HPLC同时测定花果茶中3种成分的含量

目的建立同时测定花果茶中3种指标性成分的含量的HPLC方法。方法色谱柱为Welchrom C_(18)(4.6mm×250 mm,5μm);甲醇-乙腈-0.1%磷酸水溶液为流动相梯度洗脱,检测波长为280 nm,柱温为30℃,流速为1.0 ml/min。结果绿原酸、儿茶素、表儿茶素分别在0.0940～0.9400 mg (r=1.0000),0.5000～5.0000 mg(r=0.9996),0.2426～2.4260 mg (r=0.9995)范围内线性关系良好,平均回收率分别为99.93%,100.19%,100.26%。结论建立的方法准确度高,重复性好,可用于花果茶的质量控制。     

反相高效液相色谱法测定东方草莓中儿茶素的含量

建立东方草莓中(+)-儿茶素的含量测定方法。采用Agilent ZORBAX SB-C18色谱柱(4.6mm×150mm,5μm)分离;以乙腈-0.1%磷酸水为流动相进行梯度洗脱,流速为1mL/min,检测波长为280nm,对10批东方草莓中的(+)-儿茶素进行了含量测定。结果表明:(+)-儿茶素的保留时间为14.543min,其线性范围为0.0512~0.6400μg(R2=0.9999);加样回收率为99.70%(RSD 2.67%)。所建方法操作简单,稳定可靠,可用于东方草莓的质量评价。     

RP-HPLC法测定猕猴桃根中儿茶素和表儿茶素含量

建立用反相高效液相色谱法(reversed-phase high performance liquid chromatography,RP-HPLC)测定猕猴桃根中儿茶素和表儿茶素含量的方法,并分析不同采挖季节猕猴桃根中儿茶素和表儿茶素含量的变化。采用Agilent TCC18(250 mm×4.6 mm,5μm)色谱柱,以乙腈-1%乙酸水溶液为流动相,以1.0 m L/min的流速梯度洗脱,检测波长280 nm,柱温30℃,进样量10μL。结果显示,儿茶素和表儿茶素的浓度线性范围分别为1.0μg/m L~198.6μg/m L(r2=0.999 9)和1.0μg/m L~201.0μg/m L(r2=0.999 9),儿茶素平均加样回收率为99.16%,相对标准偏差(relative standard deviation,RSD)为0.66%(n=9),表儿茶素平均加样回收率为100.99%,RSD为0.74%(n=9)。本法适用于猕猴桃根中儿茶素和表儿茶素的精确定量,检测结果表明,初春采收的猕猴桃根中的儿茶素和表儿茶素含量明显高于秋冬。     

HPLC法测定苹果浓缩汁中的多酚类物质

利用高效液相色谱法(HPLC)分析了儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸、阿魏酸等六种酚类物质在鲁加1号和鲁加5号苹果浓缩汁中的的含量.色谱条件:色谱柱为EdipseXDB-C18色谱柱(150mm×4.6mm id,5μm),以甲醇-1%乙酸水溶液作为流动相进行梯度洗脱.柱温30℃,流速为1.0ml/min,检测波长为280nm.在此色谱条件下,各组分均得到很好的分离.经测定鲁加1号苹果浓缩汁中含有儿茶素、绿原酸、咖啡酸、表儿茶素、香豆酸、阿魏酸等六种酚类物质;鲁加5号苹果浓缩汁中含有较少的绿原酸、咖啡酸、表儿茶素、香豆酸、阿魏酸等五种酚类物质.     

高效液相色谱法测定叔丁基对苯二酚含量的方法学研究

建立了HPLC叔丁基对苯二酚含量的方法:色谱柱:Shim-pack Vp-ODS(150mm×4.6 mm,5μm)接Cl8保护柱(20mm×4.6mm,5μm);以乙腈∶水=32∶ 68(V/V,含1%乙酸)作为流动相;流速:0.8mL/min;检测波长:290nm;柱温:25℃.结果表明TBHQ浓度在2×10-4～1.0mg/mL范围内与峰面积线性关系良好r≥0.9999,最低检测限为4ng,并建立了回收率及日内和日见精密度实验.     

