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HDPE,LLDPE和LDPE三种不同分子链结构聚乙烯的辐照交联研究 总被引：1，自引：0，他引：1
对高密度聚乙烯（ＨＤＰＥ）、线性低密度聚乙烯（ＬＬＤＰＥ）和低密度聚乙（ＬＤＰＥ）在＾６０Ｃｏγ射线辐照前后的性能，主要是弟胶含量和机械性能，进行了分析对比。结果表明，在相同的剂量率和剂量辐照，聚惭烯试样的凝胶含量顺序ＬＤＰＥ〉ＬＬＤＰＥ〉ＨＤＰＥ；交联引起的拉伸强度变化率为ＬＤＰＥ〉ＬＬＤＰＥ〉ＨＤＰＥ；交联引起的断裂伸长率为ＨＤＰＥ〉ＬＬＤＰＥ〉ＬＤＰＥ《 相似文献
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固氨粪产碱菌野生型Ａ１５０１菌株及其胞外多糖（ＥＰＳ）突变株Ｅｘｏ＋＋（Ａ１５３２）和ＥｘＯ－（Ａ１５３１）,以及ｎｉｆＡ和ｎｔｒＣ－ｎｉｆＡ转化子（Ａ１５１３和Ａ１５２３）的ＥＰＳ,由高分子量（２５０ｋＤ左右）组分（ＥＰＳＨ）和低分子量小于４０ｋＤ组分（ＥＰＳＬ）组成。两个组分中均含有葡萄糖、半乳糖、果糖和戊糖,其主要成分葡萄糖和半乳糖的分子摩尔比：Ａ１５０１－ＥＰＳＨ为２：１、ＥＰＳＬ为３：１;Ａ１５３１－ＥＰＳＨ为２：１、ＥＰＳＬ为１：１;Ａ１５３２－ＥＰＳＨ为８：１、ＥＰＳＬ为５：１;Ａ１５１３－ＥＰＳＨ和ＥＰＳＬ均为４：１;Ａ１５２３－ＥＰＳＨ为４：１、ＥＰＳＬ为８：１。高分子量ＥＰＳ中还含有多肤,其氨基酸组分在各突变株和转化子之间差异明显,而ＥＰＳＬ中仅含有痕量多肽。 相似文献
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小麦雄性不育与内源激素关系的初步研究 总被引：3，自引：3，他引：3
以小麦核质互作雄性不育（ＣＭＳ）和化学杂交剂（ＣＨＡ）诱导的雄性不育为材料，应用ＥＬＩＳＡ方法，研究了雄性不育与内源激素含量的关系。结果表明Ｔ型、Ｋ型ＣＭＳ和ＢＡＵ２、ＳＣ２０５３两种ＣＨＡ诱导的雄性不育均与ＩＡＡ含量降低有关。Ｔ型、Ｋ型ＣＭＳ不育花药内ＡＢＡ、ＺＲ和ＤＨＺＲ含量较保持系增加；而ＣＨＡ诱导的雄性不育ＡＢＡ含量随小孢子发育较对照降低，ＺＲ含量较对照降低，ＤＨＺＲ含量较对照增加。内源激 相似文献
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大目金枪鱼加工副产物中鱼油提取制备及EPA分离纯化 总被引：1，自引：0，他引：1
为获得较高纯度的乙酯型EPA金枪鱼油,以大目金枪鱼加工副产物为原料,通过响应面法优化酶辅助提取粗鱼油的工艺参数,并采用粗鱼油精制、化学催化乙酯化、多级分子蒸馏和尿素包合初步纯化、精馏高纯化,以及合成银离子功能材料螯合制备分离等一系列技术手段进行制备。结果表明,优化的酶解提取法工艺条件为:酶解pH值8.5、酶解温度45℃、酶解时间3 h,此条件下粗鱼油提取率高达43.69%。乙酯化鱼油经多级分子蒸馏和尿素包合处理后,EPA和DHA总量可达80.00%以上,且分别占46.34%和34.58%。对该鱼油进行精馏试验,获得EPA乙酯,其含量达到82.40%,得率为39.00%,在此基础上,进一步使用银硫醇硅胶制备得到96.30%的EPA乙酯,得率为32.90%。本研究结果为鱼类加工副产物的高值化利用提供了一定参考。 相似文献
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用聚丙烯酰胺凝胶圆盘电泳法，对摩拉（Ｍｕｒｒａ）、尼里（Ｎｉｌｉ－Ｒａｖｉ）和三品系杂交种［Ｎｉ♂×（Ｍｕ♂×Ｎａｒｍｉｎｇ♀）♀）的水牛奶ＡＬＰ及ＬＤＨ同工酶进行了研究．结果表明：三种水牛奶ＡＬＰ及ＬＤＨ都有三种同工酶，只有ＡＬＰ３和ＬＤＨ１出现的比例为１００％，其余的均小于１００％．ＡＬＰ同工酶相对总活力在种间及尼里内与产奶量呈正相关趋势，而在三品杂和摩拉内则相反．ＡＬＰ三种同工酶的相对活力均表现出杂种优势，且ＡＬＰ１和ＡＬＰ２与品种的产奶量呈正相关趋势；尼里的三种酶、三品杂的ＡＬＰ３、摩拉的ＡＬＰ２和ＡＬＰ３与产奶量呈正相关趋势，其余的则相反，三种奶的ＡｓＰ是ＡＬＰ３＞＞ＡＬＰ２（或ＡＬＰ１）＞ＡＬＰ１（或ＡＬＰ２）。两性载体电解质是水牛奶ＡＬＰ的较强抑制剂．ＬＤＨ１酶活力相对百分含量，在种间表现出杂种优势，且与产奶量呈正相关趋势，而ＬＤＨ２和ＬＤＨ３则否；尼里三种酶活力的大小排列与酶的序号一致，三品杂和摩拉则否；在各品种内，ＬＤＨ３与产奶量呈正相关趋势，ＬＤＨ１和ＬＤＨ２则相反。 相似文献
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应用荧光探针ＦＭＡ和荧光胺，证明ＥＰＳ中多肽的一些基因如ＳＨ基和ＮＨ基参予了与 系粘质的相互作用。ＮＨ４＾＋浓度可诱导ＥＰＳ中ＳＨ基和ＮＨ基数量的变化，并导致ＥＰＳ中多肽的构象改变，ＥＰＳ中的这些基因在粪产碱菌与水稻根系的结合过程起了重要作用。 相似文献
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氯化胆碱对甘蔗光合性能及糖含量的影响 总被引：1，自引：0，他引：1
以不同浓度的氯化胆碱（ＣＣ）处理田间栽培甘蔗。经合适浓度的ＣＣ处理的甘蔗叶绿素含量、叶内Ｍｇ２＋-ＡＴＰａｓｅ和Ｃａ２＋-ＡＴＰａｓｅ，ＮＡＤＰ一苹果酸酶和磷酸烯醇式丙酮酸（ＰＥＰ）羧化酶等活性，叶绿体的希尔（Ｈｉｌｌ）反应活力和光合速率都有不同程度的提高，甘蔗的株高、茎粗、蔗茎含糖量也有所提高。 相似文献
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喷钙对苹果果实生理特性的影响 总被引：18，自引：0，他引：18
采用田间调查、小区试验及生理生化分析相结合的方法研究钙与苹果果实生理性病害发生的关系及其防治机理。结果表明，与健康果比较，发病果全钙含量及不提取态和１ｍｏＬ／Ｌ ＮａＣＩ提取态钙含量大为减少，果实氮／钙比、果胶甲脂酶（ＰＥＡ）活性、超氧化物歧化酶（ＳＯＤ）和过氧化物酶（ＰＯＤ）活性及丙二醛（ＭＤＡ）含量较高。幼果期喷钙显著增加了单果重，降低了苦痘病发病率，改善了苹果品质，并可增加果实全钙、水提取态 相似文献
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Enrichment of eicosapentaenoic acid from sardine oil with Delta5-olefinic bond specific lipase from Bacillus licheniformis MTCC 6824 总被引：1，自引：0，他引：1
