Impacts of electron-beam-irradiation on microstructure and physical properties of yam (Dioscorea opposita Thunb.) flour

Abstract

In this study, Chinese yam (Dioscorea opposita Thunb.) flour was irradiated at doses of 1.79, 6.06, 10.07 and 14.97 kGy of the electron beam, to analyze the effects of electron beam irradiated (EBI) on the solubility, transmittance, swelling, paste properties, and the microstructure of starch in yam flour. Results showed that EBI degraded the starch component of yam flour, and presented an increase in solubility from 15.59 to 30.05%, transmittance from 8.11 to 11.63%, and a decrease in swelling from 9.59 to 7.26 g/g. Also, we observed that there was a significant decrease in the paste properties of yam flour with the elevation of EBI. The scanning electron micrographs and Fourier transforms infrared spectra further illustrated the effect of EBI on the molecular structure, but not the surface structure of starch in yam flour. C-type crystalline structure in yam starch was also observed in both control and treatment, while irradiated yam starch had a lower crystallinity than that of unirradiated treatments. Yam starch exhibited a decrease trend in their thermal property values with irradiation treatment. This study concludes that the physical properties of yam flour instructed by EBI may be used in a wide application in the food and pharmaceutical industrie.