Estimating moisture absorption kinetics of beans during soaking using mathematical models

Abstract

In this paper, fourteen standard models were used to estimate the moisture ratio of three varieties of bean in Iran (Talash, Sadri and Mahali Khomein).  The experiments were carried out using distilled water at three temperatures (5°C, 25°C and 45°C) and three replicates.  The standard models of water absorption were fitted to the experimental data.  To evaluate the models, three parameters: coefficient of determination (R2), chi-square (2) and root mean square error (RMSE) were used.  The appropriate model was chosen based on maximum value of coefficient of determination and minimum value of chi-square and root mean square error.  The effective moisture diffusivity coefficient of three verities in each temperature was estimated by Fick’s equation.  The result demonstrated that the Weibull model is the most appropriate for each variety in three experimental temperatures to estimate moisture ratio changes versus time in soaking.  Thus, moisture ratio versus time was plotted for each case, using Weibull equation.  The plotted curves of each variety of bean indicated that moisture ratio decreases with increase in temperature.  Besides that, the effective moisture diffusivity coefficient of three verities increased in response to increasing temperature from 5 - 45°C.
Keywords: water uptake, hydration, moisture ratio, moisture diffusivity, Weibull model