632.20140313s00002676.
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). In addition, the higher effective diffusion coefficient may be due to rising temperatures can lead to an increase in the molecular vibration of water, which also contributed to a faster diffusion.

The magnitude of Dm (Table 1) is similar to those reported by several authors for different biological products using different methods of estimation, such as reported by Falade et al. (2007)Falade, K. O., Olurin, T. O., Ike, E. A., & Aworh, O. C. (2007). Effect of pretreatment and temperature on air-drying of Dioscorea alata and Dioscorea rotundata slices. Journal of Food Engineering, 80(4), 1002-1010. http://dx.doi.org/10.1016/j.jfoodeng.2006.06.034.
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found diffusivity values in the range of 0.829 x 10-6-1.12 ×10-5 m2 s-1 for convective drying of Yam (Dioscorea alata) between 50 and 80 °C and at constant air velocity (1.5 m s-1); Mrkic et al. (2007)Mrkic, V., Ukrainczyk, M., & Tripalo, B. (2007). Applicability of moisture transfer Bi–Di correlation for convective drying of broccoli. Journal of Food Engineering, 79(2), 640-646. http://dx.doi.org/10.1016/j.jfoodeng.2006.01.078.
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found diffusivities in the range of 3.58 x 10-6-1.07 × 10-5 m2s-1 for broccoli slices dried at 60 and 80 °C with a constant air velocity of 2.0 m/s, performed in convective dryer; Furtado et al. (2010)Furtado, G. F., Silva, F. S., Porto, A. G., & Santos, P. (2010). Drying of ceriguela pulp through the foam-mat drying method. Revista Brasileira de Produtos Agroindustriais, 12(1), 9-14. Retrieved from http://www.deag.ufcg.edu.br/rbpa/rev1
http://www.deag.ufcg.edu.br/rbpa/rev1...
reported Dm values from 1.99 ×10-7 to 4.56 ×10-7 m2 s-1during drying of seriguela pulp using the foam-mat method at 70-80 °C; Guiné et al. (2011)Guiné, R. P. F., Pinho, S., & Barroca, M. J. (2011). Study of the convective drying of pumpkin (Cucurbita maxima). Food and Bioproducts Processing, 89(4), 422-428. http://dx.doi.org/10.1016/j.fbp.2010.09.001.
http://dx.doi.org/10.1016/j.fbp.2010.09....
found diffusivity values in the range of 4.08 × 10-8 to 2.35 × 10-7 m2 s-1 for convective drying of pumpkin in the temperature range of 30 °C-70 °C; Aforabi et al. (2014)Aforabi, T., Tunde-Akintunde, T., & Olanipekun, B. F. (2014). Effect of drying conditions on energy utilization during cocoyam drying. Agricultural Engineering International: CIGR Journal, 16(4), 135-145 found diffusivities in the range of 5.27 × 10-8-2.07 × 10-6 m2 s-1 in drying of cocoyam slices in the temperature range of 50-70 °C for microwave drying; Bezerra et al. (2015)Bezerra, C. V., Meller da Silva, L. H., Corrêa, D. F., & Rodrigues, A. M. C. (2015). A modeling study for moisture diffusivities and moisture transfer coefficients in drying of passion fruit peel. International Journal of Heat and Mass Transfer, 85, 750-755. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.02.027.
http://dx.doi.org/10.1016/j.ijheatmasstr...
found Dm in the range of 1.05 × 10-8-6.32 × 10-7 m2 s-1 in the drying of passion fruit peel in the temperature range of 50-70 °C. One-way ANOVA revealed a significant positive effect (p < 0.05) of the temperature on moisture diffusivity.

