Impact of Cooking on Starch Digestibility in Foxtail Millets

While the digestibility of millet starch has been studied considerably, the effects of cooking on starch digestibility in millet remain insufficiently understood. This study investigated the effects of cooking on in vitro enzymatic starch digestion in eight cooked millet flour cultivars by seeking its correlations with the changes in composition (moisture, total starch, protein, lipids, total dietary fiber, and phenolics), structure, and physicochemical properties. Compared to raw flours, cooked flours had a similar content of total starch and protein, a lower content of moisture, lipids, and total phenolic content, and a higher content of total dietary fiber. Cooking disrupted starch granules and crystalline structures in all eight millets, promoting the formation of starch-lipid complexes and reducing the paste viscosity (except for CS07). The in vitro starch digestion of eight millet flours were lower than that of rice flour. Correlation analysis results revealed that in vitro starch digestibility in cooked millet flours was related to the amounts of starch-lipid complexes and the total dietary fiber content. These findings demonstrated that interactions between starch and other components during cooking are the key determinants for the digestion of starch in cooked foods.