共查询到19条相似文献,搜索用时 250 毫秒
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《中国油料作物学报》2015,(6)
为利用大豆粉末人工合成多不饱和脂肪酸(PUFA),在正己烷体系中,以脂肪酶Lipozyme RM IM催化花生四烯酸乙酯(92.6%)与大豆粉末磷脂进行酯交换反应,制备富含花生四烯酸(ARA)的结构磷脂。系统考察了酶促反应温度、反应时间、酶添加量及底物摩尔比对花生四烯酸结构磷脂中ARA结合率的影响。在单因素实验的基础上,通过响应面方法对合成富含ARA结构磷脂的工艺参数加以优化。经分析验证得到最佳工艺参数为:反应温度55.6℃,反应时间25.1h,酶添加量15.3%,底物摩尔比1∶10.1。在此最优条件下,富含ARA结构磷脂的产率为13.26%,ARA的结合率达15.42%。此外,通过质谱鉴定了合成产物中的卵磷脂(PC)分子种类。 相似文献
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儿茶素组成和理化条件对茶黄素酶催化合成的影响 总被引:1,自引:0,他引:1
利用梨果实多酚氧化酶,在单因素试验基础上,设计正交试验,进行酶性合成茶黄素,研究儿茶素组成和理化条件对茶黄素合成的影响,以确定最佳反应条件。结果表明,以儿茶素混合物C(EGC>200mg/g,EGCG>200mg/g,儿茶素总量>500mg/g)为材料,茶黄素酶促合成的最佳条件为:反应体系的最佳pH值为5.5,温度为30℃,底物浓度为5mg/ml,酶添加量为75ml/1000mg,最佳反应时间40min。pH值和儿茶素浓度是反应体系中两个重要的影响因子(P<0.05)。 相似文献
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MRPs作为天然抗褐变剂,可抑制引起果蔬酶促褐变的酪氨酸酶的酶活。为进一步优化美拉德反应以制备酪氨酸酶活性抑制组分,本研究采用响应面法对MRPs制备工艺进行研究。在单因素实验基础上,确定美拉德反应初始pH、反应温度、反应时间、底物浓度比(糖∶氨基酸)4个因素,设计4因素5水平的二次回归中心组合试验。经响应面法分析,为方便实际操作,确定最佳工艺条件为:初始pH为2.94,反应时间为1.9 h,反应温度为110.09℃,底物浓度比(糖∶氨基酸)为0.57。经实验验证,得出结果与理论值相对误差较小,故采用二次回归中心组合设计得到的最优MRPs制备条件参数准确可靠。 相似文献
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响应面法优化大豆油下脚料制备生物柴油工艺的研究 总被引:1,自引:0,他引:1
随着全球性能源的日益短缺与环境的逐渐恶化,生物柴油作为一种无毒、可生物降解和再生的替代燃料正受到越来越多的关注.研究了利用大豆油下脚料(油脚、皂脚混合物)制取生物柴油的工艺过程.先用乙醚室温下萃取下脚料,料液比1∶2(g∶mL),萃取时间2 h.离心后分为3层,上层有机相再经丙酮萃取分离出磷脂和中性油,磷脂作为高附加值副产品回收再利用以降低生物柴油的生产成本.分离出的皂相经酸化转化为混合脂肪酸,混合脂肪酸用于酸催化的酯化反应.利用响应面法对酯化反应工艺参数进行了优化,并得到回归方程.方差分析结果表明:在各影响因素中,醇酸摩尔比对转化率的影响最大,其次是反应温度和反应时间,醇酸摩尔比和反应温度的交互作用显著.酯化反应优化后的工艺条件为醇酸摩尔比为5∶1,催化剂(H2SO4)添加量3%(wt.%),反应温度为87℃,反应时间4.74 h,在此条件下转化率达到92.5%. 相似文献
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以大豆油为原料,KOH作催化剂,通过大豆油与乙醇的酯交换反应合成了大豆油脂肪酸乙酯。应用响应曲面分析法中的Box-behnken模型对影响大豆油脂肪酸乙酯转化率的四个主要因素(催化剂用量、醇油摩尔比、反应温度、反应时间)进行了优化。研究表明大豆油脂肪酸乙酯的最佳合成工艺条件为:KOH用量1.3%,醇油比8.3∶1,反应温度74.8℃,反应时间130min。在此条件下,酯转化率达98.93%。 相似文献
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以单枞茶为实验材料,研究复合酶解辅助乙醇提取茶多酚的工艺条件,考察酶解温度、酶添加量、酶解pH、酶解时间、乙醇质量分数、料液比、提取时间、提取温度8个单因素对茶多酚提取率的影响。在单因素实验的基础上,通过正交实验优化提取工艺参数。结果表明:酶解温度60℃、酶添加量3.5%、酶解pH4.8的条件下酶解预处理3 h后,在乙醇质量分数为60%、提取温度为70℃、料液比为1︰50的条件下提取1.5 h,茶多酚的提取率达25.82%,与传统水提法相比,茶多酚提取率提高了69.87%。 相似文献
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以茶树[Camellia sinensis (L.) O. Kuntze]茶籽油为原料,研究了茶籽油甲酯化制备生物柴油的工艺条件。在单因素试验的基础上,选取反应温度、催化剂用量(占精炼油质量百分比)、反应时间和醇油摩尔比为影响因子,以酯交换率为响应值,应用Box-Behnken中心组合试验设计建立数学模型,进行响应面分析。结果表明,茶籽油制备生物柴油的最佳工艺条件为:反应温度58℃、催化剂用量1.05%、反应时间66min、醇油摩尔比9.7∶1。在此条件下,酯交换率达到98.73%。对生物柴油进行红外光谱和GC-MS分析,产品质量达到国家生物柴油标准。 相似文献
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Azhari M. Syam Robiah YunusTinia I.M. Ghazi Thomas S.Y. Choong 《Industrial Crops and Products》2012,37(1):514-519