The coefficient km calculated by the Equation 14 ranged from 3.46 ×10-4 to 4.04 × 10-4 m s-1. The results of km found in this study corroborate the findings in the literature for different foods and drying conditions, such as reported by McMinn et al. (2003)McMinn, W. A. M., Khraisheh, M. A. M., & Magee, T. R. A. (2003). Modelling the mass transfer during convective, microwave and combined microwave-convective drying of solid slabs and cylinders. Food Research International, 36(9-10), 977-983. http://dx.doi.org/10.1016/S0963-9969(03)00118-2.
http://dx.doi.org/10.1016/S0963-9969(03)...
studied potato slabs subjected to convective, microwave, and combined microwave–convective drying in the temperature range of 50-70 °C, found km in the range of 0.5 x 10-2 to 0.328 × 10-4 m s-1. Mrkic et al. (2007)Mrkic, V., Ukrainczyk, M., & Tripalo, B. (2007). Applicability of moisture transfer Bi–Di correlation for convective drying of broccoli. Journal of Food Engineering, 79(2), 640-646. http://dx.doi.org/10.1016/j.jfoodeng.2006.01.078.
http://dx.doi.org/10.1016/j.jfoodeng.200...
found km in the range of 1.921 × 10-4-8.725 × 10-4 m s-1 for broccoli slices dried in the temperature range of 60-80 °C. Lemus-Mondaca et al. (2013)Lemus-Mondaca, R. A., Zambra, C. E., Vega-Gálvez, A., & Moraga, N. O. (2013). Coupled 3D heat and mass transfer model for numerical analysis of drying processing papaya slices. Journal of Food Engineering, 116(1), 109-117. http://dx.doi.org/10.1016/j.jfoodeng.2012.10.050.
http://dx.doi.org/10.1016/j.jfoodeng.201...
found km values ranging from 3.10 × 10-7 to 6.05 × 10-6 m s-1 in drying of papaya slices at temperatures between 40 and 80 °C. Bezerra et al. (2015)Bezerra, C. V., Meller da Silva, L. H., Corrêa, D. F., & Rodrigues, A. M. C. (2015). A modeling study for moisture diffusivities and moisture transfer coefficients in drying of passion fruit peel. International Journal of Heat and Mass Transfer, 85, 750-755. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.02.027.
http://dx.doi.org/10.1016/j.ijheatmasstr...
found km in the range of 4.53 × 10-7 to 6.062 × 10-7m s-1 for drying of passion fruit peel in the temperature range of 40 at 60 °C. Arranz et al. (2017)Arranz, F. J., Jimenez-Ariza, T., Diezma, B., & Correa, E. C. (2017). Determination of diffusion and convective transfer coefficients in food drying revisited: A new methodological approach. Biosystems Engineering, 162, 30-39. http://dx.doi.org/10.1016/j.biosystemseng.2017.07.005.
http://dx.doi.org/10.1016/j.biosystemsen...
during carrot drying at temperatures ranging from 40 to 70 °C, and km values in the range of 1.20 ×10-6 to 6.54 × 10-7 m s-1. The influence of temperature on moisture transfer coefficient was positive and significant (p < 0.05) for the temperature ranging between 70 and 90 oC. There are few studies on the determination of km of yam in the literature, despite their importance for the evaluation of mass transfer or simultaneous heat and mass transfer processes.

