HS-SPME-GC-MS联用分析不同产地肉桂挥发性成分

目的:分析比较不同产地肉桂挥发性成分的组成。方法:采用顶空固相微萃取-气相色谱-质谱(HS-SPME-GC-MS)联用技术,对不同产地的肉桂中挥发性化学成分进行定性分析,以峰面积归一化法计算各组分的相对含量,并通过主成分分析和聚类分析对数据进行处理。结果:4个产地肉桂的总离子流图整体上相似,12个批次的样本在聚类和主成分空间中聚集成为不同的类别,基本实现不同产地肉桂的鉴别,此外,在一定程度上,样本分布疏密度反映样本的亲缘关系。结论:本实验方法稳定可靠,适用于肉桂挥发性成分的快速分析,可鉴别不同产地肉桂,并且能反映不同产地肉桂挥发性成分含量的差异,为肉桂的质量评价提供一定的科学依据。     

肉桂添加量对卤鸡腿肉挥发性风味成分的影响

比较不同肉桂添加量对卤鸡腿肉挥发性风味成分的影响。设置5个梯度的肉桂添加量(0%,0.05%,0.1%,0.2%,0.3%),采用电子鼻(EN)、顶空固相微萃取(HS-SPME)和气质联用(GC-MS)的方法对不同肉桂添加量的卤鸡肉样品进行检测分析。结果显示:不同肉桂添加量鸡肉样品的电子鼻信号表现出较强的聚类特性;按肉桂添加量由低到高的顺序经GC-MS依次检出54、60、63、65、80种挥发性风味物质;与空白组相比,添加肉桂的鸡肉样品中新增了肉桂醛、桉叶油醇、香叶基丙酮、香豆素、对异丙基甲苯、石竹烯等40种挥发性风味物质,以0.3%肉桂组增加的萜烯类物质最多。表明添加肉桂后鸡肉样品中新增的挥发性风味物质多属于肉桂添加的直接引入。肉桂添加浓度达到0.3%时,样品中萜烯类物质急剧增加,风味成分变化较大。     

AMDIS-SPME-GC/MS分析不同产地鱼露中的挥发性物质

目的:鉴定不同产地鱼露的挥发性物质。方法:采用顶空固相微萃取与气相色谱-质谱联用结合,对不同产地鱼露中的挥发性物质进行分析检测,结合相对保留指数、质谱自动解卷积系统对挥发性物质进行定性。结果:5种鱼露样品共有93种挥发性物质,其中广东鱼露样品中酯类和芳香类挥发性物质的相对含量高,泰国鱼露样品中酮类挥发性物质的相对含量高,越南鱼露样品中酸类和杂环类挥发性物质的相对含量高,实验室自制鱼露样品中烃类、醛类和醇类挥发性物质相对含量高。五种鱼露不同个批号的样品经验证积分器(Assignment Validator and Integrator,GAVIN)自动峰对齐后,检出各自的独有组分35种,共有组分11种。共有组分被用于主成成分分析,不同产地的鱼露在主成分分析图上得到较好的分离。结论:提供了不同产地鱼露气味物质的特征,提供了一种利用气质联用的挥发物分析进行产品产地溯源的方法和工作流程。     

不同产地抹茶的香气成分分析

为了解不同产地的抹茶香气成分,以日本静冈、浙江金华、贵州铜仁3个产地的抹茶为原料,采用热脱附法提取样品的香气成分,并通过气相色谱-质谱及氢火焰离子检测器法(GC-MSD-FID)进行分析,深入研究抹茶的香气成分特征及不同产地的香气差异。其中日本静冈抹茶样品分析出来65种挥发性成分,浙江金华抹茶样品54种,贵州铜仁抹茶样品70种,不同产地抹茶分析出来的挥发性物质组成和相对含量间的差异、以及独有的香气物质体现出不同产地风味的区别。     

