Dialdehyde Oxidation of Cross-Linked Waxy Corn Starch: Optimization, Property and Characterization

The functionalization of waxy corn starch (WCS) was better realized by combing the cross-linking of epichlorohydrin with oxidation of sodium periodate. The results indicated that the cross-linking had a greater influence on the retrogradation than the oxidation, and the oxidation worsened the freeze–thaw stability of WCS. Both cross-linking and oxidation could ameliorate the alkali and acid resistance of WCS, and enhanced its heat stability. Cross-linking weakened the absorption peak of the –OH groups according to FTIR and had a small influence on the crystalline configuration of WCS belonging to a typical A-type structure, whereas the oxidation almost entirely damaged the particle structure. After the cross-linking, the tiny pits with a diameter of around 1 μm only appeared on sides of WCS granules, and proving that the cross-linking was very unevenly completed on some of WCS particles. The pasting curve of WCS was obviously different from those of its derivatives. The combination of oxidation and cross-linking could effectively decrease the setback of WCS.