Activation energy (Ea) was estimated using Equation 15. The Ea was calculated by plotting ln (Dm) vs the reciprocal of the absolute temperature (1/Tabs) as presented Figure 3. The results of such fitting gave a regression coefficient of 0.9985 indicating that the quality of such a fitting was good. The value obtained for the Ea in this study was 44.091 kJ/mol and presents reasonable agreement with the data reported by several authors for foods materials. As reported by Xiao et al. (2013)Xiao, H. W., Yao, X. D., Lin, H., Yang, W. X., Meng, J. S., & Gao, Z. J. (2013). Effect of SSB (superheated steam blanching) time and drying temperature on hot air impingement drying kinetics and quality attributes of yam slices. Journal of Food Process Engineering, 35(3), 370-390. http://dx.doi.org/10.1111/j.1745-4530.2010.00594.x.
http://dx.doi.org/10.1111/j.1745-4530.20...
, the activation energy for a typical drying operation should range from 12.7 to 110 kJ mol-1. Falade et al. (2007)Falade, K. O., Olurin, T. O., Ike, E. A., & Aworh, O. C. (2007). Effect of pretreatment and temperature on air-drying of Dioscorea alata and Dioscorea rotundata slices. Journal of Food Engineering, 80(4), 1002-1010. http://dx.doi.org/10.1016/j.jfoodeng.2006.06.034.
http://dx.doi.org/10.1016/j.jfoodeng.200...
reported the activation energy ranging from 41.75 to 72.47 kJ mol-1 for the convective drying of Dioscorea alata and Dioscorea rotundata slices. Ju et al. (2016)Ju, H.-Y., Law, C.-L., Fang, X.-M., Xiao, H.-W., Liu, Y.-H., & Gao, Z.-J. (2016). Drying kinetics and evolution of the sample’s core temperature and moisture distribution of yam slices (Dioscorea alata L.) during convective hot-air drying. Drying Technology, 34(11), 1297-1306. http://dx.doi.org/10.1080/07373937.2015.1105814.
http://dx.doi.org/10.1080/07373937.2015....
reported activation energy of 29.53 kJ mol-1 for drying of Dioscorea alata, while Srikanth et al. (2019)Srikanth, K. S., Sharanagat, V. S., Kumar, Y., Bhadra, R., Singh, L., Nema, P. K., & Kumar, V. (2019). Convective drying and quality attributes of elephant foot yam (Amorphophalluspaeonii folius). Lebensmittel-Wissenschaft + Technologie, 99, 8-16. http://dx.doi.org/10.1016/j.lwt.2018.09.049.
http://dx.doi.org/10.1016/j.lwt.2018.09....
found values from 25.18 to 32.46 kJ mol-1 during drying of Amorphophallus paeonii folius cubes. Several factors can affect the activation energy, including the variety, ripening stage, sample size, operating conditions, components, and tissue structure of Dioscorea trifida.

Figure 3
Relationship between moisture diffusivity (Dm) and temperature on purple yam dried by refractance window.

Thus, the effect of temperature on the Dm for RW drying of Dioscorea trifida paste can be represented by the following Equation 19:

D m = 13.763 exp 5303.26 T a b s (19)

The thermodynamic properties observed for RW drying of Dioscorea trifida paste subjected to different temperatures are presented in Table 1. The enthalpy values (ΔH) were positive, pointing to endergonic reactions, that is, heat energy was necessary for the process. However, a reduction in energy demand from 41.238 to 41.071 kJ mol-1 was observed with an increase in drying temperature, which corroborates other studies on drying of other agricultural products (Beigi, 2016Beigi, M. (2016). Influence of drying air parameters on mass transfer characteristics of apple slices. International Journal of Heat and Mass Transfer, 52(10), 2213-2221. http://dx.doi.org/10.1007/s00231-015-1735-8.
http://dx.doi.org/10.1007/s00231-015-173...
; Costa et al., 2016Costa, C. F., Corrêa, P. C., Vanegas, J. D., Baptestini, F. M., Campos, R. C., & Fernandes, L. S. (2016). Mathematical modeling and determination of thermodynamic properties of jabuticaba peel during the drying process. Revista Brasileira de Engenharia Agrícola e Ambiental, 20(6), 576-580. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n6p576-580.
http://dx.doi.org/10.1590/1807-1929/agri...
; Fayose & Huan, 2016Fayose, F., & Huan, Z. (2016). Heat pump drying of fruits and vegetables: principles and potentials for Sub-Saharan Africa. International Journal of Food Science, 2016, 9673029. http://dx.doi.org/10.1155/2016/9673029. PMid:26904668.
http://dx.doi.org/10.1155/2016/9673029...
; Chayjan et al., 2011Chayjan, R. A., Peyman, M. H., Esna-Ashari, M., & Salari, K. (2011). Influence of drying conditions on diffusivity, energy and color of seedless grape after dipping process. Australian Journal of Crop Science, 5, 96-103. Retrieved from http://www.cropj.com/chayjan512011
http://www.cropj.com/chayjan512011...
).

