Exploring the Digestion Behavior of Amorphous Rice Starch: A Holistic Perspective from Hydrocolloid Formation to Metabolism

This study investigates the applicability of first-order enzymatic kinetics in the digestion of amorphous rice starch hydrogels. Structural characterization revealed that increased starch concentration enhances short-range molecular order, which significantly reduces enzymatic digestibility. Using a modified INFOGEST protocol, and rat experiment, both in vitro and in vivo digestion behaviors were comprehensively analyzed. Results showed that as concentration increased, the digestion rate constant (k) decreased notably, and the kinetic model shifted from first-order to zero-order. Animal metabolic experiments further supported this kinetic deviation, indicating a strong relationship between hydrocolloid structure and metabolic response. These findings highlight the limitations of using traditional first-order kinetics to describe starch digestion, suggesting that hydrocolloid concentration is a critical factor affecting digestion and metabolism. This study offers a more comprehensive approach to understanding starch behavior, with implications for dietary starch design and metabolic health research.