[关键词]
[摘要]
利用DSC和傅里叶变换红外光谱(FT-IR)研究羧甲基纤维素(CMC)和微晶纤维素(MCC)对小麦淀粉(WS)回生的影响。结果表明:当CMC和MCC添加到WS中后,FT-IR中3423 cm-1峰向低波数方向位移,表明分子间氢键增强;WS/CMC体系中的1647 cm-1移动至1641 cm-1;WS/MCC中1647 cm-1未发生位移,MCC的特征峰1433 cm-1消失;表明CMC和MCC与WS不是简单混合,其分子间发生相互作用,使体系具有抗回生作用;并用红外回生度(IRAD1047 = H1047/H1020,IRAD995 =H 995/H1020)峰强度比定量表征了回生程度变化,表明添加4.0% CMC对WS抗回生比6.0%高,而添加6.0% MCC比4.0%的抗回生高;CMC对WS回生的抑制作用优于MCC;讨论了WS/CMC及WS/MCC混合体系糊化后冷藏14 d后抗回生的机理;红外回生度(IRAD1047、IRAD995)和经典的DSC回生度(DSCAD=?Hr/?H)比较:FT-IR所得到的红外回生度与DSC回生度变化规律一致;FT-IR对化学键周围的环境更加敏感;能够快速、容易得到更多和详细的相关结构与性能信息。
[Key word]
[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.
[中图分类号]
[基金项目]
国家自然科学基金资助(51043011;31270617);高分子材料工程国家重点实验室开放课题基金资助(KF201301)