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1.
脂肪酶在食品中的应用已有几十年的历史,由于油脂中三酰甘油的1,3位和2位的脂肪酸对油脂的理化、营养和生理特性方面有较大的差异,因此专一性水解三酰甘油1,3位的脂肪酶成为研究的热点。由于sn-1,3位专一性脂肪酶选择性地水解三酰甘油的1位和3位,因此广泛的用于三酰甘油的修饰。国内外大量的研究表明,sn-1,3位专一性脂肪酶适用于生产结构脂质、母乳脂肪替代品、类可可脂和甘油二酯等,获得价格低廉而活性高的酶、高效的酶固定化技术和研发酶反应器是今后研究的重点。  相似文献   

2.
《粮食与油脂》2013,(5):1-4
脂肪酶高选择性催化主要包括两方面:一是Sn–1,3位置选择性催化;二是手性选择性催化,近几年,这两方面研究已成为脂肪酶研究热点。该文从脂肪酶如何选择性催化及如何提高其选择性催化活性等方面进行综述,以期能为更好利用和改进脂肪酶选择性提供思路。  相似文献   

3.
1,3-甘油二酯是一种健康油脂,并且可用来合成药物的中间材料,但其在天然油脂中含量有限。所以本文用黑曲霉GZUF36全细胞脂肪酶法甘油解合成了1,3-甘油二酯,重点探讨了影响其合成的关键因素:水活度。控制水活度的方法包括用饱和盐溶液平衡酶粉、水合盐平衡反应体介质、水合盐控制水活度水合盐分别预平衡酶粉和反应介质。结果表明,水活度显著地影响1,3-甘油二酯的产量和脂肪酶对1,3-甘油二酯的选择性。过高或过低的水活度都不利于全细胞脂肪酶GZUF36催化甘油解反应合成1,3-甘油二酯,水活度过低会导致酶活力不高,水活度过高则易使催化反应向水解方向进行。当用aw=0.58的水合盐分别预平衡酶粉和反应介质时,1,3-甘油二酯的得率和脂肪酶对1.3-甘油二酯的选择性都为最优,分别是26.100%和83.056%。本文为进一步优化全细胞脂肪酶GZUF36催化的选择性合成1,3-甘油二酯中的反应体系奠定了基础。  相似文献   

4.
目的:提高延黄牛脂的附加值。方法:采用固定化脂肪酶Lipozyme RM IM为催化剂,牛油脂肪酸乙酯(乙醇解法自制)和甘油为原料制备1,3-甘油二酯,运用氢谱考察脂肪酶添加量、底物摩尔比、反应时间以及反应温度对粗反应混合物中1,3-甘油二酯含量的影响,并阐明醇解酯交换前后牛油与甘油二酯产物的脂肪酸组成变化。结果:1,3-甘油二酯合成最佳条件为脂肪酶Lipozyme RM IM质量分数为1%,底物摩尔比(n脂肪酸乙酯∶n甘油)2∶1,反应时间6 h,反应温度50℃。此条件下的1,3-甘油二酯生成率为72.5%,甘油酯得率为77%;纯化后纯度提高至90.79%。与原油(延黄牛脂)相比,甘油二酯产物中亚油酸和油酸含量分别升高了13.65%,6.47%,饱和度降低了7.17%。结论:延黄牛脂制备1,3-甘油二酯不仅能改变甘油酯结构,还可以改变牛脂的脂肪酸组成,降低其饱和度。  相似文献   

5.
在无溶剂体系中,通过脂肪酶Novozyme 435催化甘油解法合成功能性油脂1,3-甘油二酯。在底物摩尔比1∶1(甘油与天然谷物调和油比),脂肪酶添加量8%(占底物质量)条件下,研究酶催化反应过程中不同HLB值的蔗糖脂肪酸酯和反应温度对1,3-甘油二酯生成量的影响。研究结果表明,选择HLB值为11的亲水性蔗糖脂肪酸酯,在添加量0.5%,反应温度60℃下反应24 h,1,3-甘油二酯生成量最高,为42.61%。  相似文献   

