The physiological effects of the hydrolysates of white rice
protein (WRP), brown rice
protein (BRP), and
soy protein (SP) hydrolyzed by the food grade
enzyme, alcalase2.4 L, were compared to the original
protein source. Male Syrian Golden hamsters were fed high-fat diets containing either 20%
casein (control) or 20% extracted
proteins or their hydrolysates as the
protein source for 3 weeks. The brown rice
protein hydrolysate (BRPH) diet group reduced
weight gain 76% compared with the control. Animals fed the BRPH supplemented diet also had lower final
body weight, liver weight,
very low density lipoprotein cholesterol (VLDL-C), and liver
cholesterol, and higher fecal fat and
bile acid excretion than the control. Expression levels of hepatic genes for
lipid oxidation, PPARĪ±, ACOX1, and CPT1, were highest for hamsters fed the BRPH supplemented diet. Expression of CYP7A1, the gene regulating
bile acid synthesis, was higher in all test groups. Expression of CYP51, a gene coding for an
enzyme involved in
cholesterol synthesis, was highest in the BRPH diet group. The results suggest that BRPH includes unique
peptides that reduce
weight gain and hepatic
cholesterol synthesis.