醚化交联淀粉变温合成及其碘复合物吸收光谱分析

Study on synthesis of etherified cross-linked starch by variable temperature method and absorption spectrum analysis of starch-iodine complex

以木薯淀粉为原料,环氧氯丙烷(ECH)为交联剂,采用变温交联法制备醚化交联淀粉,对淀粉交联反应机理进行了分析。通过正交实验探讨了交联剂用量、pH、反应温度、反应时间对交联淀粉沉降积的影响,确定了制备高交联淀粉的最佳工艺条件为:pH11,ECH用量为0.3%(w/w),先在35℃下反应3h,然后升温至50℃反应0.5h。应用淀粉-碘复合物吸收光谱对不同交联度淀粉的结构进行表征,结果表明:交联反应改变了直链淀粉构象,影响了碘分子进入其内部,相应的络合碘分子数目减少,颜色变浅,吸光值减小,最大吸收波长向较短波长方向移动。

Etherification cross-linking starch were prepared through variable temperature cross-linking of cassava starch and epichlorohydrin（ ECH）.The mechanism of cross-linking of starch by ECH was analyzed.The effects of the amount of cross-linking agent, pH value, reaction temperature and time on the sediment volume（VSE） of cross -linking starch were investigated.The optimal conditions for synthesis of high cross-linked starch were obtained by orthogonal experiment as follows：pH 11, amount of ECH 0.3% （w/w） ,first,3h of reaction at the temperature of 35℃,then 0.5h at 50℃.The cross-linked starch＇ s structures were characterized at different degrees of cross- linking with absorption spectrum of starch-iodine complex. The results indicated that cross-linking reaction changed the conformation of amylose, and affected iodine to get into it.The number of corresponding starch-iodine complex decreased,the color became shallow, absorbance decrease and maximum absorption wavelength shift towards shortwave direction.