Lipase derived from Bacillus licheniformis MTCC 6824 was purified to homogeneity by anion exchange chromatography on Amberlite IRA 410 (Cl-) and gel filtration using Sephadex G-100 as judged by denaturing polyacrylamide gel electrophoresis. The purified lipase was used for hydrolysis of triacylglycerol in sardine oil to enrich Delta5-polyunsaturated fatty acids (Delta5-PUFAs) namely, arachidonic acid (5,8,11,14-eicosatetraenoic acid, ARA, 20:4n-6) and eicosapentaenoic acid (5,8,11,14,17-eicosapentaenoic acid, EPA, 20:5n-3). The individual fatty acids were determined as fatty acid methyl esters (FAMEs) by gas-liquid chromatography and gas chromatography-mass spectroscopy as FAMEs and N-acyl pyrrolidides. The enzyme exhibited hydrolytic resistance toward ester bonds of Delta5-PUFAs as compared to those of other fatty acids and was proved to be effective for increasing the concentration of EPA and ARA from sardine oil. Utilizing this fatty acid specificity, EPA and ARA from sardine oil were enriched by lipase-mediated hydrolysis followed by urea fractionation at 4 degrees C. The purified lipase produced the highest degree of hydrolysis for SFAs and MUFAs (81.5 and 72.3%, respectively, from their initial content in sardine oil) after 9 h. The profile of conversion by lipase catalysis showed a steady increase up to 6 h and thereafter plateaued down. Lipase-catalyzed hydrolysis of sardine oil followed by urea adduction with methanol provided free fatty acids containing 55.4% EPA and 5.8% ARA, respectively, after complexation of saturated and less unsaturated fatty acids. The combination of enzymatic hydrolysis and urea complexation proved to be a promising method to obtain highly concentrated EPA and ARA from sardine oil. 相似文献
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Eicosapentaenoic acid (EPA) derived from chemically hydrolyzed sardine oil was concentrated by urea fractionation using methanol at different temperatures (2, 4, and 6 degrees C) and urea/fatty acid ratios (2:1, 3:1, and 4:1 w/w) and purified by argentation neutral alumina column chromatography. The individual fatty acids were determined as fatty acid methyl esters (FAME) by gas-liquid chromatography and gas chromatography-mass spectroscopy as FAME and N-acyl pyrrolidides. In the mass fragmentation pattern of FAME, the base peak was assigned to be the 1-methoxyethenol moiety (m/z = 74) obtained by McLafferty rearrangement. Formation of the cyclic tropylium ion (m/z = 91) in fatty acids with four or more double bonds was apparent in FAME-PUFAs. The base peak of N-acyl pyrrolidides was the McLafferty rearrangement ion, 1-(pyrrolidin-1-yl)ethenol (m/z = 113). The highest concentration of EPA (47.78%) was obtained at the crystallization temperature of 4 degrees C with a urea/fatty acid ratio of 4:1 (w/w) with 93.74% yield. After complexation of saturated and less unsaturated fatty acids by urea complexation, argentation chromatography resulted in an EPA of high purity (99.6%) with an overall recovery of 54.09% using 50% diethyl ether/n-hexane as eluting solvent. The peroxide (POV) and thiobarbituric acid (TBS) values were found to be highest (4.0 mequiv of O2/kg and 5.2 mg of malondialdehyde/kg, respectively) during urea fractionation at the higher crystallization temperature (6 degrees C) and higher urea/fatty acid ratio (4:1). Keywords: Sardine oil; eicosapentaenoic acid (EPA); fatty acid methyl esters (FAME); urea fractionation; argentation column chromatography. 相似文献