6.
利用Sn-1,3特异性脂肪酶对食品级鱼油中的二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)进行富集,而后利用偏甘油酯脂肪酶除去上述步骤产生的甘油二酯、甘油一酯,后处理得到具有天然属性的精制鱼油。采用单因素实验考察特异性脂肪酶富集EPA和DHA过程中脂肪酶用量、纯化水加入量、水解时间及水解温度对富集EPA和DHA的影响。运用气相色谱分析精制鱼油的脂肪酸组成。结果表明:特异性脂肪酶富集过程的最优工艺条件为在pH 6条件下固定化Sn-1,3特异性脂肪酶用量1%~15%、纯化水加入量1%~10%、水解时间2~6 h、水解温度30~70℃,富集后EPA和DHA总量为40%~60%,产品收率在48%~75%;精制鱼油含有21种主要脂肪酸,其中EPA和DHA含量最多。  相似文献   

7.
研究固定化脂肪酶TLIM催化单油酸甘油酯(glycerol monooleate,GMO)制备1,3-甘油二酯(sn-1,3-diacylglyerol,sn-1,3-DAG)。比较了游离脂肪酸(共轭亚油酸)和脂肪酸乙酯(共轭亚油酸乙酯)两种不同类型酰基供体、反应时间、底物物质的量比对酰基迁移和sn-1,3-DAG的影响。通过对实验结果的判定及分析得到最佳反应条件为采用20%(质量分数)脂肪酶TLIM、底物物质的量比(共轭亚油酸乙酯和GMO)3∶1、在50?℃的220 r/min水浴摇床中反应2 h,最后得到sn-1,3-DAG转化率为65%。本研究利用GMO而不是常规的甘油或者甘油三酯来制备sn-1,3-DAG,并比较了不同酰基供体对酰基迁移和sn-1,3-DAG转化率的影响,旨在为脂肪酶催化法制备功能性sn-1,3-DAG的研究提供一定参考。  相似文献   

8.
胰脂肪酶法测定食用油甘油三酯中脂肪酸的位置分布   总被引:5,自引:0,他引:5  
本实验采用sn-1,3位专一性脂肪酶(胰脂肪酶)对甘油三酯进行作用,专一水解位于sn-1、sn-3的酯键,将该两个位置上的脂肪酸游离出来,通过薄层层析分离得到游离脂肪酸和sn-2-甘油一酯,甲酯化作用后用气相色谱法对脂肪酸进行测定。用该方法对花生油、大豆油、玉米油、菜籽油、茶油进行了测定。结果表明,这几种油不饱和脂肪酸含量达到了80%,在sn-2位上分布更是超过了90%,而少量的饱和脂肪酸则主要是分布在sn-1,3位上。  相似文献   

9.
以无水奶油为脂肪酸来源,固定化脂肪酶TL IM为催化剂,无溶剂体系下催化3-甲硫基丙醇与无水奶油反应制备3-甲硫基丙酯。采用十七酸甲酯为内标,GC-FID监测反应过程中转化率的变化,并分析脂肪酶对不同碳链脂肪酸的选择性。结果显示:酶解前8h,脂肪酶对C4-C14脂肪酸选择性优势明显,随着反应的进行,对短链脂肪酸选择性逐渐变小,而对C16-C18脂肪酸选择性增加;当反应温度为50℃,脂肪酶添加量为5wt%,3-甲硫基丙醇与无水奶油的摩尔比3∶1,反应时间为8h时,产物中3-甲硫基丙酯的浓度分别为:丁酸3-甲硫基丙酯29.75mg/m L、己酸3-甲硫基丙酯15.32mg/m L、辛酸3-甲硫基丙酯7.22mg/m L、癸酸3-甲硫基丙酯21.32mg/m L、十二酸3-甲硫基丙酯26.64 mg/m L、十四酸3-甲硫基丙酯77.62mg/m L,C4-C14总转化率为71.16%。  相似文献   