不同产地压榨山茶油挥发性风味成分顶空取样GC-MS分析

采用顶空取样结合GC-MS技术比较分析不同产地压榨山茶油的挥发性风味成分。结果表明:在样品用量4 g、顶空平衡温度150℃、顶空平衡时间25 min、进样时间1 min条件下,分析效果最理想;从不同产地压榨山茶油样品中共鉴定出117种挥发性风味成分,共有成分20种,主要为醛类化合物,不同产地间挥发性风味成分含量有差异,且海南山茶油主要挥发性风味成分含量与内地(湖南、江西、广西)山茶油区别较大。     

不同品种及产地鲜天麻挥发性物质差异性分析

目的：分析不同品种和不同产地鲜天麻中挥发性化合物的差异。方法：采用气相—离子迁移色谱(GC-IMS)技术对6个产地、3个品种的鲜天麻挥发性物质成分进行测定，利用VOCal和Reporter、Gallery Plot和Dynamic PCA三款插件及“最近邻”指纹分析，分别从不同角度对样品进行定量定性分析。结果：研究共检出75种挥发性化合物，其中可以鉴定出的物质45种，包括16种醛类、9种酯类、6种醇类、5种酮类和3种酸类物质。采用主成分分析能够有效区分不同品种鲜天麻样品，但对不同产地鲜天麻区分有效性差。结论：GC-IMS可以实现对不同品种鲜天麻样品挥发性化合物的差异进行快速分析。     

不同产地初榨菜籽油挥发性风味成分比较分析

为了研究不同产地初榨菜籽油挥发性成分的变化规律,采用气相色谱-质谱和电子鼻相结合的方法,对不同挥发性风味成分进行比较研究。利用气相色谱-质谱数据对关键风味成分的相对气味活度值（ROAV）进行主成分分析,确定其主体挥发性成分。应用综合评价指标（GEI）对各产地初榨菜籽油香气进行评价。结果表明:由10个产地样品共检测出177种挥发性成分,根据ROAV鉴定出14种主体风味成分,主要包括硫甙降解产物、醛类和吡嗪类等。各产地的挥发性成分主要是3-乙基-2, 5-甲基吡嗪、壬醛、2, 4-癸二烯醛、甲烯丙基氰、苯乙醛、月桂醛等,不同产地菜籽油样品香气差别显著,GEI评价结果表明,香气品质最优的产地是成都。各产地初榨菜籽油挥发性成分既有一定的相似性,但差异性也较大,展现其各自独特的风味。     

基于气相离子迁移谱黄酒产地识别的研究

为建立一种快速、准确的黄酒产地鉴别方法,本研究运用气相-离子迁移谱(Gas Chromatography-Ion Mobility Spectrometry,GC-IMS)对不同产地的黄酒中的挥发性有机成分进行分析,构建黄酒产地信息的气味指纹图谱,并对不同产地的黄酒样品进行了判别和分类。采用二维差谱方法筛选16个有效特征峰作为表征黄酒产地差异信息的特征变量,采用主成分分析(Principal Component Analysis,PCA)和线性判别分析(Linear Discriminate Analysis,LDA)方法建立判别模型。结果表明,选取的特征变量经PCA处理后前两个主成分的累积贡献率为96.07%,不同产地的黄酒样品在主成分分析图中均有对应的归属区域,以前2个主成分得分结合LDA方法可以有效的区分不同产地的黄酒样品,预测集中识别率高达94.44%。研究表明,GC-IMS技术结合化学计量学方法能够快速、准确、直观地区分不同产地的黄酒样品,为黄酒的鉴别和原产地保护提供了一种新的检测方法。     

