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酶法双甘酯的制备论文字数: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,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。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,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。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∶, lipase content 6%, reaction temperature 42℃, reaction time 4h. The DG content in the yield was 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∶, Lipase content 6%, reaction temperature 37℃, Ultrasonic power 50W and the reaction time 2h. The DG content in the yield was under the above words: Diacylglycerol(DG);Lipase;Glycerine Alcoholysis;Hydrolysis;Ultrasound 目 录1 绪论 1 前言 1 双甘酯的组成、结构与功能 1 双甘酯的组成与结构 1 双甘酯的生理功能 2 双甘酯的应用 3 双甘酯在食品添加剂中的应用 3 双甘酯在医药中的应用 4 双甘酯在化妆品中的应用 4 其他应用 4 双甘酯的各种制备方法 5 双甘酯的化学制备方法 5 双甘酯的酶法制备 6 双甘酯各种制备方法的特点分析 8 双甘酯的分析方法 9 超声波及其在酶促反应中的应用 10 超声波 10 超声波工作原理 11 超声波在酶促反应中的应用 12 课题研究内容 132 测定方法 14 样品制备 14 羟基值的测定 14 乙酰化试剂的配置 14 测定步骤 14 单甘酯的含量测定 14 游离甘油含量测定 15 游离脂肪酸的含量测定 15 双甘酯的含量 16 甘三酯的含量 163 酶促棕榈油甘油醇解、水解制备双甘酯 17 试验材料与仪器 18 试验材料 18 试验仪器 18 试验方法 18 酶促甘油醇解反应 18 酶促水解反应 19 结果与讨论 19 酶促甘油醇解反应影响因素 19 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 结论 234 超声场中酶促水解制备双甘酯 24 试验材料与仪器 24 试验材料 24 试验仪器 24 试验方法 25 结果与讨论 25 超声功率对双甘酯产率的影响 25 超声场与机械搅拌条件对比 26 结论 275 结论与展望 28 结论 28 存在的问题与展望 28参考文献 29Abstract 31 致 谢 32以上回答来自:

261 评论

小东家1985

保护节约能源是我们每个人的义务,那么有关保护能源的 英语 作文 怎么写呢?下面我为大家带来保护能源英语作文,欢迎大家学习!

Another round of energy crisis is knocking at the 2004,world oil consumption reached a new record,causing oil price in the international market to skyrocket for China,it was reported that many traditional mineral cities in northeastern China had run into predicament,with their economy collapsed and workers unemployed,only because coal had been mined out.

Fossil energy resources,including coal,oil and gas,are unlike sunlight,water power and wind power which are generated ’re not practically reproductive during human consumed,they’re gone they were to be exhausted before we could find sufficient reproductive resources to replace them with,we’d have to live in entire blackout again like our ancestors have done thousands of years ’s of course not what anyone would want to see.

Due to technical limitations,people still have to utilize these resources now.

As a result,we must economize them most techniques should be developed and applied to reduce energy cost in industry and daily energy should be employed wherever any practice that wastes have overcome so many crises in history,and we’re sure to win this time also.

china is rich in various energy resources. coal and petroleum, for instance, are two major trees. they ave essential in developing the country's industry, ,science and technology. china has done a great deal in the past few decades to raise the output of coal and petroleum.

these energy resources are being used up rapidly, however. with the building of four modernizations, new industrial and science projects axe springing up like bam booshoots after a spring rain. they are all enormous consumers of energy resources. be sides, there has been great waste in using these resources.

to avoid energy crisis in the future, the government must take measures. first, it should let the people know, through education, the importance of ,saving energy. sec ond, efforts should be made in opening up new energy resources, such as solar energy, geothermal energy and so on. we have reasons to be optimistic in this respect.

another round of energy crisis is knocking at the door. in 2004, world oil consumption reached a new record, causing oil price in the international market to skyrocket amazingly.

as for china, it was reported that many traditional mineral cities in northeastern china had run into predicament, with their economy collapsed and workers unemployed, only because coal had been mined out.

fossil energy resources, including coal, oil and gas, are unlike sunlight, water power and wind power which are generated consistently. they’re not practically reproductive during human history. once consumed, they’re gone forever.

if they were to be exhausted before we could find sufficient reproductive resources to replace them with, we’d have to live in entire blackout again like our ancestors have done thousands of years ago. that’s of course not what anyone would want to see.

due to technical limitations, people still have to utilize these resources now.

as a result, we must economize them most cleverly. new techniques should be developed and applied to reduce energy cost in industry and daily life. alternative energy should be employed wherever possible. eradicate any practice that wastes energy.

humans have overcome so many crises in history, and we’re sure to win this time also.

The earth is suffering, and we, the human beings, are suffering with it, rivers on the earth are drying,then we have to turn to the Mars to search for water;trees on the earth are reducing,then we have to use plastics;the oil,coal and gas is getting less an less,then we have to be ready to go backward to the hates the pollutions but everybody is making you are responsible person for the world,for the next generation and for yourself,then stop making such 's all together save the environment, save the resources ,save the nature and save the earth as because that is to save ourselves!Come on,do something with the preservation of the human existence.

Everybody knows that we have only one earth on which we share with different kinds of animals and the development of the industry,we, the human beings, have produced more and more pollutions whci are harmful to the animals,plants and ourselves as most serious problem that we have to face is that the earth is being destroyed by our so-called may find we are having more and more natural disasters on the is why some countries,like America,has begun to explore the Mars and the other save the earth is to save ourselves.

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3. 保护环境用英文怎么说

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5. 关于保护环境的英语句子

209 评论

louisbellen

哈哈, 我写完了。 很容易的,抄你实习日志北。

203 评论

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