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Saponarin, a flavonoid found in young green barley leaves, possesses potent antioxidant activities, which are determined by its inhibition of malonaldehyde (MA) formation from various lipids oxidized by UV light or Fenton's reagent. Lipids used were squalene, ethyl linoleate, ethyl linolenate, ethyl arachidonate, octadecatetraenoic acid (ODTA), eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), cod liver oil, lecithin I, lecithin II, and blood plasma. The addition of saponarin inhibited the formation of MA from squalene upon UV irradiation at the level of 2 μmol/mL by almost 100%, whereas BHT inhibited its formation by 75% at the same level. Saponarin showed potent antioxidant activity toward fatty acid ethyl esters at levels >100 μg/mL. Saponarin inhibited MA formation in ODTA by 60%, in EPA by 50%, and in DHA by 43% at the level of 15 μmol/mL. Saponarin exhibited strong antioxidant activities with dose-response levels toward cod liver oil and lipoproteins (lecithins I and II), higher than those of α-tocopherol. A mixture of saponarin/lutonarin (4.5:1, w/w) inhibited MA formation appreciably from all lipids tested with dose response. This mixture exhibited highest effect toward cod liver oil (86%), followed by DHA, lecithin II, blood plasma, EPA, and lecithin I. Supplementation of young green barley leaves containing saponarin should be beneficial to health and may prevent diseases caused by oxidative damage such as various cancers, inflammations, and cardiovascular diseases. 相似文献
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Sanden M Stubhaug I Berntssen MH Lie Ø Torstensen BE 《Journal of agricultural and food chemistry》2011,59(23):12697-12706
The objective of the present study was to investigate the effects of replacing high levels of marine ingredients with vegetable raw materials and with emphasis on lipid metabolism and net production of long-chain polyunsaturated ω-3 fatty acids (EPA + DHA). Atlantic salmon were fed three different replacement vegetable diets and one control marine diet before sensory attributes, β-oxidation capacity, and fatty acid productive value (FAPV) of ingested fatty acids (FAs) were evaluated. Fish fed the high replacement diet had a net production of 0.8 g of DHA and a FAPV of 142%. Fish fed the marine diet had a net loss of DHA. The present work shows that Atlantic salmon can be a net producer of marine DHA when dietary fish oil is replaced by vegetable oil with minor effects on sensory attributes and lipid metabolism. 相似文献