Jatropha curcas oil (JCO) has a high content of free fatty acids and has been used extensively as a feedstock in biodiesel production. In the present study, the transesterification reaction of JCO to Jatropha curcas methyl ester (biodiesel) was performed in a continuous pulsed loop reactor under atmospheric conditions. The JCO was pre-treated prior to the reaction to reduce the free fatty acid content to below 1% (w/w). The operating parameters of the loop reactor were optimised based on the conversion of the JCO to Jatropha curcas biodiesel and included reaction temperature, molar ratio of oil to MeOH, reaction time and oscillation frequency. The findings show that the highest reaction conversion of 99.7% (w/w) was achieved using KOH catalyst and 98.8% conversion was obtained using NaOCH3 catalyst. The optimal operating conditions were a molar ratio of 6:1, an oscillation frequency of 6 Hz, temperature of 60 °C, feedstock FFA content of 0.5% (w/w) and only 10 min of reaction time. As a commercial commodity, the physical properties of biodiesel were analysed, and they compared well with the characteristics of fossil-based diesel fuel. 相似文献
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有机硅氧烷接枝改性天然胶乳的制备及结构表征 总被引:2,自引:1,他引:1
采用接枝共聚制备有机硅氧烷接枝改性天然胶乳,着重考察偶联剂种类和用量、引发剂用量、胶乳浓度、反应温度、反应时间和有机硅氧烷种类及用量等对有机硅在接枝共聚反应中的转化率和接枝率的影响,并采用正交设计试验,探索有机硅氧烷改性天然胶乳的适宜工艺条件。结果表明∶VD4接枝改性天然胶乳的转化率和接枝率均比D2的要高;与其他偶联剂相比,A-171的接枝率也较高;随着有机硅单体用量的增加、反应时间延长、反应温度升高,有机硅单体的转化率和接枝率都升高。有机硅氧烷改性天然胶乳的适宜工艺条件∶胶乳浓度为50%,反应温度为55℃,反应时间为4h,偶联剂A-171用量为1.2%(占橡胶的质量百分率,下同),有机硅用量为15%,引发剂用量为1.0%。IR分析结果表明∶有机硅氧烷与天然橡胶分子链存在接枝共聚。 相似文献
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新型固体碱催化大豆油制备生物柴油的工艺研究 总被引:1,自引:0,他引:1
制备了新型固体碱催化剂KNO3/AlSBA-15,并以此催化大豆油与甲醇酯交换反应制备生物柴油,对其工艺条件进行了优化.结果表明:醇油物质的量比为12∶1,催化剂用量为大豆油质量的3%,反应温度65C,反应时间4h,生物柴油的产率可达81%以上.该催化剂对酯交换制备生物柴油具有较高的催化活性和良好的重复使用性. 相似文献
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Physicochemical properties of stillingia oil: Feasibility for biodiesel production by enzyme transesterification 总被引:3,自引:0,他引:3
The physicochemical properties, fatty acids profile and triglyceride compositions of the stillingia oil were analyzed. The stillingia oil was found to contain 98.79% neutral lipids, 0.22% phospholipids and 0.99% glycolipids, which exhibited varying contents of fatty acids. The major triglyceride was double linoleic acid linolenic acid triglyceride, which accounted for approximately 79.49% of the total triglycerides. Preparation of biodiesel from stillingia oil was investigated by enzyme transesterification with methanol as the acyl acceptor. The results showed that lipase type (Novozym 435, Lipozyme TLIM and Lipozyme RMIM), reaction systems (in solvent-free and tert-butanol system) and operational parameters (lipase