Effects of varied preparation processes on polyphenol-rice starch complexes, in vitro starch digestion, and polyphenols release

In this study, we synthesized composite samples incorporating four representative polyphenolic structures, gallic acid (GA), quercetin (QC), resveratrol (RES), and magnolol (MN), with rice starch using various preparation processes, including the addition of polyphenols and alteration of temperature and pH, via co-gelatinization. Subsequently, the complexation rates, starch digestion properties, and polyphenol release during in vitro digestion. The results indicated that both the preparation process and structural variations of polyphenols affected starch digestion and polyphenol release by modulating the complexation. All polyphenols displayed inhibitory effects on rice starch digestion, with GA being the most efficient polyphenol. Additionally, rice starch exhibited a protective effect against RES during in vitro digestion, as rice starch-coated RES reduced the damage from stomach acids. This study may help optimize the processing conditions for the synthesis of polyphenol-rice starch-based food products.