Functions of high glycemic index carbohydrates: Exploring the effect of amorphous rice starch digestibility on glycometabolism.

The digestive characteristics of amorphous starch in cooked rice have rarely been studied from a metabolic perspective. This study explores the effects of cooked rice starch on glycometabolism in rats to explore the role of high glycemic index (GI) carbohydrates in the daily diet. Utilizing X-ray diffraction and Fourier transform infrared spectroscopy allowed the structure of amorphous starch to be probed, while rats were subjected to a long-term pre-prandial gavage intervention (glucose as a positive control and normal saline as a negative control) to assess the effects of high GI carbohydrates on glucose tolerance, insulin sensitivity, and markers of glucose metabolism in skeletal muscle (SIRT1, PGC-1α, GSK-3β, GLUT4). Results showed that high-GI carbohydrates significantly enhanced systemic insulin sensitivity, glucose tolerance, and skeletal muscle glucose metabolism. Waxy rice starch (WRS), containing a high amylopectin content (98.57 %), was found to be particularly effective due to its high rapidly digestible starch (RDS) content (66.01 %) and a GI of 102 after cooked into an amorphous state. Consequently, it can be concluded that a long-term moderate intake of amorphous rice starch induces the body to increase insulin sensitivity and improve glycometabolism. These findings emphasize the functional characteristics of high-GI starchy foods, offering a more profound understanding of carbohydrate-based diets.