Effect of gelatinization processing on the antioxidant, digestion, and physicochemical properties of wheat starch enhanced with tannic acid

In this study, the effect of the gelatinization processing on the antioxidant capacity, starch hydrolysis rate, and physicochemical properties of wheat starch supplemented with 0.1%-0.5% tannic acid were investigated. It was found that wheat starch enhanced with tannic acid had a positive effect on the phenolic contents and antioxidant properties. The hydrolysis rate of wheat starch with tannic acid was significantly lower, showing a lower level of rapidly digestible starch (RDS) and slowly digestible starch (SDS). These improved functional properties may be caused by the inhibitory effect against digestive enzymes and the reassembled ordered microstructure of wheat starch. Moreover, the gelatinization processing promoted the release of polyphenols in the process of in vitro digestion, which enhanced the antioxidant capacity of wheat starch supplemented with tannic acid. Besides, the gelatinization processing increased the starch digestion rate, but did not influence the extent of the starch digestion. This suggested that the gelatinization processing does not give negative effect but even promote the nutritional value of tannic acid in wheat starch such as phenolic content and antioxidant activity.