Abstract:According to the process of aqueous enzymatic extraction（AEE），the soluble protein in corn germ was divided into two parts after corn germ soaking in citric acid buffer，hydrothermal treatment （HTT），draining，crushing，and enzymolysis. One part was in the soaking solution，and the other part was in the enzymatic hydrolysate. The soaking solution and the enzymatic hydrolysate were separately concentrated and freeze-dried to prepare the soluble protein. The influences of buffer pH and HTT time on the yield，emulsifying capacity（EC） of the protein and molecular weight distribution （MWD） of the soluble protein in the soaking solution and the enzymatic hydrolysate were studied. The results showed that lower buffer pH within the range of pH3-5 and longer HTT time within the range of 30-90 min were conductive to the yield improvement of protein in the soaking solution and enzymatic hydrolysate. Buffer pH and HTT time had stronger influences on EC of the protein and MWD of the soluble protein in the enzymatic hydrolysate and little influences on EC of the protein and MWD of the soluble protein in the soaking solution. The soluble protein in the soaking solution had lower relative molecular weight than that in the enzymatic hydrolysate，which showed that it had little influence on the yield of free oil.