All entropy values (ΔS) (Table 1) for RW drying of the Dioscorea trifida paste was negative (ΔS <0), indicating no significant increase in the system disorder. The ΔS values decreased with temperature increments, probably due to the decrease in moisture and restricted movement of water molecules, as there are few sites available during the dehydration process. This behavior can also be due to the formation of an activated complex when a substance can present negative entropy when the degree of freedom of translation or rotation is lost during the process.

In contrast to ΔH and ΔS, the Gibbs free energy (ΔG) increased with the increase in temperature, ranging from 118.207 at 122.671 kJ mol-1 for the temperature range studied. Positive ΔG values indicate that RW drying of Dioscorea trifida paste is a non-spontaneous process, once it requires additional energy from the environment around the product to reduce the water content. In this case, hot water was a source of external energy. Similar behavior was previously reported by Rajoriya et al. (2019)Rajoriya, D., Shewale, S. R., & Hebbar, H. U. (2019). Refractance window drying of apple slices: mass transfer phenomena and quality parameters. Food and Bioprocess Technology, 12(10), 1646-1658. http://dx.doi.org/10.1007/s11947-019-02334-7.
http://dx.doi.org/10.1007/s11947-019-023...
.

4 Conclusion

Refractance windows drying is an effective tool in the drying process of tubers such as Dioscorea trifida yam. The drying of Dioscorea trifida paste using RW, can be predict by the model developed by Dincer and Dost with good accuracy and reliability to calculate Dm and Km mass transfer parameters, within the ranges of other agricultural products and with high coefficients of determination and low chi-square values. Unlike other types of drying, it was possible to obtain powdered purple yam, at the three temperatures tested, in times of twenty-five to forty minutes, according to the temperature, in a simple and easy-to-build equipment.

The relationship between Dm and temperature can be described by the Arrhenius equation, which has activation energy of 44.091 kJ mol-1 for the RW drying of Dioscorea trifida paste. In addition, the thermodynamic properties pointed to a non-spontaneous process, with positive ΔH and ΔG values, and negative ΔS values. The ΔH and ΔS values decreased with increasing drying temperature, while ΔG values increased within the temperature range evaluated (70 to 90 °C). These findings can be used for the simulation and optimization of the drying process of Dioscorea trifida yam paste.

Acknowledgements

The authors thank PROPESP/UFPA (Provost’s Office for Research and Graduate Studies of the Federal University of Pará), CNPq (National Research and Development Council, processes, 309876/2016-8, 308396/2018-9 and 313453/2019-5), and CAPES (Coordination for the Improvement of Higher Education Personnel).

  • Practical Application: Use of the Refractance WindowTM technique for the production of dehydrated foods with maintenance of functional properties, with low production cost and application on a small scale.

