Modification of physical and functional characteristics of chitin extracted from microwave-treated Nelumbo nucifera rhizome flour

Abstract

Chitin, a cell wall polysaccharide, extracted from Nelumbo nucifera rhizome (NNR), was subjected to microwave treatment to modify its physical and functional characteristics. The NNR flour was irradiated at different levels of the microwave treatment period (1, 2, 3, 4, and 5 min). Chitin was extracted from the native and microwave-treated samples and analyzed for physical and functional characteristics. The microwave treatment resulted in some variations in the extract yield, structure, morphology, and composition of chitin that were directly correlated with its functional properties. Regression analysis of the data showed a significant ( p < 0.05) time-dependent linear decrease in extract yield, polynomial decrease in water-holding and swelling capacities, an exponential increase in oil holding, and an exponential decrease in iron-binding capacity of chitin extracted from microwave-treated flour. These variations in the studied functional properties may be due to microwave-induced hydrolytic degradation of chitin, structural rearrangements, and exposure of some lipophilic functional groups on the surface of chitin. The data would be a valuable contribution to the literature regarding microwave-induced modification in physical and functional characteristics of chitin present in N. nucifera rhizome and other plant-based biomaterials of industrial importance.