酶催化亚麻籽油甘油解制备富含α-亚麻酸的甘油二酯的研究

在无溶剂体系中,以亚麻籽油和甘油为反应底物,Lipozyme435为催化剂,制备富含α-亚麻酸的甘油二酯,采用单因素实验与响应面分析法考察了制备过程中底物摩尔比、反应时间、加酶量和反应温度对甘油二酯得率的影响。结果表明,反应的最佳条件为底物摩尔比(亚麻籽油∶甘油)=5∶3,加酶量8.8wt%,反应温度为58.3℃,反应时间为9.1h。在此反应条件下反应所得产物中甘油二酯含量约达50.21%,纯化后的甘油二酯的理论纯度可达60.12%,α-亚麻酸的含量达46.41%。     

α-亚麻酸芦丁酯的酶法合成工艺研究

以脂肪酶Novozym435为生物催化剂,建立了新型功能脂质α-亚麻酸芦丁酯的酶促合成工艺,并通过响应面方法系统考察了反应工艺参数对酯化率的影响。得到的最佳合成工艺参数为：反应溶剂为丙酮,脂肪酶Novozym435的添加量为17.9mg/mL, 芦丁的底物浓度为17.3mmol/L, 芦丁与α-亚麻酸的摩尔比为1：4.5,反应时间60h,酯化率高达92.6%,经过提纯后产物纯度可达到95.0%。     

α-亚麻酸与γ-亚麻酸

α－亚麻酸与γ－亚麻酸是两种具有重要生理功能的不饱和脂肪酸,也是当前热点研究和开发的对象,在比较的基础上综合阐述了α－亚麻酸与γ－亚麻酸的结构、生理功能及主要生物资源。     

无溶剂直接酯化法合成α-亚麻酸植物甾醇酯工艺研究

研究了植物甾醇与α-亚麻酸无溶剂直接酯化法合成α-亚麻酸植物甾醇酯的最佳工艺条件.通过单因素试验研究了α-亚麻酸和植物甾醇不同质量比、催化剂添加量、反应时间及反应温度对α-亚麻酸植物甾醇酯酯化率的影响.通过正交试验对α-亚麻酸植物甾醇酯合成工艺进行优化,最终得到优化工艺条件为:即真空度为0.03～0.04 MPa,α-亚麻酸与植物甾醇的质量比4:1,催化剂量为2.5%,反应时间为8 h,反应温度140℃,在此条件下,α-亚麻酸植物甾醇酯的酯化率为(98.88±0.984)%.因此,通过本论文的研究得到了一种绿色、安全、高效的α-亚麻酸植物甾醇酯合成工艺.     

亚麻籽油中α-亚麻酸降血脂功能研究

研究亚麻籽油中α-亚麻酸对实验性高血脂小白鼠的预防和治疗作用。采用β-环糊精包合法从亚麻籽油中分离高纯度α-亚麻酸,把50只SPF级KM雌性小鼠分为空白实验组、高脂模型组和3个实验剂量组,对其进行α-亚麻酸降血脂实验研究。结果表明,亚麻籽油中α-亚麻酸能有效降低高血脂小白鼠血清中的总胆固醇水平、甘油三酯和低密度脂蛋白胆固醇水平,提高高密度脂蛋白胆固醇水平,能使血浆致动脉硬化指数降低,对小白鼠的高血脂症和动脉硬化有明显的抑制作用。利用β-环糊精包合法从亚麻籽油中分离纯化的α-亚麻酸具有显著的预防和治疗高脂血症的作用。     

脂肪酶催化合成α-亚麻酸植物甾醇酯的工艺研究

酶法催化合成甾醇酯工艺是当前的研究重点之一。本文首次研究了脂肪酶催化合成α-亚麻酸植物甾醇酯,重点通过单因素和正交实验考察了多种脂肪酶、有机溶剂及其添加量、物料比、反应温度、反应时间等多种因素对酯化率的影响,并采用薄层色谱法和红外光谱法对产品进行了分析鉴定。研究结果表明,选取Novozyme 435和异辛烷作为合成反应的催化剂和溶剂,添加量分别为5%和1∶1.6（溶剂体积?底物质量）,在α-亚麻酸和甾醇摩尔比为3∶1、反应温度为55℃条件下反应24h时,酯化率达到40.65%,产品经精制后α-亚麻酸植物甾醇酯纯度能达到85%以上。通过本文的研究,成功得到了一种酶法催化合成α-亚麻酸植物甾醇酯的工艺。      

