酶法双甘酯的制备

论文编号:HG020  本论文字数:19829,页数:36

摘        要
 双甘酯（Diacylglycerol, DG）是甘三酯（Triacylglycerol, TG）中的一个脂肪酸被羟基取代的结构脂质。双甘酯是天然植物油脂中的微量成分及体内脂肪代谢的内源中间产物，它是公认安全(GRAS)的食品成分。近年来的研究表明, 双甘酯具有许多独特的生理作用和物化性质, 可广泛地应用于食品、医药、化妆品及其他化工产品, 是一类很有开发前景的新型化工原料。本论文主要对双甘酯的酶促甘油醇解、水解以及超声波外力场辅助酶促水解制备进行了研究。
 首先研究了酶促棕榈油甘油醇解反应制备双甘酯，研究表明：在搅拌、棕榈油与甘油底物摩尔比为2：1、加酶量为油脂质量的8%、甘油加水量0%、反应温度42℃的条件下，酶促甘油解制备双甘酯反应较慢，反应30小时，DG的质量分数才达40%。试验同时发现，体系中游离脂肪酸生成速率较快，尤其在前12小时。体系中没有加入水，参与反应的水主要源于酶中以及油脂中已有的水分，这二者的水分含量均不高，在此情况下，水解反应却较快，这说明，酶催化水解反应的能力很强。既然酶催化水解易于进行，因此，下文进行了酶促水解制备DG的研究。
 试验显示，在机械搅拌条件下，酶促水解的最优条件为：底物摩尔比（水∶棕榈油）为1.1，加酶量为油脂质量的6%，反应温度42℃，反应时间4h，产物中双甘酯的含量达到42.6%。该试验表明，酶促水解反应比甘油醇解反应快得多，且双甘酯产率高。
 为了进一步加快反应速率，本文在超声波作用下，对脂肪酶催化棕榈油水解制备双甘酯进行了试验。试验结果表明：在底物摩尔比（水∶棕榈油）为1.1，加酶量为油脂质量的6%，反应温度为37℃，超声功率为50W，仅需反应2h，产物中双甘酯的含量即达到50.72%。
关键词：双甘酯  脂肪酶  甘油醇解  水解  超声波

The Preparation of Diglyceride catalized by Enzyme
 Abstract: Diglyceride (DG) is a kind of structured lipid that hydroxyl replace acyl in the sn-1, 2, 3 position of triglyceride (TG). DG is a natural minor component of various edible oils and the endogenetic intermediate metabolite of lipid. Moreover, it is generally recognized as safe (GRAS) by FDA. Recent investigations have shown that diglyceride can be extensively applied to food, pharmaceuticals, cosmetics and other chemical products due to its specific physiological actions and physico-chemical properties. Diglyceride is one kind of new and promising chemical product. In this paper, the preparation of DG in different conditions were studied.
 Firstly, the preparation of DG by enzymatic glycerine alcoholysis of palm oil was studied. The research indicated that the DG content in the yield was only about 40% under the following conditions: mechanical agitation, ratio of palm oil to glycerol 2：1，lipase content 8%, water content of glycerol 0%，reaction temperature 42℃ and reaction time 30h. At the same time，the results show that the ability of enzymatic hydrolysis reaction is strong compared to the enzymatic glycerine alcoholysis reaction.
 Secondly, the preparation of DG by enzymatic hydrolysis of palm oil under the mechanical agitation condition was studied. The optimum reaction conditions were got by single-factor experiments and they are as follows: ratio of palm oil to water 1∶1.1, lipase content 6%, reaction temperature 42℃, reaction time 4h. The DG content in the yield was 42.62% under the above conditions.
 Thirdly, the preparation of DG by enzymatic hydrolysis of palm oil in the ultrasonic field were studied. The optimum reaction conditions are as follows: ratio of palm oil to water 1∶1.1, Lipase content 6%, reaction temperature 37℃, Ultrasonic power 50W and the reaction time 2h. The DG content in the yield was 50.72% under the above conditions.
Key words: Diacylglycerol(DG);Lipase;Glycerine Alcoholysis;Hydrolysis;Ultrasound

目 录
1  绪论 1
 1.1  前言 1
 1.2  双甘酯的组成、结构与功能 1
 1.2.1  双甘酯的组成与结构 1
 1.2.2  双甘酯的生理功能 2
 1.3  双甘酯的应用 3
 1.3.1  双甘酯在食品添加剂中的应用 3
 1.3.2  双甘酯在医药中的应用 4
 1.3.3  双甘酯在化妆品中的应用 4
 1.3.4  其他应用 4
 1.4  双甘酯的各种制备方法 5
 1.4.1  双甘酯的化学制备方法 5
 1.4.2  双甘酯的酶法制备 6
 1.4.3  双甘酯各种制备方法的特点分析 8
 1.4.4  双甘酯的分析方法 9
 1.5  超声波及其在酶促反应中的应用 10
 1.5.1  超声波 10
 1.5.2  超声波工作原理 11
 1.5.3  超声波在酶促反应中的应用 12
 1.6  课题研究内容 13
2  测定方法 14
 2.1  样品制备 14
 2.2  羟基值的测定 14
 2.2.1  乙酰化试剂的配置 14
 2.2.2  测定步骤 14
 2.3  单甘酯的含量测定 14
 2.4  游离甘油含量测定 15
 2.5  游离脂肪酸的含量测定 15
 2.6  双甘酯的含量 16
 2.7  甘三酯的含量 16
3  酶促棕榈油甘油醇解、水解制备双甘酯 17
 3.1  试验材料与仪器 18
 3.1.1  试验材料 18
 3.1.2  试验仪器 18
 3.2  试验方法 18
 3.2.1  酶促甘油醇解反应 18
 3.2.2  酶促水解反应 19
 3.3  结果与讨论 19
 3.3.1  酶促甘油醇解反应影响因素 19
 3.3.2  酶促水解反应影响因素 20
 （1）反应时间对双甘酯产率的影响 20
 （2）加酶量对双甘酯产率的影响 20
 （3）反应温度对双甘酯产率的影响 21
 （4）底物摩尔比对双甘酯产率的影响 22
 3.4  结论 23
4  超声场中酶促水解制备双甘酯 24
 4.1  试验材料与仪器 24
 4.1.1  试验材料 24
 4.1.2  试验仪器 24
 4.2  试验方法 25
 4.3  结果与讨论 25
 4.3.1  超声功率对双甘酯产率的影响 25
 4.3.2  超声场与机械搅拌条件对比 26
 4.4  结论 27
5  结论与展望 28
 5.1  结论 28
 5.2  存在的问题与展望 28
参考文献  29
Abstract  31 
致    谢  32