顶空固相微萃取-气质分析白芷香气成分研究

采用顶空固相微萃取和气相色谱-质谱研究白芷的香气成分。萃取纤维头为CAR/PDMS时共检测出35个成分,解析出占总挥发性成分的93.897%(相对百分含量,以下同)的33种物质,主要成分是1,8-桉树脑(16.713%),柠檬烯(15.495%),对伞花烃(7.620%)。萃取纤维头为DVB/CAR/PDMS时共检测出53种挥发性成分,解析出占总挥发性成分的91.360%的45种物质,主要成分是桉树脑(12.529%),依次为茴香脑10.836%,β-石竹烯8.922%。     

部分国内外卷烟主流烟气气相和粒相中挥发性、半挥发性成分的分析

分析了18种国内外品牌卷烟主流烟气中48种挥发性、半挥发性成分,研究了挥发性半挥发性化合物在气粒相的分配关系,结果表明:①气相中释放量较高的化合物分别是甲苯、柠檬烯、间二甲苯、乙苯和糠醛;粒相中释放量较高的化合物分别是丙二醇、乙酸、柠檬烯、2-呋喃甲醇和糠醛;②卷烟主流烟气中同一类挥发性、半挥发性成分的气相/粒相分配比随着其沸点的升高而减小;沸点相近的不同种类挥发性、半挥发性成分的气相/粒相分配比随着其极性的减小而升高;③卷烟主流烟气中挥发性、半挥发性成分的气相/粒相分配比与卷烟的类型没有明显的相关关系;④卷烟主流烟气中,大多数挥发性、半挥发性成分的气相/粒相分配比随着主流烟气焦油释放量的降低而增加,挥发性、半挥发性成分更容易向气相物转移。      

GC-O-MS结合感官评价鉴定白肋烟不良气息关键成分

为阐明白肋烟烟气不良气息关键成分,利用凝胶色谱和气相色谱-嗅闻-质谱联用（GC-O-MS）技术结合感官评价分别对白肋烟主流烟气粒相物和全烟气捕集产物进行分离及评价分析。结果表明：全烟气捕集产物较主流烟气粒相物的白肋烟不良特征气息明显,利用GC-O-MS技术从白肋烟全烟气捕集物中共鉴定出46种挥发性物质;通过气味活度值结合感官评价鉴定出9种白肋烟烟气关键特征成分,分别为三甲胺、吡啶、3-甲基吡啶、3-乙基吡啶、二甲基三硫、对甲酚、吲哚、3-甲基吲哚、2,3’-联吡啶。本研究明确了白肋烟烟气中不良气息关键成分,可为白肋烟原料质量评价及卷烟配方应用提供参考与指导。     

草果精油成分鉴定及其抗菌活性研究

Clevenger法萃取草果获得草果精油,采用GC-MS分析检测出38个成分,通过保留指数解析出占总成分9714%的30个成分,主要成分为1,8-桉树脑（4089%) , α-水芹烯（977%) , 4-丙基苯甲醛（699%）等. 与匹配度对照解析法比较,有24个成分一致,占总成分的9281%. 用外标法定量分析了主要成分1,8-桉树脑含量,其质量分数为480%. 然后,研究了草果精油和1,8-桉树脑的抗菌活性. 结果显示,精油具有明显的抗菌活性,而1,8-桉树脑几乎无抗菌活性. 精油对细菌的抗菌活性由大到小依次是枯草芽孢杆菌、白葡萄球菌、大肠杆菌;对霉菌的抑菌活性由大到小依次是米曲霉菌、根霉、青霉.     

香茅草产香菌发酵液的挥发性成分分析及在卷烟中的应用

采用同时蒸馏萃取和气相色谱/质谱法对香茅草[Cumbopogon citratus(DC.)Stapf]产香菌发酵液提取物的挥发性成分进行了分离鉴定,并进行了卷烟加香试验。结果表明:①该提取物中共鉴定出67种组分,其主要成分为柠檬烯、β-月桂烯、γ-萜品烯、金合欢烯、芳樟醇和γ-谷甾醇等;②该提取物具有增加烟香、略降低刺激性、明显改善烟气质的作用。     

老鹰茶游离和键合态挥发性成分的分析

以武陵地区老鹰茶作为研究对象,结合顶空固相微萃取(headspace solid-phase microextraction,HSSPME)与针捕集(needle trap,NT)对老鹰茶挥发性成分进行萃取,鉴定出老鹰茶中游离态和键合态47种挥发性化合物。其中包括32种游离态挥发性化合物和26种键合态挥发性化合物。结果表明,老鹰茶主要游离态挥发性化合物是乙酸龙脑酯、杜松醇、α-桉叶醇,键合态挥发性化合物是γ-桉叶醇、α-芹子烯、愈创木烯。测定的游离态和键合态芳香化合物中有17种香气活度值(odor activity value,OAV)大于1。从鉴定出的挥发性成分香气特征可知,老鹰茶游离态香气成分主要是正癸醛、十二醛、乙酸异龙脑酯、桉叶油醇、2-十一酮、正己醛,键合态香气成分是大马士酮、桉叶油醇、芳樟醇、2-己酮、D-柠檬烯、2-十一酮、正癸醛。     

