Multiscale structure-property relationships of oxidized wheat starch prepared assisted with electron beam irradiation

In this study, two promising eco-friendly modification techniques, electron beam (EB) irradiation and hydrogen peroxide (H2O2) oxidation, were used to prepare oxidized wheat starch. Neither irradiation nor oxidation changed starch granule morphology, crystalline pattern, and Fourier transform infrared spectra pattern. Nevertheless, EB irradiation decreased the crystallinity and the absorbance ratios of 1047/1022 cm-1 (R1047/ 1022), but oxidized starch exhibited the opposite results. Both irradiation and oxidation treatments reduced the amylopectin molecular weight (Mw), pasting viscosities, and gelatinization temperatures, while increasing the amylose Mw, solubility and paste clarity. Notably, EB irradiation pretreatment dramatically elevated the carboxyl content of oxidized starch. In addition, irradiated-oxidized starches displayed higher solubility, paste clarity, and lower pasting viscosities than single oxidized starches. The main reason was that EB irradiation preferentially attacks the starch granules, degrades the starch molecules, and depolymerizes the starch chains. Therefore, this green method of irradiation-assisted oxidation of starch is promising and may promote the appropriate application of modified wheat starch.

Automated summary

Two eco-friendly modification techniques, electron beam irradiation and hydrogen peroxide oxidation, were used to prepare oxidized wheat starch in this study. Both techniques did not change the starch granule morphology, crystalline pattern, and infrared spectra pattern. However, electron beam irradiation decreased crystallinity and absorbance ratios, while oxidized starch showed the opposite results. Both treatments reduced amylopectin molecular weight, pasting viscosities, and gelatinization temperatures, while increasing amylose molecular weight, solubility, and paste clarity. Electron beam irradiation dramatically increased carboxyl content in oxidized starch. Additionally, irradiated-oxidized starches exhibited higher solubility, paste clarity, and lower pasting viscosities compared to single oxidized starches due to the degradation and depolymerization of starch chains caused by electron beam irradiation.