FT-IR研究CMC、MCC对小麦淀粉的抗回生规律

Effects of CMC and MCC on Resisting Retrogradation Regularity and Mechanism of Wheat Starch by FT-IR

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。

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.