摘要
采用氢氧化钠/尿素混合水溶液对木薯淀粉进行预处理活化,研究了预处理对木薯和松香酶法合成松香淀粉酯的影响。通过SEM、FT-IR和XRD等表征方法研究了预处理对木薯淀粉颗粒形貌和结晶结构的影响,结果表明,木薯淀粉经预处理后,淀粉粒仍保持一定圆形或椭圆形结构,但是其表面有破面和裂缝;预处理淀粉结晶结构遭到一定程度破坏,结晶度降低。对比分析木薯淀粉及预处理木薯淀粉的理化性质发现,预处理后的木薯淀粉在冷水中的溶解率由7.5%增加到45.7%,提高了38.2个百分点,透明度由86.6%增加到95.7%,增强了9.1个百分点,相对黏度降低。以松香为原料,固定化脂肪酶为催化剂,分别与木薯淀粉和预处理木薯淀粉进行酯化反应,考察预处理对酯化反应取代度的影响。结果表明,经预处理后的木薯淀粉与松香反应的取代度高达0.102,相比预处理前松香淀粉酯的取代度0.016明显提高。FT-IR分析表明,预处理后木薯淀粉酯化后的松香淀粉酯在1720 cm-1处产生明显的酯羰基CO伸缩振动吸收峰,其化学反应活性明显提高。
Pretreatment of cassava starch with NaOH/Urea and its effect on enzymatic synthesis of rosin starch ester were studied in this paper. The granule morphology and crystal structure of pretreated cassava starch were characterized by SEM,FT-IR,and XRD methods. The results showed that the granule of starch still maintained a certain round or oval morphological structure after pretreatment,but its surface was broken and exhibited some kinds of crack. The crystallinity of pretreated cassava starch was reduced. Based on the comparison of physicochemical properties between cassava starch and pretreated cassava starch,it was showed that the dissolution rate and transparency of pretreated cassava starch increased 38. 2 percent and 9. 1 percent,and the relative viscosity went down. Enzymatic esterifications of cassava starch and pretreated cassava starch with rosin were carried out.The degree of substitutions（ DS） of the esterifications were determined in order to investigate the effect of pretreatment on the reaction. The results indicated that pretreatment increased the degree of substitution of esterified products remarkably,and the DS value of 0. 102 was achieved. FT-IR analysis showed that a new peak at 1720 cm^-1was observed in the spectra of esterified products produced from pretreated cassava starch,which corresponded to C=O stretching in the ester group. The results indicated that the chemical reactivity of pretreated cassava starch increased significantly.
出处
《林产化学与工业》
EI
CAS
CSCD
北大核心
2015年第1期89-93,共5页
Chemistry and Industry of Forest Products
基金
广西高校人才小高地建设创新团队资助计划项目(桂教人[2011]47)
教育部留学回国人员科研启动基金资助项目([2012]1707)
广西民族大学研究生教育创新计划资助(gxun-chx2014097)
关键词
松香
木薯淀粉
预处理
酯化
固定化脂肪酶
rosin
cassava starch
pretreated
esterification
immobilized lipase