References

  • Abonyi, B. I., Feng, H., Tang, J., Edwards, C. G., Chew, B. P., Mattinson, D. S., & Fellman, J. K. (2002). Quality retention in strawberry and carrot purees dried with Refractance Window system. Journal of Food Science, 67(3), 1051-1056. http://dx.doi.org/10.1111/j.1365-2621.2002.tb09452.x
    » http://dx.doi.org/10.1111/j.1365-2621.2002.tb09452.x
  • Aforabi, T., Tunde-Akintunde, T., & Olanipekun, B. F. (2014). Effect of drying conditions on energy utilization during cocoyam drying. Agricultural Engineering International: CIGR Journal, 16(4), 135-145
  • Akpinar, E. K., & Dincer, I. (2005). Moisture transfer models for slabs drying. International Chemical at Heat Mass Transfer, 32(1-2), 80-93. http://dx.doi.org/10.1016/j.icheatmasstransfer.2004.04.037
    » http://dx.doi.org/10.1016/j.icheatmasstransfer.2004.04.037
  • Andres, C., Adeoluwa, O., & Bhullar, G. S. (2017). Yam (Dioscorea spp.). In B. Thomas, B. G. Murray & D. J. Murphy (Eds.), Encyclopedia of applied plant sciences (Vol. 3, pp. 435-441). Waltham, M. A.: Academic Press.
  • Arranz, F. J., Jimenez-Ariza, T., Diezma, B., & Correa, E. C. (2017). Determination of diffusion and convective transfer coefficients in food drying revisited: A new methodological approach. Biosystems Engineering, 162, 30-39. http://dx.doi.org/10.1016/j.biosystemseng.2017.07.005
    » http://dx.doi.org/10.1016/j.biosystemseng.2017.07.005
  • Association of Official Analytical Chemists – AOAC. (1990). Official methods of analysis (Vol. 2, 15th ed). Arlington: AOAC.
  • Beigi, M. (2016). Influence of drying air parameters on mass transfer characteristics of apple slices. International Journal of Heat and Mass Transfer, 52(10), 2213-2221. http://dx.doi.org/10.1007/s00231-015-1735-8
    » http://dx.doi.org/10.1007/s00231-015-1735-8
  • Bezerra, C. V., Meller da Silva, L. H., Corrêa, D. F., & Rodrigues, A. M. C. (2015). A modeling study for moisture diffusivities and moisture transfer coefficients in drying of passion fruit peel. International Journal of Heat and Mass Transfer, 85, 750-755. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.02.027
    » http://dx.doi.org/10.1016/j.ijheatmasstransfer.2015.02.027
  • Castro, A. D., Fraxe, T. J., Pereira, H. D. S., & Kinupp, V. F. (2012). Etnobotânica das variedades locais do cará (Dioscorea spp.) cultivados em comunidades no município de Caapiranga, estado do Amazonas. Acta Botanica Brasílica, 26(3), 658-667. http://dx.doi.org/10.1590/S0102-33062012000300015
    » http://dx.doi.org/10.1590/S0102-33062012000300015
  • Chayjan, R. A., Peyman, M. H., Esna-Ashari, M., & Salari, K. (2011). Influence of drying conditions on diffusivity, energy and color of seedless grape after dipping process. Australian Journal of Crop Science, 5, 96-103. Retrieved from http://www.cropj.com/chayjan512011
    » http://www.cropj.com/chayjan512011
  • Corzo, O., Bracho, N., Alvarez, C., Rivas, V., & Rojas, Y. (2008). Determining the moisture transfer parameters during the air drying of mango slices using Biot–Dincer numbers correlation. Journal of Food Process Engineering, 31(6), 853-873. http://dx.doi.org/10.1111/j.1745-4530.2007.00194.x
    » http://dx.doi.org/10.1111/j.1745-4530.2007.00194.x
  • Costa, C. F., Corrêa, P. C., Vanegas, J. D., Baptestini, F. M., Campos, R. C., & Fernandes, L. S. (2016). Mathematical modeling and determination of thermodynamic properties of jabuticaba peel during the drying process. Revista Brasileira de Engenharia Agrícola e Ambiental, 20(6), 576-580. http://dx.doi.org/10.1590/1807-1929/agriambi.v20n6p576-580
