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研究了无溶剂体系固定化1,3-特异性脂肪酶Lipozyme RM IM催化棕榈酸和山茶油酸解反应中,棕榈酸在产物甘油三酯中Sn-2位的相对含量分布以及酰基转移规律。考察了酶用量、底物摩尔比、酶水分活度、反应温度和反应时间对酸解反应的影响。结果表明:酶水分活度、反应温度和反应时间对棕榈酸在产物甘油三酯中的含量影响不大,对酰基转移影响较大;在酶水分活度0.550,反应温度60℃,反应时间1 h的反应条件下,酰基转移的程度最小;底物摩尔比和酶用量对酰基转移的程度影响不大。 相似文献
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肖乾煌徐雨茜熊华胡蒋宁朱雪梅张钰岩 《中国油脂》2020,45(3):62-67
以三棕榈酸甘油酯(PPP)和油茶籽油游离脂肪酸(FFA)为底物制备1,3-二油酸-2-棕榈酸甘油酯(OPO)结构脂为反应模型,以专一性脂酶Lipozyme RM IM为催化剂,研究不同有机溶剂(正己烷、丙酮、叔丁醇)、不同反应时间(0、2、4、6、8 h)、不同水分活度(a_w)(0.11、0.53、0.97)对酰基迁移的影响。结果表明:在3种溶剂中,丙酮的反应环境下酰基迁移发生率最低且油酸的键入率最高;在不同溶剂、不同水分活度的条件下,均在a_w为0.53时sn-2位棕榈酸和sn-1,3位油酸的含量较高,说明a_w影响脂肪酶的1,3位置选择性强弱决定于a_w的高低。鉴于结构脂制备过程中的绿色环保安全角度,可以采用无溶剂体系但是应较好地控制反应体系的a_w以抑制酰基迁移。 相似文献
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《食品科技》2016,(12)
以脂肪酶Lipozyme TLIM催化共轭亚油酸(CLA)和松籽油制备sn-2位含有CLA和松籽油酸(PLA)的结构脂,考察体系水分活度对CLA键入率和酰基迁移的影响。在水分活度0.22~0.80的范围内,松籽油中CLA的键入量随CLA水分活度的增加而增加,而酰基迁移也随着水分活度增加而增加。但是通过研究酰基迁移与CLA键入量的关系,发现当酰基迁移程度一定时(如0.6)水分活度越高总CLA键入量越高。因此,若要抑制酰基迁移则增大水分活度并相应的缩短反应时间,因为高水分活度体系中脂酶催化的反应速率加快;反之,若要促进酰基迁移则选用水分活度低的体系,并相应的延长反应时间,反应时间越长,体系越接近动力学平衡,Sn-2脂肪酸几乎等于总脂肪酸。本实验在反应温度60℃、加酶量10%、松籽油与CLA质量比为4:1、水分活度0.65的条件下反应18 h制备结构脂,在所得结构脂中CLA的含量为10.10%,PLA的含量为15.17%;甘油三酯中sn-2位脂肪酸组成中CLA达到7.41%,PLA含量为9.29%。 相似文献
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在Lipozyme RM IM脂肪酶的催化作用下,将分提后的棕榈硬脂与油酸和亚油酸反应,通过酶法酸解合成富含1-油酸-2-棕榈酸-3-亚油酸甘油三酯(OPL)的结构脂,通过单因素实验对酶法合成反应条件进行了优化。结果表明,合成OPL结构脂的最优反应条件为:棕榈硬脂、油酸、亚油酸摩尔比1∶7∶7,酶添加量8%,反应温度60℃,反应时间6 h。在最优条件下,进行50倍放大实验,合成产物中OPL和sn-2位棕榈酸的含量分别为48.37%和84.70%。 相似文献
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以Lipozyme TLIM催化茶油和共轭亚油酸乙酯制备共轭亚油酸(conjugated linoleic acid,CLA)结构脂,并调控酰基迁移反应以制备Sn-2位含CLA的结构脂。通过响应面法研究反应温度、水分活度、反应时间和底物物质的量比对总CLA键入量和酰基迁移的影响,并优化反应条件。本实验得到的结构脂中含有36.97%的总CLA,其中12.54%的CLA分布在Sn-2位,所得总CLA及Sn-2位的CLA键入量均高于文献报道。 相似文献
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以巴沙鲶鱼油为原料、高油酸葵花籽油来源的游离脂肪酸为酰基供体,采用Lipozyme RM IM脂肪酶为催化剂催化酸解反应制备富含OPO的人乳替代脂。并采用液质联用对巴沙鲶鱼油、酸解巴沙鲶鱼油、市售Betapol~(TM)的sn-OPO含量进行分析。结果表明,最佳制备条件为:底物摩尔比1∶6,酶用量12%,反应温度60℃,水分含量3.5%(基于酶质量),反应时间3 h。在最佳条件下,酸解产物中sn-2棕榈酸分布和sn-1,3油酸含量分别为73.18%和71.11%。酸解产物中sn-OPO含量从23.35%提高到34.28%,高于市售Betapol~(TM)的33.24%。 相似文献
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《Food chemistry》2005,92(1):101-107
Acyl migration in the glycerol backbone often leads to the increase of by-products in the enzymatic production of specific structured lipids. Acyl migration is a thermodynamic process and is very difficult to stop fully in actual reactions. The objective of this study was to investigate the feasibility of suppressing acyl migration by a programmed change of reaction temperature without loss of reaction yield. The model reactions were the acidolysis of tripalmitin with conjugated linoleic acid (CLA) or with caprylic acid (CA) targeted for human milk fat substitutes. Acyl migration was considerably inhibited in the temperature-programmed acidolysis of PPP with CLA or CA, with only slight reduction of acyl incorporation, the reaction leading to the required products. Acyl migration was reduced by 29% (35 h) and 45% (48 h), respectively, in the acidolysis of PPP with CLA under solvent and solvent-free systems, in comparison with 37% (35 h) and 61% (48 