甘油对烟丝加热状态下烟气中挥发性和半挥发性成分的影响

为考察甘油对烟丝加热状态下烟气粒相物中挥发性和半挥发性成分的影响,利用实验室加热装置,对不同甘油含量(质量分数)的烟丝(0～50%)在300℃下进行加热,捕集烟气粒相物,并采用气相色谱/质谱(GC/MS)法分析烟气中挥发性、半挥发性成分。结果表明:1烟丝中添加甘油可增加烟气中挥发性、半挥发性成分的释放量,但甘油添加量为5%～50%时,烟气中挥发性、半挥发性成分的总释放量无明显差异;2糠醛、6-甲基-3,5-二羟基-2,3-二氢吡喃-4-酮、5-羟甲基-2-糠醛等糖类裂解成分释放量相对较大,且随甘油添加量的增大呈先增加后降低趋势;3巨豆三烯酮、新植二烯等烟草固有成分的释放量随甘油添加量的增大呈逐渐增加趋势;4与空白样品相比,添加甘油的烟丝烟气中增加了甘油单羧酸酯,且随甘油添加量的增大呈持续增加趋势。烟丝中添加甘油有助于烟气粒相物中挥发性、半挥发性成分的释放,但对不同成分的影响趋势存在差异。     

两种方式加工鱼香肉丝的SDE-GC-MS挥发性风味成分对比

采用同时蒸馏萃取法结合气相色谱-质谱联用技术分别对鱼香肉丝市售菜肴和料理包中的挥发性风味成分进行提取与分离。结果共鉴定出136 种成分,市售菜肴鉴定出化合物79 种,料理包鉴定出化合物104 种,两种样品中均检测到的化合物有47 种,两者在酯类及含硫含氮及其他杂环化合物检出上存在较大差异。可能造成风味差异影响的化合物有：β-水芹烯、石竹烯、倍半水芹烯、苯甲酸甲酯、苯甲酸乙酯、桉树脑、2,3,5,6-四甲基吡嗪、二烯丙基三硫醚。     

顶空固相微萃取-气相色谱-质谱联用法分析仔姜与老姜的挥发性成分

以仔姜和老姜为原料,采用顶空固相微萃取-气相色谱-质谱联用法、以正癸烷为内标,分别对仔姜和老姜的挥发性成分进行分析。研究结果表明：从仔姜和老姜中共鉴定出89 种挥发性成分,其中仔姜中鉴定出63 种挥发性成分,主要包括37 种烃类、15 种醇类、6 种酯类、3 种醛类、2 种酮类,其主要挥发性成分为姜烯、橙花醇乙酸酯、β-雪松烯、α-法尼烯、（E）-柠檬醛、β-红没药烯;老姜中鉴定出68 种挥发性成分,主要包括45 种烃类、14 种醇类、3 种酯类、3 种醛类、3 种酮类,其主要挥发性成分为姜烯、α-姜黄烯、β-雪松烯、α-法尼烯、（E）-柠檬醛、β-红没药烯。     

新鲜薏仁米与异味薏仁米挥发性成分对比分析

以新鲜薏仁米和异味薏仁米为原料,采用顶空—固相微萃取—气质联用法分别对新鲜薏仁米和异味薏仁米的挥发性成分进行分析。研究结果表明:从新鲜薏仁米和异味薏仁米中共鉴定出85种挥发性成分,其中新鲜薏仁米中鉴定出47种化合物(主要包括12种醇类、11种醛酮类、22种烃类),其主要挥发性成分为右旋萜二烯、苯、2-戊基呋喃、己醛、壬醛、正辛醛、2-庚酮、正戊醇、正己醇、1-辛烯-3-醇和芳樟醇;异味薏仁米中鉴定出58种化合物(主要包括17种烃类、8种醇类、14种醛酮类、10种酯类和5种酸类),其主要挥发性成分为1-十五烯、己醛、壬醛、癸醛、正辛醛、正辛醇、己酸、庚酸、辛酸和壬酸。造成新鲜薏仁米与异味薏仁米的主要挥发性成分中酸类化合物种类和含量差异的主要原因,可能是新鲜薏仁米在贮藏过程中油脂的氧化。     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

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.     

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.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

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.