10.
白地酶脂肪酶选择性酯化分离CLA异构体的研究   总被引:4,自引:1,他引:3  
本文研究共轭亚油酸异构体的分离方法。利用白地霉脂肪酶(Geotrichumcandidumlipase,GCL)催化合成正丁酯的方法,考察温度、体系水分、酶用量、反应时间、底物配比对脂肪酶催化酯化率和脂肪酸丁酯中c9t11含量的影响。结果表明,经过酯化的脂肪酸丁酯层中c9t11CLA含量达到79.85%,t10c12CLA含量为4.59%;含有13.75%的油酸;c9t11CLA占共轭亚油酸两种异构体总含量的94.56%。形成c9t11CLA正丁醇酯的选择性系数平均为17.80。脂肪酸与正丁醇比例对脂肪酸酯中c9t11CLA含量具有显著性影响,在选取的范围内水分含量、酶用量的影响不显著。要得到较高c9t11CLA含量的脂肪酸产物,反应因子应选择:水分为0.50%,脂肪酸与正丁醇用量比为2.00∶1.00,酶用量为100U/g。白地霉脂肪酶对催化c9t11共轭亚油酸与正丁醇的酯化反应具有较高的选择性,因此,脂肪酶选择性酯化分离CLA异构体的方法是可行的。  相似文献   

11.
酶法催化制备富含甘油二酯米糠油的研究   总被引:2,自引:0,他引:2  
以高酸值米糠油为原料,采用无溶剂体系酶法催化制备富含甘油二酯的米糠油.考察了脂肪酶种类及添加量,酯化剂种类,底物质量比,反应时间,反应温度对甘油二酯含量和游离脂肪酸残余量的影响.通过单因素试验和响应面试验,确定酶法催化酯化的最佳工艺条件为:固定化脂肪酶Lipozyme RM IM作为催化剂,油酸甘油一酯作为酯化剂,底物质量比0.25:1,反应温度56℃,反应时间5.75 h,脂肪酶添加量4.77%.在此条件下,产物中甘油二酯含量和游离脂肪酸残余量分别为27.61%和0.25%.  相似文献   

12.
BACKGROUND: The purpose of this study was to produce triacylglycerols (TAGs) enriched in pinolenic acid (PLA) at the sn‐2 position using the principle of acyl migration, from the pine nut oil containing PLA esterified exclusively at the sn‐3 position. RESULTS: Two types of lipase‐catalysed reactions, i.e. redistribution and reesterification of fatty acids, were successively performed using seven commercially available lipases as biocatalysts. Of the lipases tested, Novozym 435 and Lipozyme TL IM were effective biocatalysts for positioning PLA at the sn‐2 location. These biocatalysts were selected for further evaluation of the effects of reaction parameters, such as temperature and water content on the migration of PLA residues to the sn‐2 position and TAG content. For both lipases, a significant decrease in TAG content was observed after the lipase‐catalysed redistribution of fatty acids for both lipases. The reduced TAG content could be enhanced up to approx. 92%, through lipase‐catalysed re‐esterification of the hydrolysed fatty acids under vacuum. CONCLUSION: TAG enriched in PLA at the sn‐2 position was synthesised from pine nut oil via lipase‐catalysed redistribution and re‐esterification of fatty acid residues using Lipozyme TL IM and Novozym 435 as biocatalysts. Copyright © 2011 Society of Chemical Industry  相似文献   

