黄山野菊花中绿原酸含量的测定

采用紫外分光光度法对产于皖南黄山山脉的黄山野菊花中的绿原酸含量进行了测定,本法准确、精密度高、重现性好,绿原酸浓度线性范围5~20 mg/L(r=0.999 6);平均回收率为102.0%,RSD为0.83。该法可作为黄山野菊花及其制剂质量控制的—种方法。     

葵花籽粕中提取绿原酸的工艺优化

研究了从葵花籽粕中提取绿原酸的工艺。通过对甲醇浓度、温度、料液比、提取时间等因素对提取效率的影响,在运用旋转蒸发仪下得出绿原酸提取工艺的最佳工艺参数：甲醇浓度70%、温度45℃、提取时间1.5 h、料液比1∶10（W/V）。采用紫外分光光度法对绿原酸产品进行检测。在325 nm波长下,得到绿原酸的最大峰值,计算得率为3.13%。     

金银花中绿原酸防晒作用研究

考察了金银花中绿原酸的紫外吸收性能、光照稳定性、酸碱稳定性及其防晒产品的防晒性能。结果显示,金银花提取物在280~350 nm内具有良好的紫外吸收性能。绿原酸具有光化学活性,发生光降解反应,提取物溶液中绿原酸的保留率随光照时间的延长而降低,光照8 h提取物溶液中绿原酸的保留率为85.6%。在pH=3~7时绿原酸相对稳定。金银花防晒霜体外评价SPF值与金银花提取物中绿原酸含量有关,防晒霜中绿原酸质量分数达2.15%时SPF值为15。     

塑料玩具中邻苯二甲酸酯类环境激素检测方法的研究

采用高效液相色谱法对玩具中5种邻苯二甲酸酯类物质进行同时分离和检测,对样品的提取、净化以及检测的色谱条件进行筛选和优化.以shim-pack VP-ODS为分离柱;流动相为V(甲醇):V(水)=90:10,紫外检测波长为230nm.该方法所测得的5种邻苯二甲酸酯类物质在0.5-1000mg/L内具有良好的线性,检出限达0.34-0.96ug/L.加标回收率在93.00%-105.23%.该方法适合各种玩具中邻苯二甲酸酯类物质的分析.     

均匀设计法优化杜仲叶中绿原酸的提取工艺

目的:筛选杜仲叶中绿原酸提取最佳工艺条件.方法:采用均匀设计安排试验,以紫外吸光度为考察指标,数据经多元回归处理,建立绿原酸的定量评价方法.对杜仲叶中绿原酸提取工艺中影响效果的乙醇浓度、料液比、超声时间三因素及条件进行优化,根据回归方程并结合经验,优选绿原酸提取工艺的最佳实验条件.结果:选择乙醇浓度50%,超声时间50min,料液比1/30,超声频率40Hz,提取温度45℃为最佳条件,提取次数为4次.     

紫外分光光度法测定地下水中的石油类物质

采用紫外分光光度法测定地下水中的石油类物质。样品中的石油类物质被正己烷萃取,萃取液经过无水硫酸钠脱水,再经硅酸镁吸附除去动植物油类等极性物质后进行测定。对检测方法的检出限、精密度、准确度进行了测定。结果表明,曲线相关系数均在0.999以上,检出限、精密度和准确度的结果均符合《水质石油类的测定紫外分光光度法(试行)》(HJ 970-2018)中的要求。该方法灵敏度高,操作简便、快速,可以满足地下水石油类分析的要求。     

绿茶中绿原酸提取方法的比较

绿茶中含有的绿原酸是茶多酚的组分之一,能增加肠胃蠕动,促进胃液分泌,能止血,增加白细胞及抗病毒作用,所以对茶叶中绿原酸的提取很有意义,提取绿原酸方法较多,常见的方法有水浴回流法、超声波法、水浸提法、纤维素酶法,如何找到一种成本低,提取率高的方法,对于茶叶的深加工及其药用成分的开发有着重要的意义。本文用这四种方法对绿茶中的绿原酸进行提取,提取率为:水浴回流法0.85%±0.02%、超声波法1.01%±0.00%、水浸提法0.47%±0.01%、纤维素酶法1.03%±0.01%,纤维素酶法为最佳的提取方法。     

杜仲叶绿原酸提取物对胰脂肪酶活性抑制的研究

通过对紫外分光光度计的运用来建立一种快速高效,低成本的方法来研究杜仲叶中绿原酸提取物对胰脂肪酶活性的影响。该实验中并未选用大型仪器来研究,而是选用常见的紫外分光光度计,实验过程中本法能达到良好的线性关系,其R=0.9991,能够达到一般实验要求。实验结果得出杜仲叶中绿原酸提取物抑制脂肪酶的IC50值为0.00126 mg/m L,介于奥利司他与标准品之间,且高于标准品。     