    » http://dx.doi.org/10.1590/1807-1929/agriambi.v20n6p576-580
  • Costa, R. D. S., Rodrigues, A. M. C., Laurindo, J. B., & Silva, L. H. M. (2019). Development of dehydrated products from peach palm–tucupi blends with edible film characteristics using refractive window. Journal of Food Science and Technology, 56(2), 560-570. http://dx.doi.org/10.1007/s13197-018-3454-x PMid:30906013.
    » http://dx.doi.org/10.1007/s13197-018-3454-x
  • Dincer, I., & Dost, S. A. (1995). An analytical model for diffusing moisture in solid objects during drying. Drying Technology, 13(1-2), 425-435. http://dx.doi.org/10.1080/07373939508916962
    » http://dx.doi.org/10.1080/07373939508916962
  • Dincer, I., & Dost, S. A. (1996). Modeling study for moisture diffusivities and moisture transfer coefficients in drying of solid objects. International Journal of Energy Research, 20(6), 531-539. http://dx.doi.org/10.1002/(SICI)1099-114X(199606)20:6<531::AID-ER171>3.0.CO;2-6
    » http://dx.doi.org/10.1002/(SICI)1099-114X(199606)20:6<531::AID-ER171>3.0.CO;2-6
  • Dincer, I. & Hussain, M. M. (2002). Development of a new Bi–Di correlation for solids drying. International Journal of Heat and Mass Transfer, 45(15), 3065-3069.
  • Durigon, A., Parisotto, E. I. B., Carciofi, B. A. M., & Laurindo, J. B. (2018). Heat transfer and drying kinetics of tomato pulp processed by cast-tape drying. Drying Technology, 36(2), 160-168. http://dx.doi.org/10.1080/07373937.2017.1304411
    » http://dx.doi.org/10.1080/07373937.2017.1304411
  • Falade, K. O., Olurin, T. O., Ike, E. A., & Aworh, O. C. (2007). Effect of pretreatment and temperature on air-drying of Dioscorea alata and Dioscorea rotundata slices. Journal of Food Engineering, 80(4), 1002-1010. http://dx.doi.org/10.1016/j.jfoodeng.2006.06.034
    » http://dx.doi.org/10.1016/j.jfoodeng.2006.06.034
  • Fayose, F., & Huan, Z. (2016). Heat pump drying of fruits and vegetables: principles and potentials for Sub-Saharan Africa. International Journal of Food Science, 2016, 9673029. http://dx.doi.org/10.1155/2016/9673029 PMid:26904668.
    » http://dx.doi.org/10.1155/2016/9673029
  • Furtado, G. F., Silva, F. S., Porto, A. G., & Santos, P. (2010). Drying of ceriguela pulp through the foam-mat drying method. Revista Brasileira de Produtos Agroindustriais, 12(1), 9-14. Retrieved from http://www.deag.ufcg.edu.br/rbpa/rev1
    » http://www.deag.ufcg.edu.br/rbpa/rev1
  • Guiné, R. P. F., Pinho, S., & Barroca, M. J. (2011). Study of the convective drying of pumpkin (Cucurbita maxima). Food and Bioproducts Processing, 89(4), 422-428. http://dx.doi.org/10.1016/j.fbp.2010.09.001
    » http://dx.doi.org/10.1016/j.fbp.2010.09.001
  • Jideani, V. A., & Mpotokwana, S. M. (2009). Modeling of water absorption of botswana bambara varieties using Peleg’s equation. Journal of Food Engineering, 92(2), 182-188. http://dx.doi.org/10.1016/j.jfoodeng.2008.10.040
    » http://dx.doi.org/10.1016/j.jfoodeng.2008.10.040
  • Ju, H.-Y., Law, C.-L., Fang, X.-M., Xiao, H.-W., Liu, Y.-H., & Gao, Z.-J. (2016). Drying kinetics and evolution of the sample’s core temperature and moisture distribution of yam slices (Dioscorea alata L.) during convective hot-air drying. Drying Technology, 34(11), 1297-1306. http://dx.doi.org/10.1080/07373937.2015.1105814
