Preparation of Black Soybean Peptide and Its Effect on Weight Reduction in Rats

The large-scale preparation method for black soybean peptide (BSP; about 70% less than 10,000 Da; highly enriched with glutamic acid, aspartic acid, and arginine) was developed, and its effect on weight reduction and lipid profiles in rats was investigated. Sprague-Dawleymale rats were assigned to four dietary groups (high-fat diets containing 0, 2, 6, and 10% BSP) and fed four weeks to examine the effects of BSP. During the experiment, food intake was measured every two days and body weight was monitored two times a week. After the supplementation of BSP, liver and adipose tissues (epididymal, retroperitoneal and perirenal adipose tissue) in the rats were weighted and the lipid profiles in serum, liver, and feces were analyzed. At the results of body weight gain, liver and epididymal adipose tissue weight, BSP groups were more decreased than HF group (0% BSP), with greater decreases at higher BSP levels. The same patterns were shown in lipid profiles of serum, as BSP was increased, triglyceride and total cholesterol concentration decreased. The serum HDL-cholesterol level was increased with increasing at BSP levels. Total cholesterol concentration of liver and feces were decreased and increased, respectively, as BSP increased. The results confirm that BSP is involved in reducing the body weight and the improvement of lipid composition in serum and liver of rats and that BSP can be applied in weight reduction in the food products industry.