以玉米淀粉和油酸为原料,研究了无溶剂体系下油酸淀粉酯的酶催化合成.主要考察了酶与淀粉的质量比、反应温度、底物比、时间等参数对油酸淀粉酯取代度的影响.采用气相色谱法进行取代度的测定,并以取代度为考察指标,确定了最佳的工艺条件.在单因素试验的基础上进行正交试验,结果表明,最佳工艺条件为:酶的添加量为6％、温度70℃、底物质量比1∶7,在上述条件下反应12 h,取代度可达0.201.同时,使用紫外吸收光谱和FT-IR谱图对产物结构进行表征.%Oleic acid starch ester was synthesized by using immobilized lipase Novozym435 as the biocatalyst in the solvent - free system. Several factors, such as the ratio of lipase to starch, esterification temperature, esterification time and ratio of acyl donor and acceptor substrates has been investigated in the solvent - free system. A novel GC -based method was used to measure the degree of substitution ( DS) of oleic acid starch ester. DS as the research object was adopt to optimize the reaction conditions. According to the results of the single - factor experiments, the perpendicular experiments were designed to optimize the parameters of the reaction. The results showed that the optimum reaction conditions were as below: concentration of lipase was 6% ,the ratio of starch to oleic acid 1:7( W/W) ,the reaction temperature 70 ℃,the reaction time 12 h. A degree of substitution of 0. 201 was obtained. The structures of products were characterized by UV absorption spectra and FT - IR spectra.
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