顶空固相微萃取-气相色谱-质谱联用法分析丁香与肉桂子的香气成分

目的采用顶空固相微萃取结合气相色谱-质谱联用技术(headspacesolid-phasemicroextraction-gas chromatography-massspectrometry,HS-SPME-GC-MS)对天然调味品丁香和肉桂子挥发性成分进行研究,揭示丁香与肉桂子主要香气成分并比较二者差异。方法样品经85℃加热30 min,顶空富集10 min,在250℃解析5min,再利用GC-MS进行测定,对丁香与肉桂子产生独特香气的化学成分进行分析,并用面积归一化法计算各成分的相对百分含量。结果 2种药材共检测到120个峰,共鉴定出56种主要成分。从丁香中检测到60个峰,鉴定出20种成分,占总挥发性成分的98.71%,其主要成分为β-石竹烯、丁香酚、α-律草烯、乙酸丁香酚酯等;从肉桂子中检测到60个峰,鉴定出45种成分,占总挥发性成分的97.31%,其主要成分为肉桂醛、(+)-d-杜松烯、δ-衣兰油烯、(-)-α-蒎烯、(-)香树烯等。结论虽然丁香和肉桂子的性状、气味相似,但所含挥发性成分有所差异,具有9种共同香气成分,其中β-石竹烯为主要香气成分。丁香中的α-律草烯和(-)-氧化石竹烯的含量更丰富,另外6种成分均低于肉桂子。研究结果为分析与鉴别丁香和肉桂子的挥发性香气成分提供科学依据。     

HS-SPME-GC-MS法分析肉桂子挥发性化学成分

采用顶空固相微萃取(HS-SPME)及水蒸气蒸馏(SD)方法对内桂子中挥发性成分进行提取.进而采用气相色谱质谱联用(GC-MS)对提取物分析鉴定.两种提取方法相互补充,共鉴定出59种挥发性成分.不同提取方法所得肉桂子主要挥发性化学成分相近,含量稍有不同,包括肉桂醛、γ-衣兰油烯、α-古巴烯、石竹烯和邻甲氧基肉桂醛等.研究结果表明,将肉桂子开发成为药食两用调味品具有很好的前景.     

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.     

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.     

低温带皮菜籽粕微粉的不同粒级部分的功能特性

为研究低温带皮菜籽粕微粉的不同粒级部分的功能特性,以经低温脱脂的带皮菜籽粕为原料,经微粉碎后筛分成212~425μm、150~212μm和106~150μm的3个不同粒级的微粉样品,检测这些样品的吸水性、吸油性、乳化性和乳化稳定性、蛋白质体外消化率。结果表明:1 3个不同粒级的微粉样品之间的粗纤维含量存在显著差异,表明三者的结构组成成分有一定差异。23个微粉样品的乳化活性和乳化稳定性随粒度级别的减小而显著增加(P0.01)。33个微粉样品的蛋白质体外消化率随粒度级别的减小而显著增加(P0.01)。4不同粒级带皮菜籽粕微粉样品的吸水性与吸油性受其结构组成物质不同和粒度的双重影响,与粒度的相关性不明显。     

Microbiology of food taints

Fresh and processed foods are often spoilt by the presence of undesirable flavours and odours caused by microbial action. The aim of this paper is to review the current knowledge of microbiologically induced taints that occur in a wide range of foodstuffs, including meats, poultry, fish, crustaceans, milk, dairy products, fruits, vegetables, cereals and cereal products. Examples have been chosen where the compounds responsible for the taint have been identified and sufficient data obtained to demonstrate the involvement of microorganisms. However, in some cases the full identity of the causative organism may not have been elucidated. The types of microorganisms covered by this review include bacteria, fungi, yeasts, actinomycetes and cyanobacteria. Although cyanobacteria do not in general infect foods, their presence in aqueous systems and water supplies can lead to off-flavours in aquatic organisms and processed foodstuffs. Several examples of each of these processes are discussed. Wherever possible, the likely biosynthetic pathway used by the microorganism to produce the offending compound in a foodstuff is indicated.     