HPLC法测定黑豆皮中原儿茶酸、表儿茶素的含量

建立HPLC波长切换法同时测定黑豆皮中原儿茶酸、表儿茶素含量的方法。固定相为shim-pack VP-ODS C18(250 mm×4.6 mm,5μm),流动相为乙腈-0.1%磷酸溶液,流速为1.0 m L/min,检测波长为260、280 nm,柱温35℃。原儿茶酸、表儿茶素分别在0.010 52 mg/m L~1.052 mg/m L(r=0.999 6)和0.012 24 mg/m L~1.224 mg/m L(r=0.998 9)浓度范围内与峰面积呈良好的线性关系,平均回收率分别为99.46%(RSD=1.08%,n=6)和99.06%(RSD=1.02%,n=6)。     

高效液相色谱法同时测定发酵前后白参菌茶中六种活性成分

以绿茶和绿茶与白参菌共发酵茶为研究对象,建立快速同时检测绿茶与白参菌共发酵前后茶叶中的6种活性成分含量变化的高效液相色谱检测方法。将白参菌与绿茶共发酵,制备白参菌发酵茶。采用Wonda Sil C18柱(4. 6 mm×250 mm,5μm),乙腈(A)-0. 2%H3PO4溶液(B)为流动相,梯度洗脱(0～15 min,5%A→15%A; 15～40 min,15%A→25%A; 40～45 min,25%A→5%A),流速1 m L/min,柱温30℃,检测波长为280 nm检测茶叶发酵前后的活性成分含量。结果表明,绿茶经过与白参菌共发酵后,咖啡碱和可可碱含量几乎没有变化,表没食子儿茶素、表儿茶素、表没食子儿茶素没食子酸酯、表儿茶素没食子酸酯的含量均大幅下降。6种活性成分在6. 25～2 000μg/m L下线性关系良好,相关系数(R)在0. 995 5～0. 999 9,检出限在0. 312 5～1. 870μg/m L,绿茶的加标回收率在95. 06%～111. 06%,白参菌茶的加标回收率在85. 06%～118. 88%。白参菌与绿茶共发酵前后化学成分的含量发生变化,该液相检测方法快速、准确、重现性好,能够满足白参菌茶中多种活性成分同时定性、定量检测需求,具有一定的应用价值。     

HPLC同时测定橄榄油中4种多酚类化合物的含量

建立了HPLC同时测定橄榄油中没食子酸、羟基酪醇、儿茶素和阿魏酸4种多酚类化合物含量的方法。橄榄油先经正己烷溶解,再用60%甲醇两次提取其中的多酚类化合物。色谱条件为ZORBAX SB-C18反相色谱柱(150 mm×4.6 mm,5.0μm);以0.5%乙酸(A)+甲醇(B)+异丙醇(C)为流动相;梯度洗脱顺序为0~14 min,95%~92%A,2.5%~4%B,2.5%~4%C;14~30 min,92%~82%A,4%~9%B,4%~9%C;柱温35℃;流速1.0 m L/min;进样量20μL;DAD检测器波长280 nm。结果表明:在此色谱条件下,4种多酚类化合物在30 min内能较好地分离,且测定结果的重复性好(RSD≤1.890%),精密度高(RSD≤0.023%),加标回收率在82.4%~97.6%之间。该方法能准确地同时测定橄榄油中4种多酚类化合物的含量。     

HPLC法同时测定白刺果实中8种黄酮成分的含量

建立同时测定白刺果中没食子酸、儿茶素、杨梅素、芦丁、槲皮素、木犀草素、山奈酚和异鼠李素8种黄酮化合物含量的HPLC的方法。采用HYPERSIR C18色谱柱(250 mm×4.6 mm,5μm),柱温35℃,以甲醇-0.1%甲酸水溶液为流动相,进行梯度洗脱,双波长检测(λ1=270 nm,λ2=370 nm),进样量10μL,流速0.8 m L/min。结果:在0~125μg/m L内8种黄酮均有良好的线性关系(R2≥0.999 0),没食子酸、儿茶素、杨梅素、芦丁、槲皮素、木犀草素和山奈酚的平均回收率分别为98.42%,99.19%,90.65%,102.32%,96.51%,98.70%和93.68%,最低检出限依次为0.032,0.052,0.074,0.038,0.059,0.043,0.021和0.036 mg/L。方法精密度RSD≤2.21%(n=6),在此条件下,测得白刺果实中没食子酸、儿茶素、杨梅素、芦丁、槲皮素、木犀草素和山奈酚含量为0.031,0.057,0.064,0.068,0.016和0.038 mg/g。该方法快速简单,重现性好,可为白刺果实质量控制提供定量分析方法。     

