Prediction of the melting behavior of edible fats using UNIFAC and UNIQUAC models

Algorithms for solid-liquid equilibrium (SLE) calculations are essential tools for describing physical properties of food systems and for developing formulations of new food products. In this work, SLE was applied to describe the melting behavior of edible fats of relevance to the food industry. The original UNIFAC method and a predictive version of the UNIQUAC model {[}Coutinho, Ind. Eng. Chem. Res., 37 (1998) p. 4870-4875] were used to calculate compounds' activity coefficients for both liquid and solid phases. Equilibrium and mass balance equations were solved using a solid-liquid version of the well-known isoenthalpic flash algorithm and the predictive ability of the method was tested for describing solid fat content (SFC) curves of selected fats. In the case of the UNIQUAC model, global structural parameters were also fitted in order to best represent triacylglycerol (TAG) molecules in the solid phase, allowing a general discussion about the use of experimental data for improving the modeling approach. Reasonable quantitative agreement between predictions and experimental data were achieved revealing the necessity of considering the nonideality of both liquid and solid phases in the subject of oils and fats cristallization. The modeling approach presented here is particularly interesting for developing new fat based product formulations, being a valuable alternative to costly and time consuming experimental approaches. (C) 2019 Elsevier B.V. All rights reserved. (AU)