Analysis for organic residues from aids to polymerization used to make plastics intended for food contact

Polymers intended for food contact use have been analysed for organic residues which could be attributed to a range of substances employed as polymerization aids (e.g. initiators and catalysts). A wide range of polymers was extracted with solvents and the extracts analysed by gas chromatography-mass spectrometry (GC-MS). The overwhelming majority of substances identified were not derived from aids to polymerization but were oligomers, additives and adventitious contaminants. However, a small number of substances were identified as initiator residues. These included tetramethylsuccinonitrile (TMSN) which was observed in two polymers and it derived from recombination of two azobisisobutyronitrile (AIBN) initiator radicals. Methyl benzoate, benzoic acid, biphenyl and phenyl benzoate were detected in one poly(methyl methacrylate) sample and in two polyvinylchlorides and they are thought to be derived from benzoyl peroxide initiator. TMSN was subsequently targeted for analysis of poly-(methyl methacrylate) plastics using proton nuclear magnetic resonance spectrometry (¹     

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

Experiments were performed to characterize the kinetics of the permeation of different medium molecular weight model permeants: bisphenol A, warfarin and anthracene, from liquid paraffin, through a surrogate potential functional barrier (25 microns-thick orientated polypropylene--OPP) into the food simulants olive oil and 3% (w/v) acetic acid. The characterization of permeation kinetics generally observed the permeation models previously reported to explain the experimental permeation results obtained for a low molecular weight group of model permeants. In general, the model permeants exhibited behaviour consistent with their relative molecular weights with respect to (a) the time taken to attain steady-state permeation into the food simulant in which they were more soluble, (b) their subsequent steady-state permeation rates, and (c) their partition between liquid paraffin and the OPP membrane.     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. I: Interlaboratory studies of methods of analysis

This paper describes the first part of a project undertaken to develop mussel reference materials for Paralytic Shellfish Poisoning (PSP) toxins. Two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin (STX) and decarbamoyl-saxitoxin (dc-STX) in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the second part of the project: the certification exercise. In the first study, 18 laboratories were asked to measure STX and dc-STX in rehydrated lyophilized mussel material and to identify as many other PSP toxins as possible with a method of their choice. In the second interlaboratory study, 15 laboratories were additionally asked to determine quantitatively STX and dc-STX in rehydrated lyophilized mussel and in a saxitoxin-enriched mussel material. The first study revealed that three out of four postcolumn derivatization methods and one pre-column derivatization method sufficed in principle to determine STX and dc-STX. Most participants (13 of 18) obtained acceptable calibration curves and recoveries. Saxitoxin was hardly detected in the rehydrated lyophilized mussels and results obtained for dc-STX yielded a CV of 58% at a mass fraction of 1.86 mg/kg. Most participants (14 out of 18) identified gonyautoxin-5 (GTX-5) in a hydrolysed extract provided. The first study led to provisional criteria for linearity, recovery and separation. The second study revealed that 6 out of 15 laboratories were able to meet these criteria. Results obtained for dc-STX yielded a CV of 19% at a mass fraction of 3.49mg/kg. Results obtained for STX in the saxitoxin-enriched material yielded a CV of 19% at a mass fraction of 0.34mg/kg. Saxitoxin could not be detected in the PSP-positive material. Hydrolysis was useful to confirm the identity of GTX5 and provided indicative information about C1 and C2 toxins in the PSP-positive material. The methods used in the second interlaboratory study showed sufficiently consistent analysis results to undertake a certification exercise to assign certified values for STX and dc-STX in lyophilized mussel.     

Focus on China's Paper Industry

In the English section of this issue, 〈China Paper Newsletters〉 will introduce ＂National Development and Reform Commission Issued Announcement for Selection of Major Preliminary Research Projects for the ＇13th Five-Year Plan＇＂, ＂2013 Annual Report of China＇s Paper Industry＂, and news of projects and other policies.     

Listen to downstream & search for innovation

正Nowadays,textile enterprises are all taking efforts in transformation and upgrading,like improving producing capacity and optimizing production structure to face market downturn.It claimed a higher request to the standard of textile equipments.In the upcoming of ITMA ASIA+CITME 2014exhibition,this magazine have interviewed several branch associations and a series of relative enterprises,to summarize industrial developing status