气相色谱法测定乙酯型鱼油微胶囊产品中EPA乙酯和DHA乙酯含量

建立了气相色谱法测定乙酯型鱼油微胶囊产品中EPA乙酯和DHA乙酯含量的方法。样品经盐酸溶液溶解、破壁,再经异辛烷萃取净化,采用气相色谱法分析测定,内标法定量(二十三烷酸甲酯为内标)。结果表明:EPA乙酯和DHA乙酯含量在150~3 000μg/m L范围内,该方法的线性关系良好,相关系数分别为0.999 6和0.999 8,EPA乙酯和DHA乙酯最低检出限分别为8.8、16.5μg/m L;加标回收率分别为98.5%~99.0%、98.2%~100.5%,相对标准偏差(RSD)分别小于等于0.7%、0.9%。该方法分析时间短,重现性好,灵敏度高,可用于乙酯型鱼油微胶囊产品中EPA乙酯和DHA乙酯含量的测定。

乙酯型金枪鱼油不同级分子蒸馏过程中脂肪酸含量及挥发性物质变化

乙酯型金枪鱼油是粗鱼油经过多级分子蒸馏后得到的富含多不饱和脂肪酸,无色无味的优质鱼油,在这个过程中发生了一系列变化。利用气相色谱-质谱联用仪、电子鼻、傅里叶变换红外光谱仪检测不同蒸馏组分的金枪鱼油在成分、风味和性质上的变化以及主要的挥发性物质。结果表明:原料鱼油和不同蒸馏组分鱼油中二十二碳六烯酸(docosahexaenoic acid,DHA)和二十碳五烯酸(eicosapentaenoic acid,EPA)的含量呈先增加后下降趋势,其中EPA含量可达31.41%,DHA含量可达74.10%;二级分子蒸馏可以得到DHA、EPA总含量高达84.26%的乙酯型鱼油,而三级、四级、五级蒸馏鱼油中DHA和EPA含量显著下降。电子鼻检测原料鱼油及不同蒸馏组分的鱼油挥发性物质差异显著。不同蒸馏组分的金枪鱼油主体风味物质为己醛、辛醛、庚醛、壬醛、1-辛烯-3-醇、2-十一酮、2-戊基呋喃等,共同赋予其鱼腥、油脂气息、泥土味、脂肪香味、青草味、蘑菇香、蔬菜香味等。红外光谱分析说明了不同级分子蒸馏后得到的金枪鱼油的主要成分含量是有所不同的。不同蒸馏组分的鱼油中一级、二级鱼油脂类成分种类最多,富集效果最好,而三级、四级、五级分子蒸馏富集效果显著下降。

乙酯型鱼油对小鼠骨性关节炎的改善作用

目的:研究乙酯型鱼油(fish oil,FO)对骨性关节炎小鼠软骨退变的改善作用。方法:9周龄雄性C57BL/6J小鼠构建内侧半月板不稳骨性关节炎模型。术后8周,随机分成假手术组、模型对照组、阳性对照组和FO低、高剂量组。每天灌胃1次,持续灌胃60d后,取关节软骨组织行苏木精-伊红染色、甲苯胺蓝染色及实时荧光定量聚合酶链式反应(quantitative real-time polymerase chain reaction,qPCR)分析。结果:苏木精-伊红和甲苯胺蓝染色分析表明FO能够显著改善软骨结构,维持软骨基质的稳定。qPCR结果表明,FO能显著提高Acan、Col2α1的mRNA表达,维持软骨细胞正常表型;抑制Col10α1、Runx-2、Bcl-2、Bax和Caspase-3的表达,抑制软骨细胞的肥大分化及异常凋亡。同时,FO能够显著降低mTOR的mRNA表达,提高LC-3B和ATG-5的mRNA表达,促进自噬进程,维持软骨的稳态。结论:FO能够通过激活软骨细胞自噬进程来抑制骨性关节炎小鼠的软骨退变进程。

