固相微萃取-气质联用法分析3种柚子皮的香气成分

采用固相微萃取结合气相色谱-质谱联用法对琯溪蜜柚、缤纷田园蜜柚和缤纷田园红心蜜柚的果皮香气成分进行分析。结果表明:吸附温度65℃,吸附时间45 min,样品量1.000 g,解吸时间2 min为最佳条件。选用此条件对3种柚子皮所提取的挥发性成分进行定性分析,并以面积归一化法定量计算各组分的相对含量。琯溪蜜柚皮共鉴定出43种化合物,其中含3-蒈烯17.361%,含α-蒎烯41.222%;缤纷田园蜜柚皮共鉴定出42种化合物,其中含3-蒈烯为16.533%,含罗勒烯为41.238%;缤纷田园红心蜜柚皮共鉴定出36种化合物,其中含柠檬烯45.857%,含β-月桂烯为20.065%。     

运用顶空固相微萃取技术分析宣威火腿中的挥发性化合物

采用固相微萃取结合气相色谱 /质谱分析方法对宣威火腿中的挥发性化合物进行了提取和分析。试验结果表明 ,固相微萃取的时间和温度影响提取挥发性化合物的效果 ,试验选取 60℃、60min为提取条件 ,萃取物经气谱 /质谱分析 ,共鉴定出 72种化合物 ,其中烃类 2 8种、醛类 7种、醇类 4种、酸类 10种、酯类 5种、酮类 3种、杂环化合物 14种、酚类 1种。     

浙江"玉环文旦柚"果皮挥发性化学成分分析

采用固相微萃取和同时蒸馏萃取并结合气-质联机分析,从浙江玉环文旦柚鲜果皮中共鉴定出55个挥发性化学组分.分析固相微萃取样品,共鉴定出36个化合物,总质量分数98.92%,其主要成分为柠檬烯59.57%、月桂烯31.83%、β-蒎烯3.39%、顺-β-罗勒烯1.19%、香桧烯0.83%、α-蒎烯0.70%、β-水芹烯0.42%、橙花醛0.10%.分析同时蒸馏萃取样品,共鉴定出49个化合物,总质量分数87.97%,其主要成分为柠檬烯50.17%、月桂烯27.06%、氧化芳樟醇1.49%、圆柚酮(诺卡酮)2.67%、顺-β-罗勒烯1.00%、β-蒎烯0.80%、瓦伦烯0.46%、橙花醛0.42%.     

自制中式硬质干酪风味物质的研究

利用顶空固相微萃取气质联用技术(SPME/GC-MS)对自制中式硬质干酪的挥发性风味物质进行分离鉴定。首先通过单因素实验确定了顶空固相微萃取最优萃取条件为:平衡时间35min,萃取时间40 min,萃取温度50℃。共检测出42种挥发性风味化合物,其中羧酸类、醇类、酮类、醛类、酯类、烃类、杂环类化合物等是主要风味物质。     

固相微萃取/气-质联用分析猴头菇挥发性风味成分

采用固相微萃取/气-质联用方法 (SPME-GC-MS)对干猴头菇中的挥发性风味成分进行分析。考察了固相微萃取温度、时间等萃取条件对总离子流图中总峰面积的影响。在优化的SPME条件下,共鉴定出干猴头菇中的挥发性成分71种。其中醛类化合物的种类最多,共16种,含量最高,近30%。另有酮类化合物14种,醇类化合物5种,羧酸类化合物6种,含硫化合物和含氮杂环化合物各3种,含氧化合物10种,酚类及烃类化合物共14种。在上述类型风味物质的共同作用下,猴头菇呈现出一种独特的芳香气味。     

顶空固相微萃取-气相色谱质谱-嗅闻法测定不同品牌红腐乳挥发性风味物质

采用顶空固相微萃取法,结合气质联用技术、气相色谱-嗅闻-质谱技术对不同品牌大块红腐乳的挥发性风味成分进行了分析及比较。在顶空固相微萃取条件优化的基础上,确定了最佳实验条件:2g样品置于20mL顶空瓶中,50℃下平衡30min,萃取时间40min。通过实验共鉴定出64种挥发性成分,其中酯类19种、萜烯类19种、醇类7种、醛类6种、酮类4种、烯烃类3种、酚类2种、杂环化合物2种、烃类2种。腐乳共有挥发性风味成分23种,其中乙醇、α-水芹烯、乙酸乙酯、丁酸乙酯、辛酸乙酯、2-戊基呋喃和茴香脑为主要挥发性风味物质。     

鲜榨锦橙汁香气成分的固相微萃取-气质联用分析

采用固相微萃取-气质联用法对鲜榨锦橙汁的香气成分进行分析,并比较不同萃取头对鲜榨橙汁香气成分的萃取差异。结果表明:从鲜榨橙汁中共鉴定出53种香气成分,包括烯烃类、酯类、醇类、醛类和酮类,其中的主要香气化合物为柠檬烯、β-月桂烯、芳樟醇、α-松油醇、4-松油烯醇、丁酸乙酯、辛醛、α-蒎烯、β-水芹烯等物质。     

脯氨酸反应物挥发性成分固相微萃取条件优化

对脯氨酸美拉德反应物挥发性成分进行顶空-固相微萃取条件的优化(采用65μm聚二甲基硅氧烷/二乙烯基苯固相微萃取头),确定其最优纤维头长度、萃取温度、时间条件,应用气相质谱检测分析其挥发性成分。结果表明,固相微萃取头65μm PDMS/DVB的优化微萃取条件为:长度4 cm、70℃萃取50 min,从脯氨酸美拉德反应物中鉴定出64种挥发性成分,相对百分含量为83.39%,包括酯类14种(7.20%),酸类11种(6.28%),杂环化合物8种(8.91%),醇类8种(2.55%),酮类5种(6.68%),醛类5种(28.83%),胺类4种(4.29%),烷烃4种(0.9%),烯类3种(0.98%),酚类2种(16.77%)。     

采用3种萃取纤维头的顶空固相微萃取法萃取荜茇果穗挥发性成分

采用顶空固相微萃取法萃取荜茇果穗挥发性成分,并用GC-MS进行分析.3种萃取纤维头共萃取出49个成分,鉴定出42个成分.使用DVB/CAR/PDMS萃取纤维头时共检测出36种成分,解析鉴定出占总成分99.834%的35种成分,主要成分为β-石竹烯(17.933%)、β-毕澄茄油烯(15.892%)、十五烷(8.285%...     

SPME-GC/MS联合分析法测定食用菊花花朵挥发性成分研究

采用固相微萃取技术萃取食用菊花(Dendranthema morifolium)品种的挥发性成分,利用气相色谱-质谱联用技术(solid-phase microextractions-gas chromatgraphy mass spectrometrometry,SPME-GC/MS)进行分析,并用峰面积归一化法得出各组分的相对百分含量。结果显示:共鉴定出51种挥发性成分,包括烯类、酯类、醇类,还有少量酸、杂环类和烷类物质,其中主要成分为单萜类化合物α-蒎烯、β-月桂烯、α-松油烯、β-蒎烯、γ-松油烯等,相对含量分别为74.04%、5.24%、3.96%、3.44%、2.01%,共占总相对含量的88.69%。表明固相微萃取气相色谱-质谱联用技术方法能准确反映食用菊花中的挥发性组分,可为食用菊花资源的开发利用提供科学依据。     

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.     

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.     

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.     

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.