顶空进样器在快速检测食品美拉德反应风味物质中的新应用

本文利用顶空/气相色谱-质谱分析了70℃,90℃,140℃三个顶空保温条件下,大豆分离蛋白粉风味成分的变化.发现在140℃下,可检测到蛋白粉发生了明显的美拉德反应,其风味成分具有美拉德反应产物的特征,提示顶空/气相色谱-质谱联用可用于快速检测热加工食品美拉德反应所产生的风味物质.同感官评价法、同时蒸馏提取及气相色谱-质谱法和其他顶空-气相色谱-质谱法、顶空固相微萃取及气相色谱-质谱联用法相比较,顶空进样器同时作为美拉德反应的反应器以及反应风殊物质的萃取装置,方法具有快速、风味物质损失小的优点,适用于美拉德反应机理和应用研究.     

顶空固相微萃取-气相色谱-质谱法分析馥郁香型白酒风味物质

目的建立馥郁香型白酒风味物质的顶空固相微萃取-气相色谱-质谱分析方法。方法采用顶空固相微萃取法(head space-solid phase microextraction,HS-SPME)和气相色谱-质谱联用法(gas chromatographymass spectrometry,GC-MS)萃取及分析馥郁香型白酒中的风味成分,考察了稀释倍数、加盐处理与否、萃取时间、处理温度和萃取头类型对风味物质分析的影响。结果馥郁香型白酒风味物质的顶空固相微萃取-气相色谱质谱法最佳条件为:50μm/30μm DVB/CAR/PDMS Stableflex(grey)固相微萃取头,预处理时间120 s,处理温度60℃,预振荡速度300 r/min,萃取时间2400 s,解析时间300 s,解析温度300℃,稀释倍数为5:1,氯化钠加入量约2 g。结论建立的方法快速、简单,可用于白酒风味物质的检测。     

顶空固相微萃取气质联用技术在谷物食品中的应用研究进展

顶空固相微萃取结合气相色谱质谱联用技术可对谷物食品挥发性或难挥发性风味物质进行富集并对混合成分鉴定、定性定量分析,具有操作简便、高效、准确、无需有机溶剂等优点,是目前应用较为广泛的风味分析方法。该文概述顶空固相微萃取及气相色谱质谱技术的原理和特点,着重研究在谷物原料,不同种类谷物加工食品加工工艺、贮藏挥发性风味物质等的研究进展,同时对顶空固相微萃取气质联用技术在谷物食品研究方向进行展望。     

顶空固相微萃取-气相色谱法测定葡萄酒的风味组分

顶空固相微萃取技术是一种快速而简单的进样方法。顶空固相微萃取结合毛细管气相色谱技术无需复杂的样品制备过程就能有效测定葡萄酒中的风味化合物。本试验用标样定性了30个葡萄酒风味组分，并对与葡萄酒质量相关的风味化合物和影响定量结果的因素分别进行了讨论，大多数组分定量的相对标准偏差小于10％。     

牛肉和马肉Pastirma的挥发性风味物质分析

采用顶空固相微萃取技术对牛肉和马肉Pastirma中的风味物质组分进行萃取富集,然后采用气相色谱-质谱联用法对其化学组分进行分离及定性,共检测出49种化合物,其中包括:醛类、醇类、酮类、碳氢化合物类、醚类、有机硫化物、酯类,杂环类化合物和萜烯类化合物。并对两种Pastirma中的主要风味物质组分的差异进行了分析比较。     

食品挥发性风味分析技术概论

风味是食品重要的组成部分,影响着新产品的开发和消费者选择。食品挥发性风味复杂,种类多样,富含多种香气化合物。近年来很多研究者尝试运用风味化学的研究手段解析食品的风味成分特征,从而表征风味轮廓。本文从风味的定义,风味物质提取包括吹扫捕集、固相动态萃取（Solid Phase Dynamic Extraction,SPDE）、搅拌棒吸附萃取（Stir Bar Sorptive Extraction,SBSE）,风味成分的分析包括顶空分析（静态顶空、动态顶空）、气相色谱-嗅闻质谱（Gas Chromatography-Olfactometry-Mass Spectrometer,GC-O-MS）及可切换式全二维气相色谱-嗅闻-质谱（SGC×GC-O-MS）,分子感官科学包括关键气味活性化合物准确的定性定量分析、香气模型的构建、缺失实验和香气重组物等方面进行总结,以期为食品风味研究技术的提升和风味品质的改善提供新的思路和技术参考。     