分子蒸馏纯化亚麻籽油中α-亚麻酸的研究

亚麻籽油经甲酯化后,采用分子蒸馏法对其中α-亚麻酸进行分离纯化,用α-亚麻酸的质量分数、提取率作为衡量纯化效果的指标。经单因素实验确定蒸馏温度、刮膜转速、预热温度和进料速度的操作范围,并利用响应曲面法的Box-Behnken实验设计,得到提纯α-亚麻酸的优化工艺条件:蒸馏温度91℃、刮膜转速250r/min、预热温度60℃、进料速度57mL/h,在此工艺条件下,α-亚麻酸质量分数从53.36%提高至80.27%,提取率为76.20%。      

α-亚麻酸甾醇酯检测技术研究

植物甾醇酯是一种新型功能性食品添加剂,具有良好亲脂性和降胆固醇效果。采用薄层色谱法、紫外分析法、红外分析法和气相色谱法相结合的方法对α-亚麻酸甾醇酯产品进行分析检测,为α-亚麻酸甾醇酯和甾醇的分离、定性和定量提供参考。     

脂肪酶催化大豆色拉油甘油解合成单甘酯

研究了间歇反应条件下脂肪酶催化大豆色拉油甘油解制备单甘酯的过程,对三种商业酶和自制固定化脂肪酶进行了筛选,并对影响甘油解过程的溶剂效应和酶量因素进行了研究。采用了响应面分析方法对甘油解反应进行优化,以单甘酯百分含量为响应值,对底物摩尔比、初始含水量、温度这三个因素的重要性做了适当评价,并给出了拟和良好、回归显著、可靠性较好的经验性模型方程。优化条件为:反应温度46℃,初始水质量分数4%(相对于大豆色拉油),底物甘油与豆油摩尔比为3.7∶1,固定化酶用量质量分数5%(相对于大豆色拉油),反应时间30h,单甘酯最高转化率为74.04%。     

响应面优化酶催化米糠油甘油解制备甘油二酯

利用响应面(RSM)对叔丁醇溶剂体系中的脂肪酶Novozym 435催化米糠油甘油解反应合成甘油二酯(DAG)的反应条件进行了优化。在单因素实验基础上选取反应温度、反应时间、酶添加量(酶和米糠油质量比)、底物质量比(米糠油:甘油)等4个因素作为自变量,以DAG的产率为响应值,进行5水平4因素中心组合旋转设计(CCRD)优化,确定了影响DAG合成的关键因素以及最佳反应条件。分析结果表明,在各影响因素中,底物质量比对DAG的产率影响最大。综合考虑优化和节约后,利用模型计算DAG合成的最佳条件:反应温度60℃,反应时间10.5h,加酶量10.66%,底物质量比16,在此条件下DAG产率是53.08%。      

Optimal conditions for the production of monoacylglycerol from crude palm oil by an enzymatic glycerolysis reaction and recovery of carotenoids from the reaction product

Monoacylglycerol (MAG) was produced from crude palm oil (CPO) by the enzymatic glycerolysis reaction in organic solvents. The optimal conditions for MAG production from CPO were: the use of a mixture of tert‐butanol and hexane (1:1) as the organic solvents; an immobilised lipase of 40%; a molar ratio of glycerol to CPO of 8:1 with 4% of water content in the glycerol; and an initial CPO concentration of 10%. A maximum yield of 74.3% MAG was obtained with an initial production rate of 42.3 mg MAG mL^?1 h^?1. By converting CPO to the more polar MAG, the efficiency of recovery of carotenoids by adsorption column chromatography was improved up to 75.7% from 55.1% when using unconverted CPO. This study provides information that will be useful for developing an efficient and cheaper industrialised process for the production of MAG from CPO and recovery of carotenoids from the reaction product.     

Monoacylglycerol Production from Butteroil by Glycerolysis with a Gel-Entrapped Microbial Lipase in Microaqueous Media

Reaction parameters were optimized to support polyethyleneglycol-based and polypropyleneglycol-based gel-entrapped lipase-mediated glycerolysis of butteroil to yield monoacylglycerol. Single liquid-phase reactive mixtures contained 25% (w/w) butteroil dissolved in t-butanol, to which glycerol and water was added. Optimum reaction conditions were 35–40 °C, and 5–10 mg enzyme reagent and 0.10g glycerol/mL substrate solution. Optimum acyl group:glycerol molar ratio was about 0.64. The optimum water content was dependent on glycerol content and was about 6% (w/w) of the glycerol at 0.10g glycerol/mL substrate solution. The gel-entrapped lipases had half-lives of about 35–46 cycles of 72 hr each.     