乙酯型鱼油对鱼糜制品理化特性和风味的影响

乙酯型鱼油主要通过增强蛋白间疏水作用力增强凝胶强度,并有利于二硫键的形成,而对内源性转谷氨酰胺酶(TGase)不起作用。为确定乙酯型鱼油添加量对鱼糜凝胶品质的影响,测定凝胶强度、质构特性、白度、持水和挥发性风味等指标,通过蛋白分子间作用力和凝胶电泳方法测定添加效果并分析其作用机理。结果表明:乙酯型鱼油添加量为1.2%时凝胶强度达到最大值,具有较高的质构特性,然而导致白度降低。随着乙酯型鱼油添加量的增加,热处理过程中不饱和脂肪酸损失量也会增加。气相色谱-质谱结果表明:乙酯型鱼油会增加鱼糜凝胶的腥味成分,尚在可接受范围。红外光谱结果表明:乙酯型鱼油对鱼糜凝胶蛋白结构无影响。经综合比较,乙酯型鱼油添加量为1.2%时鱼糜凝胶品质得到改善。本研究结果为提高鱼糜制品品质及生产研发提供理论依据。

亚临界水中乙酯型鱼油水解工艺的响应面优化

亚临界水作介质进行乙酯型鱼油的水解试验,考察反应温度、反应时间和水油体积比对水解率的影响。在此基础上,采用Box-Benhnken设计法和响应面分析法优化其水解工艺,建立其水解二次多项数学模型与验证其可靠性。同时,探讨该3个因素交互作用和较适水解条件,并对其进行验证。结果显示,影响乙酯型鱼油水解工艺的因素主次顺序:反应温度>水油体积比>反应时间,其较适水解工艺参数为反应温度339℃,反应时间16 min,水油体积比3.9。在此条件下,水解率实测值为(88.42±0.17)%,与模型预测值88.44%接近。

磷脂型DHA的消化、吸收与转运

二十二碳六烯酸(DHA)参与大脑生长发育,影响大脑中神经递质、突触可塑性以及信号转导等生理功能。目前,市售DHA膳食补充剂产品较多,其脂质结构主要分为甘油三酯型DHA(TAG-DHA)、乙酯型DHA(EE-DHA)和磷脂型DHA(PL-DHA)。DHA不同酯化结构影响其吸收、转运和生物利用度。目前PL-DHA和TAG-DHA生物利用度高仍存在争议,而大部分的研究证明PL-DHA是最佳的DHA吸收形式,尤其是能被脑组织更好地吸收。本文比较分析磷脂型DHA与其它形式DHA的吸收、转运等,总结不同模型中磷脂型或甘油三酯型DHA在人体或动物体内生物利用度。目前大多是动物实验研究,还需更深入的人体试验,来探究PL-DHA在人体的吸收过程及其机理,评价其生物利用度以及对神经发育的长期作用。PL-DHA有望成为一种更高效的DHA食品营养强化剂,添加到婴儿配方奶粉中或制成胶囊服用。

高n-3多不饱和脂肪酸甘油酯型鱼油的制备工艺

以二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)质量分数分别为25.17%和15.34%的乙酯型鱼油为初始原料,首先通过分子蒸馏技术获得EPA和DHA总质量分数在70%以上的乙酯型鱼油,考察蒸馏温度对鱼油中EPA和DHA质量分数及比值(EPA/DHA值)的影响.发现当分子蒸馏原料中EPA和DHA总质量分数较低时(如40.51%),分子蒸馏可实现n-3多不饱和脂肪酸的富集;对于EPA和DHA总质量分数高于70%的乙酯型鱼油,分子蒸馏的作用以调节EPA/DHA值为主,且EPA/DHA值与分子蒸馏温度(90~130℃)呈现较好的线性关系.随后,对EPA和DHA总质量分数在70%以上的乙酯型鱼油进行尿素包合处理,发现尿素包合技术可进一步增加高含量乙酯型鱼油中EPA和DHA的质量分数(至80.82%~91.61%),但对EPA/DHA值影响较小.最后通过酶促甘油解方法将联合使用分子蒸馏、尿素包合技术得到的一系列高含量乙酯型鱼油转变为甘油酯型.

不同类型鱼油对维生素A醋酸酯稳定性的影响

目的通过添加不同类型鱼油,分析保健品中维生素A醋酸酯的降解情况。方法将配制好的鱼油样品在温度(37±2)℃,相对湿度(75±5)%的条件下放置6个月,分别在0、1、2、3、6个月取样,检测维生素A醋酸酯的含量。将检测结果与0个月比较,考察维生素A醋酸酯含量的变化。结果通过6个月的考察分析,乙酯型鱼油维生素A醋酸酯含量变化较大,甘油三酯型鱼油维生素A醋酸酯变化小,且乙酯型鱼油配方样品中维生素A醋酸酯的降解产物较杂。结论鱼油保健品在加速实验条件下放置6个月,不同结构的鱼油对维生素A醋酸酯含量的影响不同,甘油三酯型鱼油更稳定。