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Ethyl esters (FAEE) and trideuterium-labeled methyl esters (d3-FAME) of fatty acids were prepared and investigated regarding their suitability as internal standards (IS) for the determination of fatty acids as methyl esters (FAME). On CP-Sil 88, ethyl esters of odd-numbered fatty acids eluted approximately 0.5 min after the respective FAME, and only coelutions with minor FAME were observed. Depending on the problem, one or even many FAEE can be added as IS for the quantification of FAME by both GC-FID and GC-MS. By contrast, d3-FAME coeluted with FAME on the polar GC column, and the use of the former as IS requires application of GC-MS. In the SIM mode, m/z 77 and 90 are suggested for d3-methyl esters of saturated fatty acids, whereas m/z 88 and 101 are recommended for ethyl esters of saturated fatty acids. These m/z values give either no or very low response for FAME and can thus be used for the analysis of FAME in food by GC-MS in the SIM mode. Fatty acids in sunflower oil and mozzarella cheese were quantified using five saturated FAEE as IS. Gravimetric studies showed that the transesterification procedure could be carried out without of loss of fatty acids. GC-EI/MS full scan analysis was suitable for the quantitative determination of all unsaturated fatty acids in both food samples, whereas GC-EI/MS in the SIM mode was particularly valuable for quantifying minor fatty acids. The novel GC-EI/MS/SIM method using fatty acid ethyl esters as internal standards can be used to quantify individual fatty acids only, that is, without determination of all fatty acids (the common 100% method), although this is present. This was demonstrated by the exclusive quantification of selected fatty acids including methyl-branched fatty acids, erucic acid (18:1n-9trans), and polyunsaturated fatty acids in cod liver oil and goat's milk fat. 相似文献
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为了解决鱼油原料市场日益突出的掺伪问题,本研究采用气相色谱法测定沙丁鱼及5种可能掺伪海水鱼的鱼油脂肪酸组成,并运用主成分分析（PCA）探究鱼油中各脂肪酸的变化规律,筛选出可能掺伪的海水鱼鱼油;运用偏最小二乘判别分析（PLS-DA）和多元逐步线性回归分析建立沙丁鱼油的掺伪鉴别模型。结果表明,5种鱼油与沙丁鱼油的脂肪酸组成有不同程度的差异,其中鳀鱼油与沙丁鱼油脂肪酸组成最为接近。PCA分析的总贡献率为89.8%,说明分析结果具有良好的代表性,鳀鱼油可以拟作沙丁鱼的掺伪油。PLS-DA分析认为沙丁鱼掺伪油的6种特征脂肪酸分别是二十碳五烯酸（EPA）、二十二碳六烯酸（DHA）、棕榈酸、棕榈油酸、二十二碳烯酸和油酸。沙丁鱼油掺伪鉴别模型所得相关系数（R2）分别为0.927、0.963、0.987、0.991,各模型平均误差分别为2.20%、1.38%、1.19%、0.83%,表明模型准确性较好。因此,该模型可实现鳀鱼油掺伪沙丁鱼油的定量识别,在鉴别沙丁鱼油掺伪上具有一定的可行性。 相似文献
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为比较不同生长阶段墨瑞鳕肌肉中脂肪酸组成的变化,本研究通过气相色谱技术测定墨瑞鳕幼鱼、成鱼、亲鱼肌肉中脂肪酸含量,并对脂肪酸组成进行主成分分析。结果表明,3个不同生长阶段墨瑞鳕的不饱和脂肪酸(UFA)总量分别为52.2%、58.2%、60.1%;在高度不饱和脂肪酸(HUFA)中DHA含量均最高。随着鱼体生长,墨瑞鳕棕榈油酸、油酸、亚油酸、亚麻酸含量均呈上升趋势,从高到低依次为亲鱼>成鱼>幼鱼;肉豆蔻酸、花生一烯酸、花生四烯酸、EPA、DHA 含量呈下降趋势,从高到低依次为幼鱼>成鱼>亲鱼;UFA总量和单不饱和脂肪酸(MUFA)含量呈上升趋势,从高到低依次为亲鱼>成鱼>幼鱼;多不饱和脂肪酸(PUFA)总量和必需脂肪酸(EFA)总量含量呈先升后降趋势,从高到低依次为成鱼>亲鱼>幼鱼。墨瑞鳕不同生长阶段脂肪酸含量大部分存在显著差异,特别是幼鱼与成鱼的脂肪酸含量(除二十碳三烯酸外)均存在显著差异;肉豆蔻酸、花生一烯酸、花生四烯酸、EPA和DHA等5种脂肪酸是墨瑞鳕的主要特征脂肪酸,这5种主要特征脂肪酸之间均互呈强正相关。随着墨瑞鳕的生长发育应及时提高相应阶段功能性脂肪酸的比例,降低相应阶段呈强负相关的主要特征脂肪酸的比例。本研究结果为墨瑞鳕的开发利用以及饲料营养需求等提供了理论参考。 相似文献
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Pérez-Camino MC Moreda W Mateos R Cert A 《Journal of agricultural and food chemistry》2002,50(16):4721-4725
