Submitted to: Journal of Food Chemistry
Publication Type: Peer reviewed journal
Publication Acceptance Date: 5/25/2010
Publication Date: 6/1/2010
Citation: Villanueva, M., Yokoyama, W.H., Hong, Y., Bartley, G.E., Ruperez, P. 2010. EFFECT OF HIGH-FAT DIETS SUPPLEMENTED WITH OKARA SOYBEAN BY-PRODUCT ON LIPID PROFILES OF PLASMA, LIVER AND FAECES IN SYRIAN HAMSTERS. Journal of Food Chemistry. Doi:10.1016/j.foodchem.2010.05.106. Interpretive Summary: Okara is a byproduct of soy food processing that is high in dietary fiber, protein and isoflavones. Both dietary fiber and protein are known to reduce plasma cholesterol. The study was conducted to determine whether dietary fiber, protein or isoflavones reduced cholesterol. Diets containing 20% okara reduced plasma total and non-HDL cholesterol. Diets containing 13% okara had no significant effect but indicated that fiber had the most effect and protein some effect but no effect from isoflavones.
Technical Abstract: The main components of okara, a by-product from soybean, is dietary fiber and protein. Both dietary fiber and protein can reduce plasma cholesterol. In this study we fed okara based diets with different amounts of fiber, protein and isoflavones to determine the most important component for cholesterol lowering. Male golden Syrian hamsters were fed high-fat diets supplemented with okara for three weeks. The supplemented diets contained 13% or 20% of okara fiber (OK-13 and OK-20), low-protein okara with 13% of fiber (OK1-13) and isoflavone-free okara with 13% of fiber (OK2-13). Okara supplemented diets did not produce significant differences in food intake or body weight gain. The plasma levels of triglycerides and VLDL- plus LDL-cholesterol and total cholesterol in hamsters fed OK-20 decreased significantly (p<0.05) with respect to the 20% fiber control group (C-20). However, plasma LDL and HDL-cholesterol levels were not significantly different (p>0.05) in any okara supplemented diet. Total fat, triglycerides, total and esterified cholesterol concentrations in liver were reduced by OK-20. All of the okara supplemented diets increased fecal excretion of fat, triglycerides, free cholesterol and fecal protein (p<0.05) compared to their respective controls. The levels of lipoprotein cholesterol fractions of the control (C-13) and low-protein Okara (OK1-13) were similar, and tended to be higher than the starting okara diet (OK-13) but the difference was not significant. From this study we conclude that both fiber and protein play a role in lowering plasma cholesterol in fat fed hamsters.