基于电子鼻和气质联用技术分析鱼油挥发性成分

鱼油的酸败往往伴随着气味的变化,本研究利用电子鼻结合顶空固相微萃取-气质联用技术对乙酯型鱼油的挥发性成分进行分析,旨在探究鱼油挥发性物质与其品质的关系。运用电子鼻主成分分析(PCA)和线性判别分析(LDA)区分不同储藏时间的样品,通过偏最小二乘法(PLS)建立酸价和过氧化值的预测模型,通过HS-SPME-GC-MS分析鉴定储藏鱼油挥发性物质。结果表明LDA分析方法对不同储藏时间的乙酯型鱼油样品区分程度明显优于PCA分析,电子鼻分析能够反映鱼油氧化酸败程度,可以识别区分不同储藏时间的鱼油样品;采用PLS偏最小二乘法(PLS)建立的酸价和过氧化值预测模拟方程具有良好线性关系,可作为酸价、过氧化值预测的一种辅助手段;通过HS-SPME-GC-MS检测出57种挥发性物质,多以醛类和酯类为主,其中2,4-庚二烯醛的含量最高,可作为鱼油产品质量优劣的指标。

响应面法优化精制沙丁鱼油EPA和DHA富集工艺

以乙酯型精制沙丁鱼油(EPA含量(15.41±0.13)%,DHA含量(8.00±0.03)%)为原料,在尿酯比、包合温度、醇尿比、包合时间4个单因素试验的基础上,采用响应面分析法优化尿素包合法富集工艺。结果表明:最优工艺条件为尿酯比3.5∶1、包合温度0℃、醇尿比2.6∶1、包合时间1.2h,此条件下,产物中EPA+DHA含量为(78.12±0.12)%(EPA含量(53.35±0.10)%;DHA含量(24.77±0.02)%),与理论值78.17%基本一致。

Identification and Analysis of Mature Plant Type Mutants of M_1 Generation Foxtail Millet Changnong35 Treated with EMS Mutagenesis

[Objective] The aim was to identify the mutants of millet Changnong35 induced by different concentrations of EMS, so as to construct a millet mutant library. [Method] Foxtail millet cultivar Changnong35 which is widely used in agricultural production, was treated with 0.8% and 1.0% EMS; and then seven traits of mutants were investigated analyzed, to classify the mutants into different groups. [Result] 282 mutants in the M1 generation related to plant type were obtained, of which, 100 mutant plants treated with 0.8% EMS can be divided into 10 groups; 182 mutant plants obtained by using 1.0% EMS can be divided into 17 groups. The analysis results of the mature plant type traits of the M1 Generation showed that, plant height, diameter of stem under spike, diameter of the first internode under spike and internode number of the mutants treated with 1.0% EMS were significantly different from those of control, while those of mutants treated with 0.8% EMS did not show significant difference from those of control. [Conclusion] The inducing with 1.0% EMS was more conducive to obtain a large number and different types of mutants from Changnong35.

Treatment strategies using adefovir dipivoxil for individuals with lamivudine-resistant chronic hepatitis B

AIM:To investigate retrospectively the long-term efficacy of various treatment strategies using adefovir dipivoxil(adefovir) in patients with lamivudine-resistant chronic hepatitis B.METHODS:We included 154 consecutive patients in two treatment groups:the "add-on" group(n = 79),in which adefovir was added to ongoing lamivudine treatment due to lamivudine resistance,and the "switch/combination" group(n = 75),in which lamivudine was first switched to adefovir and then re-added later as needed.The "switch/combination" group was then divided into two subgroups depending on whether participants followed(group A,n = 30) or violated(group B,n = 45) a proposed treatment strategy that determined whether to add lamivudine based on the serum hepatitis B virus(HBV) DNA levels(< 60 IU/mL or not) after 6 mo of treatment(roadmap concept).RESULTS:The cumulative probability of virologic response(HBV DNA < 60 IU/mL) was higher in group A than in the "add-on" group and in group B(P < 0.001).In contrast,the cumulative probability of virologic breakthrough was lower in the "add-on" group than in group B(P = 0.002).Furthermore,the risk of virologic breakthrough in the multivariate analysis was significantly lower in the "add-on" group than in group A(hazard ratio = 0.096;95%CI,0.015-0.629;P = 0.015).CONCLUSION:The selective combination of adefovir with lamivudine based upon early treatment responses increased the odds of virologic breakthrough relative to the use of uniform combination therapy from the beginning of treatment.

