响应面法优化籼稻挥发性成分SPME萃取条件的研究

应用顶空固相微萃取(SPME)技术结合气相-质谱法(GC-MS)对籼稻挥发性成分进行分析,并优化SPME的萃取条件。首先考察萃取量、萃取温度、平衡时间、萃取时间、解析时间对籼稻挥发性成分萃取的影响,在单因素试验的基础上进行响应面分析优化SPME萃取条件,以优化的最佳条件结合GC-MS对籼稻挥发性成分进行分析。结果表明:籼稻挥发性成分的最佳SPME萃取条件为萃取温度75℃、平衡时间59min、萃取时间60 min、解析时间5 min。籼稻含有烃类、醛类、含氮含氯含氧及杂环类、酸酯类、酮类、醇类等84种挥发性成分。     

不同萃取头固相微萃取分析小米清酒挥发性成分的研究

采用PA、PDMS、PDMS/DVB、CAR/PDMS和DVB/CAR/PDMS 5种萃取头,并通过固相微萃取（SPME）与气质联用（GC-MS）对小米清酒中挥发性成分进行提取、鉴定,运用聚类热图分析不同SPME萃取头提取小米清酒挥发性成分差异。结果表明：5种萃取头SPME检测到小米清酒挥发性成分含有醇、酯、醛、碳氢化合物、含苯衍生物和其他化合物,使用不同萃取头进行固相微萃取能得到较为相似的主挥发性成分：1-戊醇、苯乙醇、正己酸乙酯、丁二酸二乙酯、辛酸乙酯、十六烷,DVB/CAR/PDMS萃取头检测效果最好。聚类热图显示,不同萃取头SPME提取到的挥发性成分效果差异较大,按萃取效果可分为PA萃取头、PDMS萃取头和复合萃取头（PDMS/DVB、CAR/PDMS和DVB/CAR/PDMS）三类,使用不同种萃取头SPME可较为全面地了解小米清酒挥发性成分构成。     

SPME-GC-MS 法测定冷却肉的挥发性成分

对固相微萃取(SPME)萃取条件进行优化,并利用SPME 对冷却肉的挥发性成分进行提取。应用SPME 结合气相色谱- 质谱(GC-MS)联用技术初步鉴定冷却肉的挥发性成分,并分析其在不同贮藏温度以及不同贮藏时间下挥发性成分的气味变化。结果表明：在35℃萃取温度和40min 萃取时间的条件下,宜采用65μm PDMS/DVB 萃取头对冷却肉的挥发性成分进行萃取;经SPME-GC-MS 检测后,共获得25 种挥发性成分,并发现醇类物质和三甲胺的相对含量会随着贮藏时间的变化而不断增加。     

SPME/SDE-GC-MS分析宁德养殖大黄鱼挥发性化合物

大黄鱼(Larimichthys crocea)是我国养殖规模最大的海水鱼,福建宁德是我国大黄鱼最主要的养殖基地。该文揭示养殖大黄鱼的主要挥发性成分。分别采用固相微萃取(solid-phase microextraction,SPME)和同时蒸馏萃取(simultaneous distillation extraction,SDE)萃取福建宁德养殖大黄鱼的挥发性成分,结合气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)和相对气味活度值(relative odor activity value,ROAV)对其挥发性化合物进行分析。结果表明:共检测到49种挥发性化合物,但SPME和SDE两种方法提取的大黄鱼挥发性化合物成分差异明显;其中SPME提取的挥发性化合物以醛类、醇类、烃类和芳香烃化合物为主,SDE提取的挥发性化合物以酮类和酯类化合物为主。通过ROAV分析确定9种关键香气成分,包括辛醛、壬醛、反-2-辛烯醛、反,反-2,4-癸二烯醛、1-辛烯-3-醇、反,正-2,6-壬二烯醛、反-2-癸烯醛、癸醛和柠檬烯。SPME和SDE两种提取方法结合GC-MS分析较全面揭示了福建宁德养殖大黄鱼的主要挥发性成分。     

红烧猪肉工艺优化及其挥发性风味成分的分离与鉴定

基于模糊数学感官评价法优化红烧猪肉制作工艺参数(焯水时间、焖焅温度、焖焅时间)。采用固相微萃取(SPME)预处理与气相色谱-质谱(GC-MS)联用技术相结合对红烧猪肉中挥发性风味成分进行分离鉴定。结果表明,红烧猪肉的最佳工艺条件为:焯水时间3 min,焖焅温度100℃,焖焅时间2.5 h。对SPME萃取参数(平衡时间、萃取温度、萃取时间)进行优化,确定较佳的萃取条件是:水浴温度60℃下平衡10 min,萃取35 min。通过SPME-GC/MS共鉴定出60种挥发性风味成分,包括醇类10种、醛类10种、脂肪烃类15种、酯类5种、酮类7种、含S、N化合物7种及其它化合物6种。红烧猪肉挥发性风味成分中醛类比例最高(24.68%),其次含S、N化合物(20.99%)、脂肪烃类(19.57%)、醇类(16.88%),而酯类、酮类及其它化合物比例较低(10%),其中己醛(0.72μg/g)、柠檬烯(0.51μg/g)、硫化丙烯(0.51μg/g)为含量较高的化合物。     

