Microwave-Induced Modification in Physical and Functional Characteristics and Antioxidant Potential of Nelumbo nucifera Rhizome Starch

The microwave-induced modifications in physical characteristics, functional properties, and antioxidant potential of Nelumbo nucifera rhizome starch were studied. The rhizome flour was subjected to microwave irradiation at different treatment times (1, 2, 3, 4 and 5 min) at the low-medium intensity (200 W). The starch was obtained from the native and microwave treated flour and analyzed for its physical characteristics, functional properties, and antioxidant potential. The microwave treatment showed a significant (p < 0.05) decrease in total starch yield and oil holding, swelling, and iron-binding capacity of the starch. Microwave treatment resulted in disruption of morphology and conversion of C-type crystalline structure to C A and C B -type structures of starch. The variations in antioxidant properties of starch were associated with the microwave-induced modification in the structure and physical characteristics of starch. A significant time-dependent increase in the content of reducing monosaccharides, Trolox equivalent total antioxidant activity, and free radical scavenging capacity was observed in microwave treated starch. The data may be a valuable contribution to the literature regarding microwave-induced modification in physical, functional and antioxidant properties of lotus rhizome starch.