PET的紫外老化性能及机理研究

采用力学、紫外-可见光分析和热失质等测试手段研究了PET改性料的紫外老化性能及老化机理。结果表明:复合助剂的加入能显著提升体系的力学性能保持率,进而提升其紫外老化寿命,提升的幅度随复合助剂中耐紫外剂含量的增加而显著增加。DSC分析表明,随着复合助剂的引入和老化的进行,改性料结晶度增加。文中进一步讨论了PET改性料的紫外老化机理。紫外-可见光分析表明,紫外老化能产生醌类和双醌类物质,进而提升PET改性料的紫外吸收度。     

超声波法提取金银花中的绿原酸

用超声波法提取金银花中的绿原酸,并与传统的水提、醇提工艺进行了比较,采用薄层层析法定性检验,紫外分光光度法测定绿原酸的含量.结果表明,超声波法的提取率高于传统溶剂提取法.在10倍量pH=4的70％乙醇中预浸泡24 h,再用超声波提取4次,每次30 min,绿原酸收率最高,含量可达9.58％.     

HPLC测定金银忍冬叶、花、果实中绿原酸的含量

建立了反相高效液相色谱法测定金银忍冬叶、花和果实中的绿原酸含量的测定方法。利用超声波辅助提取金银忍冬叶、花和果实中的绿原酸,采用采用反相高效液相色谱法测定金银忍冬叶、花和果实中的绿原酸含量。结果表明:在流动相为甲醇(A)∶1.0%的冰醋酸溶液(B)=27∶73,色谱柱为Alltima C18Column(250 mm×4.6 mm,5μm),流动相流速为1.0 mL/min,检测波长为327 nm,柱温为25℃的实验条件下测定金银忍冬叶、花和果实中的绿原酸含量分别为:(31.64±2.21)mg/g,(17.45±1.05)mg/g,(5.14±1.39)mg/g,且宁夏金银忍冬植株不同部位中绿原酸类化合物的含量分布为:叶花果实。回收率为99.74%,RSD为0.23%。所建立的方法稳定,操作简单,结果可靠。     

Bioactive Compounds,Antioxidant Activities and Heat Stability of Corn Oil Enriched with Tunisian Citrus aurantium L. Peel Extract

This study was designed to examine physicochemical composition, antioxidant activities and heat stability of corn oil enriched with bitter orange peel. Volatile compounds composition of corn oil flavored with Citrus aurantium peel was investigated. Flavored oil total aroma content (2.6 mg/mg oil) was mainly represented by monoterpene hydrocarbons and limonene was the major one (2.49 mg/mg oil). Flavored oil methanolic extract was characterized by total phenol content of 1.22 mg GAE/kg. Chlorogenic, ferulic and p-coumaric acids were the major phenolic components of the flavored oil extract (34.33, 30.24 and 19.39 %, respectively). It was also characterized by a higher chlorophylls and carotenoids contents than the refined one. Antioxidant activities of methanolic extracts of both samples were determined using four assays: DPPH, reducing power, β-carotene bleaching and metal chelating tests. In β-carotene bleaching and DPPH radical scavenging assays, flavored oil methanolic extract showed higher activities than the control. It was characterized by a total antioxidant activity of 4.08 mg GAE/kg and an EC₅₀ value of 3.14 mg/mg oil. Its concentration providing 50 % inhibition (IC₅₀) was 0.53 mg/mg oil in the DPPH test and 4.08 mg/mg oil in the β-carotene bleaching test. However, refined corn extract showed significantly lower antioxidant activities (p < 0.05). Results of the oxidative stability index showed bitter orange peel effectiveness against thermal oxidation based on the increased induction time observed in flavored oil (5.95).     

HPLC同时测定蒲公英中咖啡酸和绿原酸的含量研究

目的:建立蒲公英中咖啡酸和绿原酸含量的HPLC测定方法。方法:采用Agilent ZorbaxSB-C1(85μm,150 mm×4.6 mm),流动相为甲醇-磷酸盐缓冲液(23:77,V/V),pH=4.0,流速0.8 mL/min,检测波长为323 nm,柱温为室温。结果:在0.00780～0.04160 mg/mL范围内咖啡酸含量与其峰面积呈良好的线性关系,平均加样回收率为98.92%;在0.00848～0.04784 mg/mL范围内绿原酸含量与其峰面积呈良好的线性关系,平均加样回收率为99.13%。结论:采用HPLC测定蒲公英中咖啡酸和绿原酸的含量简便、准确、选择性好,可用于蒲公英中咖啡酸和绿原酸的含量测定。     

