Moisture Sorption Isotherm Characteristic of Composite Flour (Cassava, Rice, Sorghum, and Sago) at Various Fitting Models

Abstract

Cassava, rice, sorghum, and sago flour can be mixed into composite flour. The properties of composite flour easily absorb water, so it is necessary to know the isotherm sorption through various models, such as Brunauer-Emmet-Teller (BET), Oswin, Hasley, Henderson, Caurie, Chen-Clayton and Guggenheim, Anderson, and Boer (GAB). Information on the sorption properties of foods is of great importance in food dehydration, especially in the quantitative approach to predicting the shelf life of dried foods such as flour. This research aims to determine the sorption isotherms of composite flour experimentally and evaluate the suitability of various mathematical models for fitting the isotherms. Samples were stored at 28 ± 2 ° C with various water activity conditions (aw 0.05-0.97). The results showed that the moisture sorption isotherm of composite flour followed the sigmoid type II behavior frequently found in dry food products. The behavior of composite flour (Formula A and C) equilibrium moisture in the study was satisfactorily described by means of the moisture sorption isotherm of Oswin model with MRD value respectively is 5.64 and 4.93. While the behavior equilibrium moisture for other flour (Formula B and D) was precisely depicted by means of the moisture sorption isotherm of Chen Clayton model with MRD value respectively is 5.08 and 3.39.