Microwave Assisted Cooking Improves Edible Quality of Germ Rice: Insights of Multiscale Starch Microstructure, In Vitro Digestion, and Flavor

Germ rice is a moderately processed products with high germ retention rate (>80%). Electric rice-cooker and microwave cooking as the most common cooking methods have different effects on starch microstructures, digestibility, rheological behavior, texture, and flavor of germ rice. Microwave-cooked germ rice contains more short-range ordered structures and higher crystallinity than electric rice-cooker cooked germ rice. The starch digestibility of germ rice (i.e., rapidly digestible starch) cooked by microwave under different power and time (50.74%-52.47%) is lower than that of electric rice-cooker cooked by two modes (60.52%-60.82%). The rheology (modulus and shear viscosity) of germ rice treated by electric rice-cooker is higher than that treated by microwave. Microwave-cooked germ rice has lower adhesiveness (164-212 g s) than that cooked in electric rice-cooker (286-295 g s). Aldehydes are the most abundant volatile components, and play a very important role in germ rice flavor. Microwave cooking can reduce the digestibility of starch and improve the flavor of cooked germ rice. Microwave is expected to be a promising cooking technique for germ rice cooking.