Kinetics of water absorption expansion of rice during soaking at different temperatures and correlation analysis upon the influential factors

Five model equations were used to study the water absorbing expansion kinetics of rice during soaking. The results indicated that the changes of water absorbing expansion in Japonica and Indica rice during soaking at 25, 40, 50, 60 and 70 ℃ can be well simulated (R2 > 0.97) by the five model equations. The linear and polynomial equation could fit the changes of model coefficients and all obtained coefficient parameters could be combined in only one equation to predict the water absorbing characteristics of Japonica and Indica rice. The correlation between the basic nutritional components and model coefficients was further analyzed. The results indicated that the water absorbing rate had significant (P < 0.05) negative correlation with protein content, the apparent amylose content had significant (P < 0.05) negative correlation with the maximum expansion ratio, the length and width of rice affect its water absorbing characteristics.