Effects of soy protein isolate hydrolysates on cholecystokinin released by rat intestinal mucosal cells and food intake in rats

Soy protein isolate hydrolysates (SPIH) were prepared from soy protein isolate (SPI). Effects of SPIH on a satiety signal cholecystokinin (CCK) and feeding behavior in rats were investigated. SPIH induced more CCK release (164.66 ± 2.40 pg/mL) by rat intestinal mucosal cells than SPI (143.33 ± 3.71 pg/mL). Meal size (MS), intermeal interval (IMI), and satiety ratio (SR = MS/IMI) of rats received different daily doses of SPIH or dietary fiber were detected for 40 days. A 100 mg/kg dose of SPIH resulted in a greater SR than an identical dose of dietary fiber, while a 300 mg/kg dose resulted in a less MS and IMI. A 500 mg/kg dose of SPIH had similar effects to the same dose of dietary fiber on reducing MS, extending IMI, and increasing SR, but resulted in a significantly less body weight at the end of the experiment (318.15 ± 17.83 g) than the dietary fiber group (340.28 ± 6.15 g).