植物油中挥发性风味成分分析鉴定技术研究进展

植物油富含多种功能成分,广泛应用于食品、饲料、化工等行业。挥发性风味成分与植物油的品质息息相关,而分析鉴定技术是植物油风味成分研究的基本手段。本文对国内外植物油中挥发性风味成分的分析前处理技术（同时蒸馏萃取法、水蒸气蒸馏法、顶空法、固相微萃取技术、溶剂辅助蒸发法等）和鉴定方法（气相色谱法、气相色谱-质谱联用法、气相色谱-嗅闻法、香气活性值法、电子鼻技术、全二维气相色谱飞行时间质谱法）的原理、特点、应用状况进行了概述,并对各种方法进行了比较,旨在为风味食用植物油的开发提供一定的数据参考。     

不同饲养方式的部位肉制作的哈萨克风干牛肉挥发性风味成分差异分析

采用电子鼻和固相微萃取-气相色谱-质谱联用法分析了2种不同饲养方式、3个不同肌肉部位样品的挥发性风味成分。电子鼻分析结果表明,2种不同饲养方式的样品之间风味差异较大,相同饲养方式、不同肌肉部位的样品之间风味差异较小。固相微萃取-气相色谱-质谱法共检测出26种挥发性风味物质,包括醛类8种、醇类7种、含苯芳香化合物6种、脂肪烃3种、酮类1种、呋喃1种。方差分析结果表明,肌肉类型对来自脂肪氧化产物总量有显著影响(P0.05),而饲养方式对来自饲料成分总量有极显著影响(P0.01)。     

电子鼻结合气相色谱-质谱联用技术分析贮存条件对马铃薯面包挥发性成分的影响

以常温、冷藏的马铃薯面包为研究对象,采用电子鼻结合顶空固相微萃取-气相色谱-质谱联用技术,分析常温第1天、第6天和冷藏第6天的马铃薯面包样品挥发性成分。结果表明,电子鼻分析结果能够很好地区分常温和冷藏1～9?d马铃薯面包的风味。采用主成分分析和线性判别分析可以量化主成分贡献率和样品间风味的区分度,并利用判别因子分析建立马铃薯面包识别库模型。顶空固相微萃取-气相色谱-质谱联用分析结果表明,3?种马铃薯面包共检测出28?种挥发性风味物质,其中常温第1天17?种,冷藏第6天4?种,常温第6天14?种;经贮藏后,风味物质变化明显,冷藏样品酸类、酯类、酮类和烃类物质消失,常温样品贮藏后醛类和醚类消失,醇类化合物相对含量都显著增加。因此,电子鼻结合气相色谱-质谱联用技术可对贮藏期马铃薯面包的风味进行综合评价。     

GC-MS法检测川菜中挥发性成分的研究

建立并优化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。样品萃取选择65μm聚二甲基硅氧烷/二乙烯苯固相微萃取头,50℃顶空萃取40 min。通过气相色谱-质谱法对4种不同味型川菜中的挥发性成分进行分析,共检出酯类、酸类、酚类、醚类、酮类、醇类、烃类等7类36种化合物。该方法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基础数据。     

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.     

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.     

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.     

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.     

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.     

Analysis on Economic Indicators from 62 Enterprises in Printing Machinery Industry in Q1 2014

Operation of printing machine industry was still unsatisfactory in the first quarter of 2014.Analysis on operation of printing machine industry.a.Market demand was not strong;sales of product undulated and declined.According to the statistics,the total industrial output value fell by 19.28% in the first quarter of 2014 than the average quarter value in 2013; industrial added value decreased by 4.16%; sales revenue dropped by 22.83%. h. Business operation of enterprises was in poor condition. c. R＆D of new products is an important transformation guarantee for enterprises. d. To take self explore new ways upgrading advantages,and explore new ways.