Gamma radiation modification of cassava starch and its characterization

Abstract

AbstractRadiation technology has been recognized as a potential tool to modify starches in order to enhance their solubility and enzymatic digestion, hence improving their applicability in food industry. In the present study, the local cassava starch was irradiated under 60Co gamma source with the absorbed dose ranging from 1 to 10 kGy, and the obtained radiation‐modified starches were characterized. The microstructure of the initial cassava starch was not much changed although several starch granules were deformed or even fragmented by gamma irradiation as observed in the scanning electron microscopy images. Water solubility of the irradiated starch was significantly increased, and their viscosity was much reduced by radiation degradation. Gamma radiation broke glycosidic bonds in starch chains into smaller molecules with lower molecular weight, whereby increased the water solubility of cassava starch. Radiation scission also partly decreased the crystallinity of the starches irradiated with dose higher than 5 kGy as indicated in their X‐ray diffraction patterns. The Fourier transform infrared spectra of irradiated starches revealed the reduction in intensities of stretching vibration characterized for OH, CH, and COC groups of starch molecules. Thus, gamma irradiation can be used to modify cassava starch for further applications.