Abstract: From the kinetics point of view, the mechanism of solubilization of rice dreg protein concentrates (RDPC) was discussed and would include: enzyme interacted with RDPC suspensions partly by rapid adsorption into RDPC particles, increasing solubilization of insoluble proteins, and partly due to protein fragments proteolysis cleaved by the adsorbed enzyme already dissolved in the liquor. The product inhibited the enzyme activity. Experiment of addition of substrate in a batch reaction showed fresh substrate can increased the extent of solubilization and better utilization of the enzyme. It also suggested that the immobilized-enzyme recycle system can decrease the product inhibition of enzyme activity. The initial reaction velocity equation is established as follows: V0=k2X1mK1[E]0[S]0/1+K1[E]0+K1[S]0X1m=0.8859×[E]0[S]0V0/1+6.3027[E]0+0.03590[S]0 Gel filtration of hydrolysate showed that the hydrolysis of insoluble fraction of Pr is possibly fit for“ Zipper Reaction” model.

Key words: rice dreg protein concentrates (RDPC), solubilization, Alcalase