h), respectively, for the acidolysis of PPP and CA. Acyl migration in the acidolysis of PPP with CA was, in general, lower than the acidolysis of PPP with CLA in both systems. Temperature programming was more prominent in solvent-free systems for the reduction of acyl migration. Acyl incorporation was not significantly affected by temperature programming. The study suggests that it is feasible to reduce acyl migration by programmed change of acidolysis temperature without significant loss of reaction yield. 相似文献
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The acyl incorporation and migration of linoleic and conjugated linoleic acids in enzymatic acidolysis were compared in a solvent-free system. Two systems were used in the Lipozyme RM IM-catalyzed acidolysis at 60C temperature and 5% by weight enzyme load (based on substrates). One included tristearin (SSS) and linoleic (L) or conjugated linoleic (cL) acids (1:6, mol/mol). The other was between tristearin and the mixture of linoleic and conjugated linoleic acids (1:3:3, mol/mol/mol). Acyl incorporation and migration together with triacylglycerol composition of the products were monitored with gas chromatography, pancreatic lipase hydrolysis, and high performance liquid chromatography. Both acyl incorporation and migration of linoleic acid were faster than those of conjugated linoleic acid. At 5 h reaction, there were 13.0% LLL, 46.5% LSL, 27.7% LSS, and 5.6% SSS in the product for a system between tristearin and linoleic acid; whereas there were 2.4% cLcLcL, 10.4% cLScL, 50.9% cLSS, and 36.2% SSS in the product for a system between tristearin and conjugated linoleic acid. The results suggest that linoleic acid was more reactive than conjugated linoleic acid in the enzymatic acidolysis probably because of the rigid structure of the latter. 相似文献
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酶催化酸解生产结构脂质的研究进展 总被引:1,自引:0,他引:1
酸解是酯交换的一种,用该法制备结构脂质的主要原料为油脂和脂肪酸,阐述了酶催化酸解制备结构脂质所需的几种重要的脂肪酸,分析了所采用的脂肪酶及酶反应器的特点,指出了当前工业化生产结构脂质的研究重点。 相似文献
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DEQUAN ZHOU XUEBING XU HUILING MU CARL-ERIK HØY JENS ADLER-NISSEN 《Journal of Food Lipids》2000,7(4):263-274
Structured lipids containing eicosapentaenoic and docosahexaenoic acids were manufactured in a batch reactor by lipase-catalyzed acidolysis of fish oil with caprylic acid. The following free lipases (Lipase AP, Aspergillus niger ; Lipase P, Pseudomonus sp. ; Lipase AY, Candida rugosa ; Lipase AK, Pseudomonas fluoresescens ; Lipase F, Rhizopus oryzae ; Lipase D, Rhizopus delemar ) were screened under selected reaction conditions. The conditions were enzyme load 5%, substrate mole ratio 1:6 (fish oil: caprylic acid), and reaction temperature of 50C. Lipase AK had the highest activity and was suitable for production of structured lipids from fish oil. The optimal mole substrate ratio of fish oil to caprylic acid for Lipase AK was 1:6 to 1:8. The time course of the reaction at different enzyme loads demonstrated that 40% incorporation of caprylic acid could be obtained for Lipase AK in 5 h with 10% enzyme load. Addition of water had little effect on the activity of the lipase. Lipase AK and Lipozyme IM were further compared under the same conditions, in which Lipase AK had a slightly higher incorporation of caprylic acid, similar acyl migration of caprylic acid from sn-1,3 positions to the sn-2 position, and a slightly lower selectivity towards docosahexaenoic acid. 相似文献
