Modeling water sorption in okara soy milk

Moisture sorption isotherms of okara soy milk were determined using the gra vimetric method in the range 20 - 50 degreesC. The sorption isotherms exhib ited hysteresis along all the wafer activity range (0.1 - 0.9). The amount of sorbed water increased as the temperature was decreased. The GAB and Hal sey models gave a good fit for okara isotherms over the range of water acti vity 0.1 - 0.9. As temperature increased, GAB k-values increased towards un ity where the GAB equation reduces to the BET equation. The influence of te mperature on the constants of GAB and Halsey models was evaluated through A rrhenius-type equations. The Clausius Clapeyron equation was used to estimate the isosteric heats of sorption.