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 of cooked white 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 I), and cooked white rice cooled for 24 hours at 4°C then reheated (test rice II). The results showed that resistant starch contents in control rice, test rice I, and test rice II were 0.64 g/100 g, 1.30 g/100 g, and 1.65 g/100 g, respectively. Test rice II had higher resistant starch content than test rice I, 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 II 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°C then reheated lowered glycemic response compared with freshly cooked white rice. 煮熟的淀粉冷却会导致淀粉老化，导致抗性淀粉含量增加。该研究旨在确定冷 却煮熟的白米饭抗性淀粉含量和对健康人群血糖水平的影响。分析刚煮熟白米 饭（对照大米）、白米饭常温冷却10 小时（试验大米I）和白米饭在4°C 中 冷却24 小时后再加热（试验大米II）3 种状态下抗性淀粉含量。结果表明： 对照大米、试验大米I 和试验大米II 抗性淀粉含量分别为0.64 克/100 克、1.30 克/100 克和1.65 克/100 克。试验大米II 比试验大米I 抗性淀粉含量高，因此 在临床研究中，用对照大米作对照，研究了15 名健康成人血糖对试验大米II 的应答。该临床研究是一项随机、单盲交叉的研究。在临床研究中，试验大米 II 比对照大米能显著降低血糖应答（125±50.1 vs 152±48.4 mmol.min/L， p=0.047）。总之，冷却的熟白米饭增加抗性淀粉含量。与刚煮熟的白米饭相 比，煮熟的白米饭在4°C 中冷却24 小时然后加热，能降低血糖应答。.