    » http://dx.doi.org/10.1080/07373937.2015.1105814
  • Khatchatourian, O. A., Vielmo, H. A., & Bortolaia, L. A. (2013). Modelling and simulation of cross flow grain dryers. Biosystems Engineering, 116(4), 335-345. http://dx.doi.org/10.1016/j.biosystemseng.2013.09.001
    » http://dx.doi.org/10.1016/j.biosystemseng.2013.09.001
  • Lemus-Mondaca, R. A., Zambra, C. E., Vega-Gálvez, A., & Moraga, N. O. (2013). Coupled 3D heat and mass transfer model for numerical analysis of drying processing papaya slices. Journal of Food Engineering, 116(1), 109-117. http://dx.doi.org/10.1016/j.jfoodeng.2012.10.050
    » http://dx.doi.org/10.1016/j.jfoodeng.2012.10.050
  • McMinn, W. A. M., Khraisheh, M. A. M., & Magee, T. R. A. (2003). Modelling the mass transfer during convective, microwave and combined microwave-convective drying of solid slabs and cylinders. Food Research International, 36(9-10), 977-983. http://dx.doi.org/10.1016/S0963-9969(03)00118-2
    » http://dx.doi.org/10.1016/S0963-9969(03)00118-2
  • Morais, A. O., & Gut, J. A. W. (2015). Determination of the effective radial thermal diffusivity for evaluating enhanced heat transfer in tubes under non-Newtonian laminar flow. Brazilian Journal of Chemical Engineering, 32(2), 445-454. http://dx.doi.org/10.1590/0104-6632.20150322s00003318
    » http://dx.doi.org/10.1590/0104-6632.20150322s00003318
  • Mrkic, V., Ukrainczyk, M., & Tripalo, B. (2007). Applicability of moisture transfer Bi–Di correlation for convective drying of broccoli. Journal of Food Engineering, 79(2), 640-646. http://dx.doi.org/10.1016/j.jfoodeng.2006.01.078
    » http://dx.doi.org/10.1016/j.jfoodeng.2006.01.078
  • Oliveira, A. P., Barbosa, L. J. N., Pereira, W. E., Silva, J. E. L., & Oliveira, A. N. P. (2007). Produção de túberas comerciais de inhame em função de doses de nitrogênio. Horticultura Brasileira, 25(1), 73-76. http://dx.doi.org/10.1590/S0102-05362007000100014
    » http://dx.doi.org/10.1590/S0102-05362007000100014
  • Pérez, E., Gibert, O., Rolland-Sabaté, A., Jiménez, Y., Sánchez, T., Giraldo, A., Pontoire, B., Guilois, S., Lahon, M. C., Reynes, M., & Dufour, D. (2011). Physicochemical, functional and macromolecular properties of waxy yam starches discovered from“Mapuey” (Dioscorea trifida) genotypes in the Venezuelan Amazon. Journal of Agricultural and Food Chemistry, 59(1), 263-273. http://dx.doi.org/10.1021/jf100418r PMid:21158430.
    » http://dx.doi.org/10.1021/jf100418r
  • Qiu, J., Vuist, J. E., Boom, R. M., & Schutyser, M. A. (2018). Formation and degradation kinetics of organic acids during heating and drying of concentrated tomato juice. Lebensmittel-Wissenschaft + Technologie, 87, 112-121. http://dx.doi.org/10.1016/j.lwt.2017.08.081
    » http://dx.doi.org/10.1016/j.lwt.2017.08.081
  • Raghavi, L. M., Moses, J. A., & Anandharamakrishnan, C. (2018). Refractance window drying of foods: a review. Journal of Food Engineering, 222, 267-275. http://dx.doi.org/10.1016/j.jfoodeng.2017.11.032
    » http://dx.doi.org/10.1016/j.jfoodeng.2017.11.032
  • Rajoriya, D., Shewale, S. R., & Hebbar, H. U. (2019). Refractance window drying of apple slices: mass transfer phenomena and quality parameters. Food and Bioprocess Technology, 12(10), 1646-1658. http://dx.doi.org/10.1007/s11947-019-02334-7
    » http://dx.doi.org/10.1007/s11947-019-02334-7
