Cooling of Cooked Starch
EFFECT OF COOLING OF COOKED WHITE RICE ON RESISTANT STARCH CONTENT AND GLYCEMIC RESPONSE
Cooling of cooked starch is known to cause starch retrogradation which increases resistant starch content. This study aimed to determine the effect of cooling cooked rice on resistant starch content and glycemic response in healthy subjects. Resistant starch contents were analyzed on freshly cooked white rice (control rice), cooked white rice cooled for 10 hours at room temperature (test rice 1), and cooked white rice cooled for 24 hours at 4 degrees Celsius then reheated (test rice 2). The results showed that resistant starch contents in control rice, test rice 1, and test rice 2, were 0.64g/100g, 1.30 g/100g, and 1.65g/100g, respectively. Test rice 2 had higher resistant starch content than test rice 1, hence used in the clinical study along with control rice to characterize glycemic response in 15 healthy adults. The clinical study was a randomized, single-blind crossover study. In the clinical study, test rice 2 significantly lowered glycemic response compared with control rice (125+50.1 vs 152+48.3 mmol.min/L, respectively; p=0.047). In conclusion, cooling of cooked white rice increased resistant starch content. Cooked white rice cooled for 24 hours at 4 degrees Celsius then reheated lowered glycemic response compared with freshly cooked white rice.