Efficacy compared between entecavir and adefovir dipivoxil on HBeAg-positive nucleos(t)ide-naive patients with chronic hepatitis B at week 12 and week 48

Objective:To evaluate the efficacy of entecavir and adefovir dipivoxil on HBeAg-positive nucleos(t)ide-naive patients with chronic hepatitis B with the method of Meta analysis.Methods:We searched PUBMED,EMBASE,CNKI (China National Knowledge Infrastructure),the Cochrane Central Register of Controlled Trials and the Cochrane Database of Systematic Reviews with reference to all data documented before May 2010.The dosage of entecavir and adefovir dipivoxil was 0.5 mg/d and 10 mg/d,respectively.Heterogeneity was examined by Chi-square test,the relative risk calculated and forest plot drawn.Rates of undetected serum HBV DNA,serum alanine aminotransferase (ALT) normalization,HBeAg clearance,HBeAg seroconversion and adverse effect occurrence were analyzed.Results:Six articles were included,which fit well in with this study.Meta analysis showed that the rate of undetected serum HBV DNA(P=0.000 2 at week 12,P=0.002 at week 48)and that of serum ALT normalization(P=0.04 at week 12,P=0.008 at week 48)in the entecavir group were higher than those in the adefovir dipivoxil group.However,no statistic significance existed between the two groups in the rate of HBeAg clearance (P=0.17),the rate of HBeAg seroconversion(P=0.53)or the rate of adverse effect occurrence(P=0.92)at week 48.Conclusion:Entecavir was superior to adefovir dipivoxil in decreasing serum HBV DNA and normalizing serum ALT in the HBeAg-positive nucleos(t)ide-naive patients with chronic hepatitis B.

Kinetics of Glucose Ethanolysis Catalyzed by Extremely Low Sulfuric Acid in Ethanol Medium

The kinetics for production of ethyl levulinate from glucose in ethanol medium was investigated. The experiments were performed in various temperatures （433-473 K） and initial glucose concentrations （0.056-0.168 mol·L-1） with extremely low sulfuric acid as the catalyst. The results show that higher temperature can improve the conversion of glucose to ethyl levulinate, with higher yield of ethyl levulinate （44.79%, by mole） obtained at 473 K for 210 min. The kinetics follows a simplified first-order kinetic model. For the main and side reactions, the values of activation energy are 122.64 and 70.97 kJ·mo1-1, and the reaction orders are 0.985 and 0.998, respectively.

Reactive Distillation for Producing n-Butyl Acetate:Experiment and Simulation

In this paper, a reactive distillation (RD) column was applied for synthesis n-butyl acetate from n-butanol and acetic acid. The Langmuir-Hinshelwood-Hougen-Watson (LHHW) kinetic model and an equilibrium stage model for separation were employed to study the RD process. The results obtained from the equilibrium stage model agreed well with the experiments. The effects of operating variables on the n-butanol conversion and n-butyl acetate purity were further investigated. The optimal column configuration for the production of n-butyl acetate was designed with 5 rectifying stages, 8 reaction stages and 13 stripping stages by the simulation study. According to the simulation results, n-butanol conversion and n-butyl acetate purity all reached greater than 96%.

Preparation,Characterization of Dawson-type Heteropoly Acid Cerium（Ⅲ） Salt and Its Catalytic Performance on the Synthesis of n-Butyl Acetate

A novel cerium(Ⅲ) salt of Dawson type tungstophosphoric acid(Ce2P2W18O62·16H2O) was prepared by doping cerous nitrate in H6P2W18O62·13H2O powder and characterized by thermogravimetry and differential thermal analyses(TG/DTA),Fourier transform infrared spectroscopy(FT-IR),X-ray powder diffraction(XRD),pyridine infrared spectroscopy(Py-IR) and scanning electron microscopy(SEM).Its catalytic activity was evaluated by the probe reaction of synthesis of n-butyl acetate with acetic acid and n-butanol.The effects of various parameters such as molar ratio of n-butanol to acetic acid,reaction temperature,reaction time,and catalyst amount have been studied by single factor experiment.The results show that Ce2P2W18O62·16H2O behaved as an excellent heterogeneous catalyst in the synthesis of n-butyl acetate.The optimum synthetic conditions were determined as follows︰molar ratio of n-butanol to acetic acid at 2.0︰1.0,mass of the catalyst being 1.44% of the total reaction mixture,reaction temperature of 120 ℃ and reaction time of 150 min.Under above conditions,the conversion of acetic acid was above 97.8%.The selectivity of n-butyl acetate based on acetic acid was,in all cases,nearly 100%.The catalysts could be recycled and still exhibited high catalytic activity with 90.4% conversion after five cycles of reaction.It was found by means of TG-DTA and Py-IR that the catalyst deactivation was due to the adsorption of a complex of by-product on the active sites on catalysts surface or the catalyst loss in its separation from the products.Compared with using sulfuric acid as catalyst,the present procedure with Ce2P2W18O62·16H2O is a green productive technology due to simple process,higher yield,catalyst recycling and no corrosion for the production facilities.