13.
Human milk fat substitute (HMFS) was prepared by Lipozyme RM IM-catalyzed acidolysis of lard and fatty acids obtained from palm kernel oil, tea seed oil and soybean oil, in a solvent-free system. The effects of substrate mass ratio, Lipozyme RM IM load and reaction time on the total fatty acids composition and sn-2 fatty acids composition were investigated. To optimize the reaction conditions, an orthogonal design was selected with three levels and three factors. Substrate mass ratio, Lipozyme RM IM load and reaction time were the factors employed. Under the given reaction temperature of 60 °C, the optimal reaction conditions were, 1/2 mass ratio of lard/fatty acids blend, 7% Lipozyme RM IM load and 1-h reaction time. By the “deducting score” principle, the produced HMFS in comparison with the reported HMFS possessed highest degree of similarity with local HMF from Guangzhou mothers. The results showed that it was possible to produce HMFS through the scale-up enzymatic acidolysis.  相似文献   

14.
Diacylglycerols (DAG) were enzymatically synthesized by lipase-catalyzed esterification of glycerol with fatty acids from corn oil deodorizer distillate (CrODD). Effects of reaction parameters such as reaction time, temperature, enzyme type, enzyme load, substrate mole ratio, and water content, as well as the effect of molecular sieves as a water adsorbent were investigated. Rhizomucor miehei lipase (Lipozyme RM IM) was found to be most effective among the lipases screened. The following conditions yielded 70.0% (w/w) DAG: 5 h reaction time, 65°C reaction temperature, 10% (w/w) Lipozyme RM IM, 2.5:1 fatty acid to glycerol molar ratio, and 30% (w/w) molecular sieves. DAG synthesis of 12.4% (w/w) was still observed at 10% (w/w) water content. 84.2% (w/w) of DAG was obtained after purification. The DAG oil comprised predominantly of 1-oleoyl-3-linoleoyl-glycerol (28.5%), 1,3-diolein (22.7%), 1-oleoyl-2-linoleoyl-glycerol (17.9%), and 1,2-diolein (10.9%). Fatty acid profile was similar to that of refined, bleached and deodorised (RBD) corn oil. The ratio of 1,3- to 1,2-positional isomers of DAG was at 1.82:1.  相似文献   

15.
Structured triacylglycerols, containing medium chain fatty acids, were produced by acidolysis of virgin olive oil with caprylic or capric acid, at a molar ratio of olive oil:fatty acid of 1:2, at 45 °C for 24 h, in solvent-free media or in n-hexane, catalysed by Thermomyces lanuginosa (Lipozyme TL IM), Rhizomucor miehei (Lipozyme RM IM) and Candida antarctica (Novozym 435) immobilised lipases. Incorporations were always greater for capric than for caprylic acid. For both acids, higher incorporations were always attained in solvent-free media: the highest caprylic acid incorporations were obtained with Novozym 435 (25.5 mol%) and Lipozyme RM IM (25.7 mol%), while similar capric acid incorporations were obtained with all biocatalysts (27.1–30.4 mol%).  相似文献   

16.
Oleyl oleate can be considered a synthetic analogue of jojoba oil. This one has been the main natural source of wax esters for commercial applications since the global ban on whale hunting. Lipase catalyzed production of this ester was carried out using oleic acid and oleyl alcohol in a solvent-free system. Lipase from Rhizopus sp. CBMAI 1127 was used as the biocatalyst and commercial enzyme Lipozyme TL IM? was used to compare results. The acid/alcohol molar ratio showed significant effects for both lipases and the amount of enzyme had a significant effect just for Lipozyme TL IM?. The rate of the esterification reaction using lipase from Rhizopus sp. CBMAI 1127 was very similar to that obtained with commercial lipase. The present study also evaluated antimicrobial and emulsifying properties of this ester. Emulsifying capacity of the synthesized oleyl oleate was lower than Tween 80 and sodium dodecyl sulfate, and no antimicrobial activity was observed.  相似文献   