  • Ramos-Escudero, F., Santos-Buelga, C., Pérez-Alonso, J. J., Yáñez, J. A., & Dueñas, M. (2010). HPLC-DAD-ESI/MS identification of anthocyanins in Dioscorea trifida L. yam tubers (Purple sachapapa). European Food Research and Technology, 230(5), 745-752. http://dx.doi.org/10.1007/s00217-010-1219-5
    » http://dx.doi.org/10.1007/s00217-010-1219-5
  • Silva, W. P., Silva, C. M., & Gama, F. J. (2014). Estimation of thermo-physical properties of products with cylindrical shape during drying: The coupling between mass and heat. Journal of Food Engineering, 141, 65-73. http://dx.doi.org/10.1016/j.jfoodeng.2014.05.010
    » http://dx.doi.org/10.1016/j.jfoodeng.2014.05.010
  • Srikanth, K. S., Sharanagat, V. S., Kumar, Y., Bhadra, R., Singh, L., Nema, P. K., & Kumar, V. (2019). Convective drying and quality attributes of elephant foot yam (Amorphophalluspaeonii folius). Lebensmittel-Wissenschaft + Technologie, 99, 8-16. http://dx.doi.org/10.1016/j.lwt.2018.09.049
    » http://dx.doi.org/10.1016/j.lwt.2018.09.049
  • Techeira, N., Sívoli, L., Perdomo, B., Ramírez, A., & Sosa, F. (2014). Caracterización fisico química, funcional y nutricional de harinas crudas obtenidas a partir de diferentes variedades de yuca (Manihot esculenta Crantz), batata (Ipomoea batatas Lam) y ñame (Dioscorea alata), cultivadas en Venezuela. Interciencia, 39(3), 191-197. Retrieved from https://search.proquest.com/docview/1517930100?accountid=199028
    » https://search.proquest.com/docview/1517930100?accountid=199028
  • Teixeira, A. P., Oliveira, I. M. A., Lima, E. S., & Matsuura, T. (2013). The use of purple yam (Dioscorea trifida) as a health-promoting ingredient in bread making. Journal Biological Research, 3(1), 747-758. Retrieved from http://www.jresearchbiology.com document/ RA0306
    » http://www.jresearchbiology.com
  • Tontul, İ., Kasimoglu, Z., Asik, S., Atbakan, T., & Topuz, A. (2018). Functional properties of chickpea protein isolates dried by refractance window drying. International Journal of Biological Macromolecules, 109, 1253-1259. http://dx.doi.org/10.1016/j.ijbiomac.2017.11.135 PMid:29175165.
    » http://dx.doi.org/10.1016/j.ijbiomac.2017.11.135
  • Wang, C., Liu, S., Wu, J., & Li, Z. (2014). Effects of temperature-dependent viscosity on fluid flow and heat transfer in a helical rectangular duct with a finite pitch. Brazilian Journal of Chemical Engineering, 31(3), 787-797. http://dx.doi.org/10.1590/0104-6632.20140313s00002676
    » http://dx.doi.org/10.1590/0104-6632.20140313s00002676
  • Xiao, H. W., Yao, X. D., Lin, H., Yang, W. X., Meng, J. S., & Gao, Z. J. (2013). Effect of SSB (superheated steam blanching) time and drying temperature on hot air impingement drying kinetics and quality attributes of yam slices. Journal of Food Process Engineering, 35(3), 370-390. http://dx.doi.org/10.1111/j.1745-4530.2010.00594.x
    » http://dx.doi.org/10.1111/j.1745-4530.2010.00594.x
  • Zarein, M., Samadi, S. H., & Ghobadian, B. (2015). Investigation of microwave dryer effect on energy efficiency during drying of apple slices. Journal of the Saudi Society of Agricultural Sciences, 14(1), 41-47. http://dx.doi.org/10.1016/j.jssas.2013.06.002
    » http://dx.doi.org/10.1016/j.jssas.2013.06.002

Publication Dates

  • Publication in this collection
    03 June 2022
  • Date of issue
    2022

History

  • Received
    29 July 2021
  • Accepted
    23 Feb 2022
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