Bioavailability Improvement of SLMs Based Erythromycin Ethyl Succinate using Stearic Acid-Myrj-52-based SLM＇s

Solid lipid microparticles of erythromycin ethyl succinate were prepared using solvent evaporation method to improve its bioavailability and efficacy. The solvent was allowed to evaporate after which the various entrapments were determined; the best entrapment was used in the in vivo studies to determine the bioavailability and efficacy. This study was done with albino mice. The best entrapment obtained was 83% with a loading capacity of 2.9% （Batch D） and was used in comparison with the unformulated drug to check for the in vivo efficacy. The results show higher efficacy with the formulated drug than with the pure drug both in vitro and in vivo. The in vitro test results were better despite that some enzymes which need to act on the solid lipid microparticles were not present in the in vitro assay and could lead to a reduction in the release of the drugs. In conclusion, there was improvement in efficacy, and hence bioavailability.

Measurement and correlation of solubility of trimethylolethane in different pure solvents and binary mixtures

The solubilities of trimethylolethane in butanol,methyl acetate,ethyl acetate as well as in mixed solvents of(methanol+ethyl acetate) and(ethanol+ethyl acetate) were measured with the gravimetric method in the temperature range from 283.15 K to 318.15 K under atmosphere pressure.The experiment results showed that the solubility of trimethylolethane increased with the temperature,or along with the concentration of methanol or ethanol in the solvents of(methanol+ethyl acetate) and(ethanol + ethyl acetate).In addition,the experiment values were correlated by the van't Hoff equation,Modi fied Apelblat Equation,λh Equation,CNIBS/R-K equation and Jouyban–Acree Model.The Modi fied Apelblat Equation provided the best fitting results of the solubility data of TME in the pure solvents while the CNIBS/R-K model showed the best estimation of the solubility in the binary solvent mixtures.Furthermore,the density functional theory(DFT) calculations showed that solubility in different solvents related to the strength of the interaction between the trimethylolethane and the solvent molecules.Finally,the standard molar enthalpy and molar entropy of trimethylolethane during the dissolving process was also calculated by Modi fied Apelblat equation in this work.

Study on Hydrolysis of Methyl Acetate in a Catalytic Distillation Column

A nonequilibrium stage model was used to simulate countercurrent multicomponent catalytic distillation processes for methyl acetate hydrolysis. Computations of stage efficiencies or height equivalent to a theoretical plate (HETP) were entirely avoided by this model. The consistency of simulated results and experimental data in conversions and concentration of each component along a column indicates that the model predicts the actual process well. The influences of operating parameters on hydrolytic conversions, such as feed molar ratios, feed locations, feed and reflux rates, heights of reactive and stripping sections, were analyzed adequately by simulating calculations. A good operating mode was then obtained, which is helpful to the development of a new process.

Isobaric Vapor-Liquid Equilibrium of Binary Systems： p-Xylene ＋ （Acetic Acid, Methyl Acetate and n-Propyl Acetate） and Methyl Acetate ＋ n-Propyl Acetate in an Acetic Acid Dehydration Process

The vapor-liquid equilibrium data of four binary systems (acetic acid +p-xylene, methyl acetate +n-propyl acetate, n-propyl acetate +p-xylene and methyl acetate +p-xylene) are measured at 101.33 kPa with Ellis equilibrium still, and then both the NRTL and UNIQUAC models are used in combination with the HOC model for correlating and estimating the vapor-liquid equilibrium of these four binary systems. The estimated binary VLE results using correlated parameters agree well with the measured data except the methyl acetate +p-xylene system which easily causes bumping and liquid rushing out of the sampling tap due to their dramatically different boiling points. The correlation results by NRTL and UNIQUAC models have little difference on the average absolute deviations of temperature and composition of vapor phase, and the results by NRTL model are slightly better than those by UNIQUAC model except for the methyl acetate +n-propyl acetate system, for which the latter gives more accurate correlations.