17.
为更准确地反映脂肪酶在催化酯化反应过程中的变化规律,设计、研制了将脂肪酶催化底物所产生的电子转移过程转换为电流输出的电化学生物传感器。分别以Novozym 435和Lipozyme TLIM作为生物元件,采集65℃下共轭亚油酸与甘油酯化反应过程的电流变化,用液相色谱仪测定反应过程中底物的含量,验证电流变化过程与酯化反应过程的吻合程度。通过实验证明相对误差为4.7%。证明了通过检测反应过程的电流变化可以判断酶催化底物反应的程度,为实现计算机连续在线检测控制反应过程提供理论基础。  相似文献   

18.
BACKGROUND: Structured lipids containing medium‐chain fatty acids have interesting applications as reduced‐calorie fats; moreover, conjugated linoleic acid (CLA) isomers have shown interesting biological properties. The aim of this study was to synthesize triacylglycerols (TAGs) containing capric acid in the sn‐1‐ and sn‐3‐ positions and CLA isomers in the sn‐2‐ position, using different commercial available lipases. RESULTS: The homogeneous CLA‐TAGs (Tri‐CLA) were chemically synthesized starting from glycerol and CLA isomers, 9‐cis,11‐trans and 10‐trans,12‐cis CLA. The acidolysis reactions of Tri‐CLA with capric acid were carried out at 55 °C for different times in hexane; after 96 h the acidolysis average yield was 65%. The best capric acid incorporation in total TAGs was obtained after 96 h with Lipozyme IM (56.6%). The results of structural analysis carried out on the obtained TAGs showed that both Novozyme 435 and anhydrous Lipozyme IM gave the best incorporation of capric acid in sn‐1(3)‐ positions (61.8%). However, anhydrous Lipozyme IM gave also the highest CLA percent content in sn‐2‐ position (73.2%). CONCLUSION: Anhydrous Lipozyme IM appears to be the more effective enzyme in acidolysis reactions to obtain structured TAGs containing CLA isomers in the central position and capric acid at external positions. Copyright © 2009 Society of Chemical Industry  相似文献   

19.
Structured lipids (SL) were synthesized by the acidolysis of borage oil with caprylic acid using lipases. Six commercial lipases from different sources and a novel lipase from Pichia lynferdii NRRL Y-7723 were screened for their acidolysis activities and Lipozyme RM IM and NRRL Y-7723 lipase were selected to synthesize symmetrical SL since recently NRRL Y-7723 lipase was identified as a novel cold-active lipase. Both lipases showed 1,3-regiospecifity toward the glycerol backbone of borage oil. The effects of enzyme loading and temperature on caprylic acid incorporation into the borage oil were investigated. For Lipozyme RM IM and NRRL Y-7723 lipase, the incorporation of caprylic acid increased as enzyme loading increased up to 4% of total weight of the substrate, but significant increases were not observed when enzyme loading was further increased. The activity of NRRL Y-7723 lipase was higher than that of Lipozyme RM IM in the temperature range between 10 and 20 °C.  相似文献   

20.
Lipase-catalyzed modification of lard to produce human milk fat substitutes   总被引:2,自引:0,他引:2  
The objective of the present work was to modify lard into human milk fat substitutes (HMFS) by Lipozyme RM IM-catalyzed acidolysis. Lard and soybean fatty acids were esterified in a solvent-free system. The reaction substrates for HMFS production were specially chosen to mimic human milk fats. Factors such as temperature, time, water content, enzyme load, substrate ratio, and enzyme reusability were investigated. The relationships between initial incorporation rate (Inc/h) and temperature (T, K) were set up, based on the Arrhenius law for both linoleic and for linolenic acids. Scale-up trials were carried out to confirm the feasibility of enzymatic modification for the production of HMFS. The characteristics of the product, produced in the scale-up acidolysis under selected conditions (temperature 61 °C, water content 3.5%, lard:fatty acids 1/2.4 (mol/mol), Lipozyme RM IM load 13.7%, and time 1.0 h), were similar to the fat in Chinese mothers' milk. The results showed that it was possible to produce human milk fat substitutes from lard through enzymatic acidolysis with soybean fatty acids.  相似文献   

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