Abstract:

The desorption and adsorption isotherms of soybeans were determined at room temperature (25 ℃). Five
commonly used models including Oswin, GAB, Halsey, Hendenson, and Chung-Pfost were applied to fit the experimental
data and to determine the best model as well as its parameters with non-linear regression analysis. The results indicated
that the desorption isotherm of soybeans belonged to type II, but the adsorption isotherm of soybean belonged to type III.
Within the whole scope of water activity, there was a hysteresis loop for soybean desorption-adsorption isotherms. The Oswin model
demonstrated the best fitting model for soybean desorption-adsorption isotherms with coefficient of determination r2 > 0.993. The
parameters A and B of Oswin model for desorption were 0.075 and 0.500, and thosef or adsorption were 0.075 and 0.498, respectively.

Key words: soybean, desorption, adsorption, isotherm, fitting model