交联羧甲基复合变性木薯淀粉的制备及性质

Preparation and Properties of Crosslinked Carboxymethyl Cassava Starch

本实验以木薯淀粉为原料,用环氧氯丙烷作交联剂,氯乙酸作羧甲基化试剂,合成了交联-羧甲基复合变性淀粉。采用铜盐沉淀法测其取代度,筛选出了交联-羧甲基复合变性淀粉合成工艺的最佳条件为:反应温度55℃,反应时间4h,配料质量比淀粉:氯乙酸:氢氧化钠=1.00:0.44:0.44;在此条件下合成的产品取代度(DC)为0.79。与原木薯淀粉相比,交联-羧甲基反应后产物黏度增大,膨胀凝固性、热稳定性、透明度得到改善,具有较强的环境适应性和良好的应用性能。红外光谱分析发现,在1008～1164cm-1的吸收峰强度加强,证实在淀粉中引入了羧甲基。DSC分析表明,交联-羧甲基淀粉有较高的糊化温度,且更易糊化。

The crosslinked carboxymethyl double modified starch （CCMS） was made from cassava starch with epichlorohydrin as crosslinking agent and chloroacetic acid as carboxyme thylating agent. The degree of substitution of product was determined by the precipitation method of copper salt. The optimal conditions are as follows： reaction temperature 55 ℃, reaction time 4 h and ratio of starch：CICH2COOH：NaOH 1.00：0.44：0.44. The DS is about 0.79 under these conditions. Compared with native starch, CCMS shows higher viscosity, paste transparency and thermostability. CCMS possess the stronger environment adaptability with good application performance. The FTIR results showed that the peak at 1008- 1164 cm^-1 is enhanced, indicating the group of carboxymethyl has been introduced in starch molecule. The DSC results indicated that cross-linked carboxymethyl starch has a higher gelation temperature and can be gelated more easily.