The effects of retrograded rice on
body weight gain, gut functions, and hypolipidemic actions in rats were examined. When the retrograded rice was produced by repetitive heating and cooling cycles, it contained significantly higher amounts of
resistant starch (13.9 ± 0.98%) than is found in common rice (9.1 ± 1.02%) (P < 0.05). Sprague-Dawley rats were fed either common rice
powder or retrograded rice
powder, and mean
body weight gain was significantly lower in the retrograded rice group (P < 0.05). The liver weight of the retrograded rice group (14.5 ± 0.5 g) was significantly lower than that of the common rice group (17.1 ± 0.3 g, P < 0.05). However, the weights of other organs, such as the kidney, spleen, thymus, and epididymal fat pad were not significantly affected by rice feeding. Intestinal transit time tended to be lower in rats fed retrograded rice when compared to rats fed the common rice, but the difference was not significant. The retrograded rice diet significantly increased stool output when compared to that in the common rice
powder diet (P < 0.05), whereas fecal moisture content (%) was significantly higher in the retrograded rice group (23.3 ± 1.2) than that in the common rice group (19.1 ± 1.2) (P < 0.05). The retrograded rice group had significantly lower plasma
cholesterol (P < 0.05), liver
cholesterol (P < 0.05), and
triacylglycerol contents in adipose tissue (P < 0.05) when compared to those in the common rice group. In conclusion, retrograded rice had higher
resistant starch levels compared with those of common rice
powder, and it lowered
body weight gain and improved
lipid profiles and gut function in rats.