ASSESSMENT of A SEMI‐EMPIRICAL FOUR PARAMETER GENERAL MODEL FOR SIGMOID MOISTURE SORPTION ISOTHERMS1

作者：Micha Peleg · 发表于：Journal of Food Process Engineering · 年份：1993 · DOI：10.1111/j.1745-4530.1993.tb00160.x · 被引用次数：383 · 研究领域：Food Drying and Modeling、Adsorption and Cooling Systems、Heat Transfer and Optimization

ABSTRACT Published sigmoid moisture sorption isotherms (0 < aw < ∼ 0.9) were fitted by the four parameter models m = k1awn1+ k2awn2 where m is the moisture contents (dry basis), aw the water activity and the k and n values are constants (n1 < 1 and n2 > 1). Not surprisingly, the model had the same or better fit than the GAB model. In contrast with both the BET and GAB models, the proposed model is not based on the assumption that there exists a well‐defined monolayer of absorbed water. At aw < ∼ 0.4 and n1 > ∼ 0.55, however, the model produces a practically linear aw/[m(1 – aw)] vs aw plot, of the kind used to calculate the monolayer moisture with the BET model. The proposed model can be a convenient means to catalog both sigmoid and nonsigmoid isotherms, and used to calculate the equilibrium water activity of dry mixtures with equations solving software.