HPLC法测定不同产地黑豆皮中表儿茶素的含量

建立黑豆皮中表儿茶素的含量测定方法,测定5个不同产地黑豆皮中表儿茶素的含量。采用HPLC法测定黑豆皮中表儿茶素的含量,色谱柱:Phenomenex Luna Su C18柱(250×4.60 mm,5μm);流动相:A相为体积比为1.0%磷酸水溶液,B相为乙腈∶水(体积比为80∶20),进行梯度洗脱;流速:1.0 mL/min;检测波长:280 nm;柱温:30℃;进样量:10μL。结果得出,表儿茶素标准曲线回归方程为:Y=6×106X-14 292(r=0.999 8),在0.154 95μg~1.549 5μg范围内线性关系良好,平均回收率分别为96.7%、100.2%、103.9%,不同产地黑豆皮中表儿茶素含量范围为1.27 mg/g～4.18 mg/g。所用方法简便、准确,可用于不同产地黑豆皮的质量控制。     

Reliable identification of grapevine rootstock varieties using RAPD PCR on woody samples

Since grapevine ( Vitis spp .) rootstock material is being traded increasingly as disbudded woody material a lack of distinctive morphological features on such material necessitates an alternative and reliable means of identification. Methods described here were developed for rapid and efficient extraction of DNA from woody samples rich in phenolic compounds and polysaccharides, and for subsequent identification of varieties by RAPD PCR. Using these methods, and with the application of only one selected RAPD primer, we were able to differentiate sixteen rootstock varieties, including the seven varieties most commonly used in Germany. Problems commonly encountered with reproducibility of RAPD patterns were avoided by choosing primers with a dinucleotide sequence and a high G/C content that allowed a rather high annealing temperature of 45°C. Methods described here should also be useful for other horticultural crops, especially those with woody tissues rich in phenolic compounds and polysaccharides.     

Chlorohydrins of bisphenol A diglycidyl ether (BADGE) and of bisphenol F diglycidyl ether (BFDGE) in canned foods and ready-to-drink coffees from the Japanese market

BADGE.2HCl and BFDGE.2HCl were determined in 28 samples of ready-to-drink canned coffee and 18 samples of canned vegetables (10 corn, 5 tomatoes and 3 others), all from the Japanese market. HPLC was used as the principal analytical method and GCMS for confirmation of relevant LC fractions. BADGE.2HCl was found to be present in one canned coffee and five samples of corn, BFDGE.2HCl in four samples of canned tomatoes and in one canned corn. No sample was found which exceeded the 1mg/kg limit of the EU for the BADGE chlorohydrins. However the highest concentration was found for the sum of BFDGE.2HCl and BFDGE.HCl.H₂O at a level of 1.5mg/kg. A Beilstein test confirmed that all cans containing foods contaminated with BADGE.2HCl or BFDGE.2HCl had at lest one part coated with a PVC organosol.     

Aroma characterization of various apricot varieties using headspace–solid phase microextraction combined with gas chromatography–mass spectrometry and gas chromatography–olfactometry

The characterization of the aromatic profile of several apricot cultivars with molecular tracers in order to obtain objective data concerning the aromatic quality of this fruit was undertaken using headspace–solid phase microextraction (HS–SPME). Six apricot cultivars were selected according to their organoleptic characteristics: Iranien, Orangered, Goldrich, Hargrand, Rouge du Roussillon and A4025. The aromatic intensity of these varieties measured by HS–SPME–Olfactometry were defined and classified according to the presence and the intensity of grassy, fruity and apricot like notes. In the six varieties, 23 common volatile compounds were identified by HS–SPME–GC–MS. Finally, 10 compounds, ethyl acetate, hexyl acetate, limonene, β-cyclocitral, γ-decalactone, 6-methyl-5-hepten-2-one, linalool, β-ionone, menthone and (E)-hexen-2-al were recognized by HS–SPME–GC–O as responsible of the aromatic notes involved in apricot aroma and considered as molecular tracers of apricot aromatic quality which could be utilized to discriminate apricot varieties.     