A simple and precise analytical method was developed for the simultaneous determination of squalene and methyl, ethyl, propyl, and butyl esters of fatty acids present in olive and olive pomace oils. A fraction containing squalene and fatty acid alkyl esters was isolated from the oil by solid phase extraction on silica gel cartridges and quantitatively analyzed by gas chromatography. A modification of the procedure allowed the isolation of squalene and esters separately. Repeatability and recovery of the method were good. The method was applied to extra and lampant virgin olive oil categories and also to oils obtained from olive pomace by second centrifugation and solvent extraction. Extra virgin olive oils contained low amounts of fatty acid methyl and ethyl esters, while oils obtained from altered olive or olive pomace showed high concentrations of fatty acid alkyl esters, mainly ethyl esters. Correlation between oil acidity and ethyl esters concentration was poor. 相似文献
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The ability of different lipases to incorporate omega3 fatty acids, namely, eicosapentaenoic acid (EPA, C20:5n-3), docosapentaenoic acid (DPA, C22:5n-3), and docosahexaenoic acid (DHA, C22:6n-3), into a high-laurate canola oil, known as Laurical 35, was studied. Lipases from Mucor miehei (Lipozyme-IM), Pseudomonas sp. (PS-30), and Candida rugosa (AY-30) catalyzed optimum incorporation of EPA, DPA, and DHA into Laurical 35, respectively. Other lipases used were Candida anatrctica (Novozyme-435) and Aspergillus niger (AP-12). Response surface methodology (RSM) was used to obtain a maximum incorporation of EPA, DPA, and DHA into high-laurate canola oil. The process variables studied were the amount of enzyme (2-6%), reaction temperature (35-55 degrees C), and incubation time (12-36 h). The amount of water added and mole ratio of substrates (oil to n-3 fatty acids) were kept at 2% and 1:3, respectively. The maximum incorporation of EPA (62.2%) into Laurical 35 was predicted at 4.36% of enzyme load and 43.2 degrees C over 23.9 h. Under optimum conditions (5.41% enzyme; 38.7 degrees C; 33.5 h), the incorporation of DPA into high-laurate canola oil was 50.8%. The corresponding maximum incorporation of DHA (34.1%) into Laurical 35 was obtained using 5.25% enzyme, at 43.7 degrees C, over 44.7 h. Thus, the number of double bonds and the chain length of fatty acids had a marked effect on the incorporation omega3 fatty acids into Laurical 35. EPA and DHA were mainly esterified to the sn-1,3 positions of the modified oils, whereas DPA was randomly distributed over the three positions of the triacylglycerol molecules. Meanwhile, lauric acid remained esterified mainly to the sn-1 and sn-3 positions of the modified oils. Enzymatically modified Laurical 35 with EPA, DPA, or DHA had higher conjugated diene (CD) and thiobarbituric acid reactive substance (TBARS) values than their unmodified counterpart. Thus, enzymatically modified oils were more susceptible to oxidation than their unmodified counterparts, when both CD and TBARS values were considered. 相似文献