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Biqian Chen Hong Zhang Ling-Zhi Cheong Tianwei Tan Xuebing Xu 《Food and Bioprocess Technology》2012,5(2):541-547
Enzymatic production of ABA-type structured lipids (SLs) containing marine-derived long-chain polyunsaturated fatty acid (n-3
PUFA) and medium-chain fatty acids was investigated. Response surface methodology was applied to optimize the reaction system
and evaluate the effects of reaction factors and different acyl donors namely n-3 PUFA and n-3 PUFA ethyl esters (n-3 PUFA-EE).
Well-fitting models were obtained by multiple regressions with backward elimination. For both n-3 PUFA and n-3 PUFA-EE systems,
both reaction time and enzyme load had significant (P < 0.05) positive effects on incorporation and acyl migration rate. Water content were found to have significant (P < 0.05) negative effects on incorporation but positive effects on acyl migration in the n-3 PUFA-EE system. Although there
were no significant difference in terms of incorporation rate, n-3 PUFA were found to produce five times higher acyl migration
rate than n-3 PUFA-EE. The optimal reaction conditions to produce high yield of ABA-type SLs of 49.6% with low acyl migration
rate of 2.6% were as follows: n-3 PUFA-EE as acyl donors; enzyme load, 6 wt.%; reaction time, 6 h; and water content, 3 wt.%.
Thus, n-3 PUFA-EE was found to be a suitable acyl donor to produce high yield of ABA-type SLs with low acyl migration rate. 相似文献
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In the present study, sunflower oil was modified with a palmitic–stearic acids blend by means of an immobilized sn-1,3 specific lipase (Lipozyme RM IM) to produce structured lipids. Products were analyzed to determine fatty acid incorporation (FM) into triacylglycerol structure and to quantify by-products as monoglycerides (MG) and diglycerides (DG). The effects of the reaction conditions (temperature, time, incorporated water) on enzymatic acidolysis were studied. Nonlinear regression methods were employed to fit experimental data with kinetic models proposed in the literature. The disappearance of reactant fatty acids (RF) over time was successfully modeled by a Ping-Pong Bi-Bi mechanism. FM was also represented with a lumped parameter model of the enzymatic mechanism. Maximum RF disappearance and FM onto sunflower oil glycerides increased with increasing reaction temperature. MG and DG concentrations in water-free systems were stabilized in low levels, while the incorporation of water to the reaction mixture produced a considerable increase in DG formation principally. Kinetic and equilibrium parameters showed temperature dependencies. 相似文献
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结构脂质是一类将具有特殊生理功能的脂肪酸结合到甘油三酯骨架上特定位置重新组合生成的新型脂质。酶法催化合成结构脂质具有反应条件温和,能耗低,分离纯化工艺简单,以及可以合成特定酰基位置上的功能性脂肪酸而受到重视。工业上随着酯酶使用次数的增加,酯酶催化活力显著下降,导致目标结构脂质产量降低。本文综述了近年来国内外关于酯酶催化合成结构脂质酯酶结构改变、活性变化和催化活性下降机理,酶活性下降主要是因为分子间强相互作用或弱相互作用破坏酶催化活性中心,本研究可为解决酶法合成结构脂质面临的酯酶活力降低的技术瓶颈提供参考。 相似文献