同时蒸馏与固相微萃取法对酱油香气成分提取的比较研究

采用同时蒸馏萃取（SDE）和固相微萃取（SPME）对酱油中挥发性香气成分进行提取,结合气-质联用（GC-MS）仪进行检测,并采用峰面积归一化法分析各成分的相对含量。结果显示,SDE法检测出73种挥发性物质,SPME法检测出61种挥发性物质,两种方法共检测出114种物质。SDE法有利于萃取出酱油中重要的挥发性风味物质碳氢类及呋喃类（18.16%）,SPME法未检出碳氢类且对呋喃类（2.55%）的吸附相对较少,但萃取出的其他类化合物（18.98%）相对较多,而SDE法检测出的其他化合物（5.38%）较少。     

南疆多浪羊不同部位脂肪组织中挥发性风味成分分析

采用顶空固相微萃取(solid-phase microextraction,SPME)技术结合气相色谱-质谱法(gas chromatography-mass spectrometry,GC-MS),对新疆多浪羊不同部位脂肪组织中挥发性风味物质的组成进行研究,共检测出78种化合物,其中以酸类、酯类和醛类为主。尾部脂肪组织中酸类化合物占37.50%,皮下脂肪组织中酸类化合物占41.38%,肠道脂肪组织中酯类化合物占43.48%,肾脏周围脂肪组织中酸类化合物占29.63%。不同部位脂肪组织中挥发性风味化合物的组成不同,酸类化合物为主要成分,推测短链挥发性脂肪酸是多浪羊肉特征风味的主要组成成分。     

不同烹饪方式川菜中挥发性成分的研究

实验建立并优化了一种顶空固相微萃取-气质联用法检测川菜中挥发性成分的研究方法。样品的萃取选择65μm PDMS/DVB(聚二甲基硅氧烷/二乙烯苯)SPME萃取头,50℃顶空萃取40min。通过GC-MS对4种不同烹饪方式川菜中的挥发性成分进行了分析,共检出酯类、酸类、酚类、醚类、酮类、醇类、烃类7类36种化合物。该方法具有萃取方法简单、灵敏度高的优点,适用于川菜中多种挥发性成分的分析,为研究川菜菜肴提供了基础数据。     

HS-SPME结合GC-MS分析麻婆豆腐中挥发性风味成分

测定麻婆豆腐中挥发性风味成分,对中式菜肴风味稳定及工业化生产有重要贡献。采用顶空固相微萃取(HS-SPME),结合气质联用技术(GC-MS)分析了实验室自制麻婆豆腐中挥发性风味成分,并对萃取头、预热时间、萃取时间、萃取温度进行了优化。确定了较佳的萃取条件:采用65μm PDMS/DVB的纤维萃取头,60℃预热30 min,萃取30 min。通过GC-MS检测,在麻婆豆腐中一共检测出挥发性风味物质共74种,主要包括烷烯烃类、醇类、醛类、脂类等化合物。含量较多的物质有:萜品油烯、左旋-beta-蒎烯、月桂烯、3-蒈烯、b-侧柏烯、(-)-柠檬烯等。研究表明,顶空固相微萃取技术及气质联用技术能很好的用来分析麻婆豆腐中的挥发性风味物质,且样品萃取条件的不同对麻婆豆腐风味成分的准确测定具有一定影响;不同种类的麻婆豆腐的在感官评鉴上也有所差异。     

顶空固相微萃取-气质联用技术检测油菜籽中挥发性成分

目的采用气相色谱-质谱(GC-MS)技术对正常油菜籽与霉变油菜籽中挥发性成分进行鉴定和分类分析。方法采用顶空固相微萃取(HS-SPME)技术对油菜籽中的挥发性成分进行萃取,优化顶空固相微萃取的微萃取头、萃取温度、萃取时间和解析时间等条件,并结合气相色谱-质谱(GC-MS)技术对正常油菜籽与霉变油菜籽中挥发性成分进行测定。结果顶空固相微萃取的最佳条件为固相萃取头30/50μmDVB/CAR/PDMS、萃取温度60℃、萃取时间60 min、解吸时间3 min。在最佳实验条件下,GC-MS鉴定出油菜籽中挥发性成分主要有醛类、酮类、醇类、烃类、少量酸、酯类物质及杂环类等多种组分,其中烃类含量最高;3-辛酮、苯乙酮、苯乙醛、苯乙醇、以及十九烷、二十一烷等烷烃类化合物仅在霉变油菜籽中检出。结论该方法可较好地区分正常油菜籽与霉变油菜籽。     

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.