loading, reaction time, temperature, and molar ratio of alcohol to oil) influenced the biodiesel yield. Fuel properties of biodiesel from stillingia oil were evaluated and all were in acceptable range for use as biodiesel in diesel engines, and had remarkable flash point and satisfactory cold flow properties. It was concluded that stillingia oil was an alternative potential feedstock oil for biodiesel production. 相似文献
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分子筛负载杂多酸催化大豆油制备生物柴油 总被引:2,自引:0,他引:2
采用等体积浸渍法制备了负载型催化剂PW/MCM-41,并以此催化大豆油与甲醇酯交换反应制备生物柴油.考察了磷钨酸负载量和催化剂焙烧温度对催化剂催化活性的影响,以及醇油物质的量比、催化剂用量、反应时间和反应温度对生物柴油产率的影响.结果表明:磷钨酸负载量为30%、焙烧温度为300℃时,催化剂活性最高.酯交换反应的最佳条件... 相似文献
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Surface modification of polyester fabrics by enzyme treatment 总被引:1,自引:0,他引:1
In this study, the effect of enzymatic hydrolysis using lipase and cutinase on poly(ethyleneterephthalate) (PET) fabrics was
investigated in an attempt to improve the hydrophilicity of these fabrics. The hydrolytic activity of the enzymes was expressed
for variations in pH levels, temperatures, enzyme concentrations, and treatment times. The effects of using a nonionic surfactant
were examined by measuring moisture regain and surface wettability. Finally, the fabric characteristics that were affected
by enzyme treatment were evaluated by tensile strength and scanning electron microscopy. The optimal treatment conditions
for lipase were determined to be a pH of 4.2, a temperature of 50 °C, a lipase concentration of 100 %, and a treatment time
of 90 min; those for cutinase were determined to be a pH of 9.0, a temperature of 50 °C, a cutinase concentration of 100 %,
and a treatment time of 60 min. At optimal enzymatic treatment conditions, we got the significant results of increase on the
moisture regain and the water contact angle (WCA) and water absorbency effectively decreased. Triton X-100 facilitated cutinase
hydrolysis on PET fabrics; however, it was ineffective for lipase. With enzymatic treatment, the tensile strength did not
decrease. 相似文献
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为研究辣木多糖的酶促提取工艺和辣木不同部位的多糖含量,在单因素试验的基础上,以多糖提取率为指标,选择纤维素酶用量、提取温度、提取时间、液料比为试验因素,采用二次回归正交旋转组合设计对纤维素酶辅助提取辣木多糖的工艺参数进行优化,并在此基础上研究辣木不同部位的多糖含量差异。4种因素对辣木多糖提取率的影响顺序依次为:纤维素酶用量>提取温度>液料比>提取时间。建立辣木多糖提取率(Y)与纤维素酶用量(X1)、提取温度(X2)、提取时间(X3)、液料比(X4)的二次正交回归模型:Y=18.6602+0.8134X1+0.7572X2–0.4312X3+0.6909X4–0.5181X12–0.4935X22–0.6277X42,该模型拟合度好,4个因素均对多糖提取率有显著影响(p<0.05)。通过回归模型获得优化的提取工艺为:纤维素酶用量1.60%,提取温度53℃,提取时间68 min,液料比52∶1,在此条件下辣木多糖提取率为19.83%,实际值与预测值一致。辣木不同部位的多糖含量结果表明,辣木根、花、嫩叶、茎中均含有丰富的多糖,其中根中含量最高且极显著高于其他部位(p<0.01),可进一步开发利用。采用二次回归正交旋转组合设计优化得到的辣木多糖酶促提取工艺条件准确可靠,可有效提高辣木多糖提取率并可在生产中推广应用。 相似文献