Effect of starch-protein interaction on regulating the digestibility of waxy rice starch under radio frequency treatment with added CaCl2

Abstract

This study investigated the effect of starch-protein interaction on regulating the digestibility of waxy rice starch under radio frequency (RF) treatment with added salts. The results showed that starch-protein interactions could significantly reduce the digestibility of waxy rice starch (WRS) under synergetic Ca2+-RF treatment. With the increase of Ca2+ content (0–2 %), the resistant starch content of WRS-WPI, WRS-SPI and WRS-PPI increased from 35.53 %, 36.12 % and 38.78 % to 51.05 %, 52.82 % and 55.93 %, respectively. The addition of appropriate Ca2+ content could increase the short-range ordered structure and lamella structure and form a more compact and uniform microstructure. In addition, the interaction between WRS and protein was mainly through hydrogen bonding and hydrophobic interactions during RF treatment. Furthermore, the presence of Ca2+ could improve the distribution and mobility of water molecules and regulate the rheological properties of WRS-protein complexes. This study offers theoretical guidance for the design and production of rice starch-based products with lower digestibility.