Abstract
“Okara” which is rich in protein and fiber, is a by-product of soy milk and soybean curd. In this stuay, the effects of “Okara” on cholesterol metabolism in rats were examined. For 4 weeks, male Sprague-Dawley rats were fed with a cholesterol-rich diet containing 10-30% of dried “Okara” or 2.2-5.6% of neutral detergent fiber (NDF) which was prepared from “Okara. ”
Supplementation of “Okara” accelerated food intake and body weight gain of rats. As compared with control rats, the animals given “Okara” showed significantly lower levels of plasma cholesterol, and the ratio of HDL-cholesterol to total cholesterol of plasma was increased significantly. The triglyceride and phospholipid contents of plasma were decreased by “Okara” feeding. The cholesterol and triglyceride contents of liver were tended to increase after supplement of “Okara. ” Fecal excretion of cholesterol was not affected by the feeding of “Okara. ”
The effect of dietary NDF was quite different from that of “Okara. ” NDF did not affect the levels of plasma cholesterol, while the fecal excretion of neutral sterols was increased after the NDF feeding.
From these results, “Okara” was found to have a property to restrain the increase of plasma cholesterol, However, NDF was not shown to have such an effect. The hypocholesterolemic effect of “Okara” is regarded to be originated from the coexistence of soya protein and fibers, especially water-soluble ones.