European priorities for research to support legislation in the area of food contact materials and articles

A strong science base is required to underpin the planning and decision-making process involved in determining future European community legislation on materials and articles in contact with food. Significant progress has been made in the past 5 years in European funded work in this area, with many developments contributing to a much better understanding of the migration process, and better and simpler approaches to food control. In this paper this progress is reviewed against previously identified work-areas (identified in 1994) and conclusions are reached about future requirements for R&D to support legislation on food contact materials and articles over the next 5 or so years.     

Textural Properties of Cold-set Gels Induced from Heat-denatured Whey Protein Isolates

A 9% whey protein (WP) isolate solution at pH 7.0 was heat-denatured at 80°C for 30 min. Size-exclusion HPLC showed that native WP formed soluble aggregates after heat-treatment. Additions of CaCl2 (10–40 mM), NaCl (50–400 mM) or glucono-delta-lactone (GDL, 0.4–2.0%, w/v) or hydrolysis by a protease from Bacillus licheniformis caused gelation of the denatured solution at 45°C. Textural parameters, hardness, adhesiveness, and cohesiveness of the gels so formed changed markedly with concentration of added salts or pH by added GDL. Maximum gel hardness occurred at 200 mM NaCl or pH 4.7. Increasing CaCl2 concentration continuously increased gel hardness. Generally, GDL-induced gels were harder than salt-induced gels, and much harder than the protease-induced gel.     

Tests of potential functional barriers for laminated multilayer food packages. Part I: Low molecular weight permeants

The advent of the functional barrier concept in food packaging has brought with it a requirement for fast tests of permeation through potential barrier materials. In such tests it would be convenient for both foodstuffs and materials below the functional barrier (sub-barrier materials) to be represented by standard simulants. By means of inverse gas chromatography, liquid paraffin spiked with appropriate permeants was considered as a potential simulant of sub-barrier materials based on polypropylene (PP) or similar polyolefins. Experiments were performed to characterize the kinetics of the permeation of low molecular weight model permeants (octene, toluene and isopropanol) from liquid paraffin, through a surrogate potential functional barrier (25 μm-thick oriented PP) into the food simulants olive oil and 3% (w/v) acetic acid. These permeation results were interpreted in terms of three permeation kinetic models regarding the solubility of a particular model permeant in the post-barrier medium (i.e. the food simulant). The results obtained justify the development and evaluation of liquid sub-barrier simulants that would allow flexible yet rigorous testing of new laminated multilayer packaging materials.     

Occurrence of bisphenol-F-diglycidyl ether (BFDGE) in fish canned in oil

The levels of bisphenol-F-diglycidyl ether (BFDGE) were quantified as part of a European survey on the migration of residues of epoxy resins into oil from canned fish. The contents of BFDGE in cans, lids and fish collected from all 15 Member States of the European Union and Switzerland were analysed in 382 samples. Cans and lids were separately extracted with acetonitrile. The extraction from fish was carried out with hexane followed by re-extraction with acetonitrile. The analysis was performed by reverse phase HPL C with fluorescence detection. BFDGE could be detected in 12% of the fish, 24% of the cans and 18% of the lids. Only 3% of the fish contained BFDGE in concentrations considerably above 1mg/kg. In addition to the presented data, a comparison was made with the levels of BADGE (bisphenol-A-diglycidyl ether)analysed in the same products in the context of a previous study.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

Influence des ions sur le pouvoir hydratant de l'ure e: e tude sur peau de porc ex vivo

This study deals with the influence of ions (NaCl and MgSO4) in a W/O emulsion containing 10% urea. Moisturization kinetics are assessed by corneometry on pig skin ex vivo. The formula's influence on urea penetration is measured by infrared spectrometry with an ATR device and the stripping method. Corneometry and spectroscopy were chosen to record simultaneously the hydratation levels and urea localization into superficial cell layers. Urea crystallization after evaporation of emulsions and aqueous solutions is described. Results show that urea does not hydrate nor penetrate when applied to the skin through an aqueous gel. In a W/O emulsion, sodium chloride increases the ability of urea to moisturize without improving penetration. In vitro urea crystallization is disturbed by sodium chloride or magnesium sulphate for solutions and emulsions. This stabilization by ions is correlated with good moisturization values. The stabilization of urea in the solute state provided by ions increases its water epidermal binding capacity without enhancing penetration.