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Modeling of convective drying of cornstarch-alginate gel slabs

Silva Júnior, Marco A.V., Rabi, José A., Ribeiro, Rogers, Dacanal, Gustavo C.
Journal of food engineering 2019 v.250 pp. 9-17
calcium alginate, corn starch, diffusivity, drying, finite element analysis, foods, gels, mass transfer, mathematical models, shrinkage, slabs
This work aimed at developing numerical models to predict the moisture and size of slices of gels containing gelatinized or native cornstarch and calcium alginate, during convective drying. The coupling of mass transfer and shrinkage simulated the drying kinetics with evaluation of effective mass diffusivity. Drying of gels containing 34% wb cornstarch (GC90 and RC90 samples) were well fitted by the analytical solution of Fick's second law, with R2 of 0.963–0.998. The numerical model developed in finite element method via COMSOL Multiphysics better described the drying of gels formulated with 5.4% wb of cornstarch (GC50 and RC50 samples), yielding R2 of 0.958–0.992. Shrinkage was estimated by the molar flux of water and simulated by the Arbitrary Lagrangian-Eulerian (ALE) method. The shrinkage term modified the drying rate profiles and a pseudo-constant rate period was observed. The developed model can be applied in drying studies of gels or foodstuffs with high shrinkage ratio.