Abstract: In this study, the gastric digestibility of dialyzed and non-dialyzed soybean protein was investigated using a static digestion model and a semi-dynamic digestion model. The results from the static model suggested that dialysis had no effect on the gastric digestion process of soy protein. However, in the semi-dynamic model, the pH, dry matter mass of emptied digesta and free amino group content of the non-dialyzed soy protein (SP-ND) differed somewhat from those of the dialyzed soy protein (SP-D) indicating that the SP-ND retained more components in soybeans, resulting in a greater buffering capacity, delayed gastric emptying and slower protein digestion. In addition, the static and semi-dynamic digestion models had different advantages, so they can be used for different research purposes. This work could provide new insights into the development and health effects of soy protein-based products.

Key words: soy protein; dialysis; static digestion model; semi-dynamic digestion model; digestibility