Freeze drying of turkey breast meat: Mathematical modeling and estimation of transport parameters

Abstract

Freeze drying is an ideal process to produce high-quality dehydrated food products. In this work, a modified mathematical model was constructed and solved in order to describe quantitatively the dynamic behavior of the primary and secondary drying stages of the freeze drying of turkey breast meat in trays. A numerical method of orthogonal collocation based on polynomial approximation was used to obtain solution of mathematical models. Some transport parameters and physical properties that characterize freeze drying of turkey breast meat were determined by fitting experimental data with the mathematical model using the nonlinear least-square method of the Levenberg-Marquardt algorithm of MATLAB. The best-fitted Knudsen diffusivity constant for water vapor, K-w, film thermal conductivity constant, k(f), effective thermal conductivity of the porous dried layer, k(Ie), desorption rate constant of bound water during the secondary drying stage,k(d), and initial value for weight fraction of bound water in dried layer, found to be 3.1151x10(-5)(T-I+T-x)(0.5)m(2)/s, 2.0580x10(-3)P kW/m(2)K, 44.2x10(-6)[1-0.325exp (-5x10(-3) P)] kW/m K, 5.07x10(-5)s(-1) and 0.3276kg water/kg solid, respectively. By using best-fitted parameters in the dynamic mathematical model, the duration of primary and secondary drying stages for 12.4-mm-thick turkey breast meat slabs were found to be 11.0h and 17h, respectively. The mathematical model was validated with 14.5-mm-thick turkey breast slab. There was good agreement between the experimental data and the theoretical results.