Effects of Lactic Fermentation Processing of Soymilk and Okara on Lipid Metabolism in Rats

This study examined the effects of fermented soymilk and okara on lipid metabolism in rats. Fermented soymilk and okara was prepared from a mixture of soymilk and okara blended in a ratio of 2 to 1 on dry basis by lactic acid fermentation using Lactobacillus delbrueckii. Male Sprague-Dawley rats were fed a diet based on the AIN-93 diet（ control diet） or two kinds of test diets in which 20% of a control diet was replaced by unfermented soymilk/okara mixture or fermented soymilk/okara for 7 weeks. We investigated changes in plasma and hepatic lipid levels of rats, and the regulation of gene expression in mesenteric adipose tissue and liver by DNA microarray. Groups of test diet significantly reduced plasma cholesterol levels compared with the control diet. In addition, the hepatic triglyceride in rats fed test diets was significantly lower than that of control diet. DNA microarray analysis indicated that the test diet ingestion down-regulated the expression of genes related to lipid metabolism in mesenteric adipose tissue and liver. These results suggested that a mixture of soymilk and okara has the effect improving lipid metabolism. Especially, fermented soymilk and okara seems to promote the restraint of abdominal visceral fat accumulation in comparison with unfermented soymilk and okara. Therefore, fermented soymilk and okara is a functional food showing effect preventing metabolic syndrome