Phospholipid profiles in the salivary glands of rats of different ages

It has been reported that diabetes and Sj?gren's syndrome patients exhibit variations in the amount of salivation and in the lipid components in saliva and salivary glands. We examined whether lipid compositions, especially phospholipid ones in the salivary glands of rats varied with aging. We analyzed phospholipid and fatty acid compositions in the salivary glands of young (5 to 6 weeks), adult (20 weeks), and old (50 weeks) rats and biochemical components in their blood. The aging (adult and old) rats had higher triacylglycerol, total lipid, total cholesterol and glucose contents in the plasma than the young one. The aging ones also had higher total lipid contents in the major salivary glands (parotid, submandibular and sublingual glands). They had higher wet weights of the major salivary glands and epididymal fat pads than the young ones, but had lower ratios of the major salivary glands to body weight. All of them had high phospholipid contents in the parotid and submandibular glands as compared to sublingual gland, but the aging ones had lower percentage of phospholipid contents of all salivary glands. Phosphatidylcholine and phosphatidylethanolamine were predominant among the phospholipids in the major salivary glands, and little difference was observed in phospholipid composition among the three groups. Palmitic and stearic acids (saturated acids), and linoleic, oleic and arachidonic acids (unsaturated acids) were major components of fatty acids of phospholipids in the major salivary glands. The aging ones had higher linoleic and lower arachidonic acid contents in the glands than the young one. In summary, the aging rats had higher total lipid contents than the young ones and had lower phospholipid contents of the major salivary glands. The n-6 fatty acid contents differed between aging and young ones. The results suggest that phospholipids in the major salivary glands change with the development of rat.     

Monthly variations of milk composition with special regard to fatty acids depending on season and farm management systems - Conventional versus ecological

During one year's period bulk milk samples were collected monthly from three different types of farms: 1. conventional farming, indoor feeding with silages throughout the year. 2. conventional farming, grazing during summer season, 3. ecological farming, grazing during summer season. The milk protein, fat and ash contents were significantly lower in ecologically kept dairy cows. The highest percentage of saturated fatty acids was found in the indoor group, whereas the trans fatty acid and linolenic acid contents were significantly higher in the ecological group. Dairy products are major sources of conjugated linoleic acid (anticarcinogens). There were enormous differences between the indoor group (0.34%) and the ecological group (0.80%). During the year, the most impressive variations were registered for the cholesterol-raising palmitic acid. The benefits for the consumer: low content of cholesterol-raising fatty acids, high content of cholesterol-lowering fatty acids and high percentage of anticarcinogenic fatty acids, cannot be realized by one system of farm management.     

全球氨基酸市场供需与预测

概述了近年来饲料添加剂用氨基酸类的现状和今后发展。着重介绍了氨基酸中主要产品蛋氨酸、赖氨酸和苏氨酸在美国、欧盟和日本的生产和市场发展动向。由于这类食品添加剂需求强劲，目前，该市场正处在回升之中。     

酶对热反应红烧风味香精滋味的影响

为了探究酶对热反应红烧风味香精滋味的影响,采用高效液相色谱法分析猪肉酶解液中游离氨基酸的含量,并结合感官评价和电子舌分析技术对红烧风味香精进行了滋味鉴定,同时结合电子鼻分析香精的气味轮廓。结果表明,制备红烧风味香精的最优酶复配方式为:加酶量0.3%〔m(木瓜蛋白酶)∶m(风味酶)∶m(菠萝蛋白酶)=2∶3∶1〕(以瘦肉质量为基准)。最优酶复配方式对应的酶解液中,苦味氨基酸含量最多,为29.32 g/L,其次为鲜味氨基酸,含量为10.21 g/L。对于不同酶复配比例下制备的热反应香精样品,通过电子鼻和感官评价数据的主成分分析可以进行较好地区分,而通过电子舌分析的区分效果则不理想。     

大孔PVC树脂负载H3SiW12O40催化剂的酸性研究

以大孔PVC树脂为载体．负载Keggin型杂多酸H3SiW12O40经过处理后得到了一种新型的杂多酸催化剂。本文采用电化学分析法测定负载杂多酸催化剂的总酸量及强、中、弱三种不同强度酸位的酸量,用吡啶-红外光谱测定出Bronsted酸和Lewis酸的比例．从而得出催化剂中Bronsted酸和Lewis酸的酸量及不同酸位的酸类型。     

鲩鱼脂肪酸的组成及其含量的GC-MS分析

采用气相色谱-质谱法分析了鲩鱼中脂肪酸的化学组成及各成分的含量。鲩鱼中的脂肪经石油醚提取、酸碱结合法甲酯化、GC-MS测定、总离子流图峰面积归一化法测定各组分相对含量。鲩鱼中检出26种脂肪酸,其中饱和脂肪酸含量为38.46%,不饱和脂肪酸61.54%。,含量较高的脂肪酸是亚麻油酸31.83%,油酸29.89%,棕榈油酸11.36%。     

冷杉针叶三萜酸对番茄生长及产量和品质的影响

以番茄品种"迪芬尼"为试材,研究了冷杉针叶三萜酸对番茄生长及产量和品质的影响。初步结果表明:施用冷杉针叶三萜酸可以有效促进番茄植株的生长势,增加植株茎粗,提高番茄坐果率,番茄产量比清水对照增产8.7%,还可提高番茄果实中干物质、维生素C、可溶性蛋白和可溶性糖含量,降低果实中可滴定酸含量,而且与嘧菌·百菌清混合使用有增效作用。