响应面法优化葵花籽油中蜡质脱除工艺

以高油酸葵花籽原油为原料,采用冷冻脱蜡工艺,通过单因素试验和响应面试验研究了养晶时间、养晶温度、硅藻土添加量、搅拌速率对脱蜡效果的影响,并对脱蜡前后葵花籽油的脂肪酸组成进行了检测。结果表明：最优脱蜡工艺条件为养晶时间16 h、养晶温度11 ℃、硅藻土添加量1.5%、搅拌速率8 r/min,在此条件下脱蜡葵花籽油中蜡质含量为22.50 mg/kg;脱蜡前后葵花籽油脂肪酸组成无显著变化,说明脱蜡不会影响葵花籽油的脂肪酸组成。     

Lipase-catalyzed production of solid fat stock from fractionated rice bran oil,palm stearin,and conjugated linoleic acid by response surface methodology

Solid fat stock was produced from the fractionated rice bran oil (solid phase, S-RBO) and palm stearin (PS) through lipase-catalyzed reaction, in which conjugated linoleic acid (CLA) was intentionally incorporated. For optimizing the reaction, response surface methodology (RSM) was employed with four reaction variables such as water activity, reaction temperature, reaction time, and mole ratio of S-RBO to PS. The predictive model was adequate due to no significant lack of fit and satisfactory level of coefficient of determination (R² = 0.95). The melting point of solid fat stock was affected by reaction time and substrate mole ratio, whereas water activity and reaction temperature had no significant effect. Based on ridge analysis, the combination of A_w (X₁; 0.32), reaction temperature (X₂; 65.3 °C), reaction time (X₃; 28.9 h), and substrate mole ratio (X₄; 1:1.1) was optimized for producing solid fat stock with target melting point of 43.8 °C. The solid fat stock (SFS) contained 39.9% palmitic, 31.3% oleic, 13.2% linoleic acid, and 10.9% CLA isomers. Solid fat contents were 23.4, 10.9, and 2.5% at 20, 30, and 40 °C, respectively. These results suggested that RSM can be used to optimize the lipase-catalyzed production of a solid fat stock.     

固体超强酸催化大豆油和大豆油脂肪酸酯化与酯交换制备单甘酯的研究

采用固体超强酸催化大豆油和大豆油脂肪酸与甘油酯化和酯交换制备单甘酯,通过二级分子蒸馏纯化单甘酯。通过响应面优化得到的最佳条件为：大豆油30.0 g,大豆油脂肪酸20.0 g,反应温度200℃,固体超强酸催化剂添加量0.26%（占大豆油和大豆油脂肪酸质量）,甘油添加量12.66 g和反应时间4.81 h。在最佳条件下,反应得到的甘油酯混合物中,单甘酯含量达到69.82%。甘油酯混合物在Ⅰ级135℃分子蒸馏除去游离脂肪酸和甘油,在Ⅱ级185℃分子蒸馏蒸出单甘酯,得到产品中单甘酯含量为96.54%。     

酶法合成咖啡酸叶黄素酯的研究

以叶黄素和咖啡酸为原料,在脂肪酶Novo435的催化下,首次合成了咖啡酸叶黄素酯。研究了脂肪酶催化叶黄素与咖啡酸合成咖啡酸叶黄素酯的影响因素,考察了酶量、溶剂、体系水分、温度、时间等因素对酯化反应的影响。结果表明,适宜的工艺条件是:酶量10mg/mL,溶剂为氯仿,水含量10mg/g,温度40℃,反应时间24h,在上述条件下咖啡酸转化率可达88%。采用IR对目标产物的结构进行了表征。     

响应面法优化固相化脂酶Lipozyme TL IM催化菜籽油水解过程

采用响应面法对固相化脂酶Lipozyme TL IM水解菜籽油过程中影响水解率的因素进行优化.采用Plackett - Burman法对5个因素进行了筛选,结果表明水油质量比值、反应温度和反应时间3个因素对水解率影响显著.利用最陡爬坡试验、Box - Behnken设计结合响应面分析得到各因素最佳水平为:水油质量比值0.617,反应温度60.1℃,反应时间18.23 h,在此条件下水解率预测值可达到79.35％.实测结果与响应面拟合所得方程的预测值符合良好.     

Linseed oil stabilisation with pure natural phenolic compounds

Linseed has been used for a very long time in human and animal nutrition. Currently, there is an increasing interest in linseed oil because of its particularly high content in α-linolenic acid (ALA), an omega-3 fatty acid (FA). Unfortunately, ALA turns also the oil extremely sensitive to oxidation. This study aimed at assessing four pure representative phenolic compounds, myricetin (flavonol), (+)-catechin (flavanol), genistein (isoflavone), and caffeic acid (hydroxycinnamic acid) at a concentration of 555 μmol/kg as antioxidants in refined linseed oil (RLO). Their protective effect was assessed by monitoring the hydroperoxide formation, the FA profile and the residual antioxidant concentration in RLO, along its storage at 60 °C according to the Schaal oven test procedure. Caffeic acid, (+)-catechin and myricetin were found to be more efficient than butylated hydroxyanisole (BHA), a synthetic antioxidant. Interestingly, myricetin strongly reduced ALA oxidation. These results confirm that the chemical structure of the phenolic compounds plays a major role in their antioxidant properties.