Abstract:Effects of carboxymethylcellulose (CMC) and microcrystalline cellulose (MCC) on the retrogradation of wheat starch (WS) were investigated by DSC and fourier transform infrared spectroscopy (FT-IR). The result showed that the band of FT-IR at 3423 cm-1 shifted to low wavenumber, indicating that the intermolecular hydrogen bond was enhanced. The band shifted from 1647 cm-1 to 1641 cm-1 for WS/CMC and the band at 1647 cm-1 were not changed for WS/MCC. However, the characteristic peak of MCC at 1433 cm-1 disappeared. These results suggested that CMC or MCC was not simply mixed with WS, and the mixture systems resisted retrogradation by the intermolecular interaction. IR retrogradation degree (IRAD1047 = H1047/H1020, IRAD995 =H 995/H1020) of the peak intensity ratios were used to quantitative characterize the retrogradation degree changes, which was showed that 4.0% CMC resisted WS retrogradation better than 6.0%, and 6.0% MCC better than 4.0%. CMC was superior to MCC on retrogradation inhibition. Anti-retrogradation mechanism of WS/CMC and WS/MCC mixture pastes after cold storing for 14 d was also discussed. IR retrogradation degree (IRAD1047 and IRAD995) determined by FT-IR was consistent with the DSC results (DSCAD=?Hr/?H). FT-IR method has been found to be sensitive to chemical bond environments, which can get more and detailed information related to structures or properties quickly and easily.
