蜂蜜酒发酵前后挥发性风味成分的迁移变化

目的 探究蜂蜜酒发酵前后挥发性风味成分的迁移变化。方法 本研究采用电子鼻（electronic nose,E-nose）和气相色谱-离子迁移谱联用（gas chromatography-ion mobility spectrometry,GC-IMS）技术对蜂蜜酒发酵前后挥发性风味成分的迁移变化进行比较分析。建立指纹图谱、气相离子迁移谱图,对挥发性物质进行定性分析,同时结合主成分分析（principal component analysis,PCA）比较样品间差异。结果 电子鼻检测发现发酵后甲基类物质和醇类、醛类、酮类物质明显增加;GC-IMS检测出53种挥发性物质,定性出26种挥发物质组分,发酵后2-甲基丁醛、己醛、2-甲基-1-丙醇、乙酸、乙醛、乙酸乙酯、正丙醇、丁酸乙酯、乙酸异戊酯、丁醇、3-甲基-1-丁醇、辛酸乙酯、丙烯醛和乙酸异丁酯等风味物质成分明显增加。结论 经过发酵后的蜂蜜酒在保留蜂蜜原有风味的同时又显著增加了大量新的风味成分,形成蜂蜜酒独特的风味特征。     

HS-SPME-GC-MS结合电子鼻对10 个品系红松籽油挥发性物质分析比较

采用顶空固相微萃取与气相色谱-质谱（headspace solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS）联用技术结合电子鼻（electronic nose,E-nose）对10 个品系（种）红松籽油挥发性物质进行区别和比较。10 个样品中GC-MS共鉴定163 种挥发性物质,包含烃类、醇类、醛类、酯类、酮类、酸类等类型的挥发性物质,且以烃类、醛类、醇类和酯类为主,主要贡献风味的物质为醛类、醇类和酯类。通过聚类分析和主成分分析（principal component analysis,PCA）对10 个红松籽油品系进行区分,可以将样品分为3 组,各组之间的挥发性成分含量存在显著差异。采用PCA和线性判别分析处理E-nose数据,PC的累计贡献率分别达到97.17%、88.82%,说明传感器识别度高、样品间区分度好。2 种技术相关性分析结果表明,信号传感器与不同挥发性物质存在相关性。本研究评价10 个品系松籽油的挥发性物质,探讨HS-SPME-GC-MS与E-nose相结合用于区别和比较10 个品系松仁油挥发性成分的可行性。     

基于气相色谱-离子迁移谱分析石花白酒风味特征

为研究石花典型白酒在挥发性风味成分种类及相对含量之间的特征差异,采用气相色谱-离子迁移谱（GC-IMS）技术对白酒中的挥发性风味成分进行分析,并绘制风味指纹图谱对白酒的香型和品种进行分析对比,通过主成分分析（PCA）对白酒进行分类鉴别。结果表明,石花白酒中共检出18种挥发性风味物质,其中酯类5种、醛类6种、酮类3种、醇类2种、酸类1种和呋喃类1种。通过指纹图谱对比特征风味成分,可以清楚区分不同香型、不同品种的白酒;通过主成分分析（PCA）,能够基于挥发性风味物质对石花白酒样品进行分类鉴别。     

不同品种鸡肉蒸煮挥发性风味成分比较研究

利用固相微萃取-气相色谱-质谱(SPME-GC-MS)联用内标法对不同品种鸡肉的蒸煮挥发性风味物质进行定性定量分析,基于挥发性物质种类及含量差异,对鸡肉蒸煮主要风味物质进行主成分分析,并对品种进行聚类分析。同时利用电子鼻(E-nose)风味分析技术,对鸡品种进行种类区分。结果表明:10种蒸煮鸡肉共鉴定出72种挥发性物质,其中醛类20种、酮类7种、醇类11种、其它化合物34种,共有的挥发性风味物质19种。不同品种鸡肉相比,柴母鸡和乌鸡的挥发性风味物质种类较多,分别为49和46种;清远鸡和北京油鸡的醛类含量较高,分别为11785.47和11050.57 ng/g。主成分分析表明,蒸煮鸡肉主要挥发性物质为(E)-2-壬烯醛、(E)-2-辛烯醛、庚醇和2-癸酮。基于蒸煮鸡肉中挥发性风味物质种类和含量不同,可将10个品种鸡肉聚为两类。采用电子鼻分析技术,可将中国地方品种鸡与白羽肉鸡很好地区分。     

基于气相色谱-离子迁移谱分析红糖和赤砂糖挥发性风味成分差异

目的 为探明红糖和赤砂糖挥发性风味物质差异, 建立一种红糖及赤砂糖快速鉴别的气相色谱-离子迁移谱(gas chromatography-ion mobility spectrometry, GC-IMS)检测方法。方法 以3种红糖和3种赤砂糖为研究对象, 采用GC-IMS测定样品中的挥发性化合物, 并进行主成分分析。结果 从红糖和赤砂糖中共鉴定出65种已知物质, 包括17种醛类、11种吡嗪类、7种醇类、9种酯类、6种酸类、10种酮类以及其他5种化合物, 其中甲基丙醛、2,6-二甲基吡嗪-D、2,5-二甲基吡嗪、2-甲基丙酸、2-甲基丁酸在红糖和赤砂糖中含量差异较大; 主成分分析结果表明, 红糖和赤砂糖挥发性成分存在明显差异, 说明GC-IMS技术能够将红糖和赤砂糖进行区分。结论 本研究通过GC-IMS技术建立了红糖和赤砂糖挥发性成分指纹图谱, 可视化呈现红糖和赤砂糖挥发性成分差异, 为红糖和赤砂糖鉴定分析提供了依据。     

电子鼻结合顶空SPME-GC-MS联用技术分析贵州不同品种辣椒发酵后挥发性成分

以贵州5种不同辣椒品种为研究对象,采用电子鼻技术,结合顶空固相微萃取-气相色谱-质谱（solid phase microextraction-gas chromatography-mass,SPME-GC-MS）联用技术,对其发酵后挥发性成分进行分析。结果表明,电子鼻分析结果能够很好地区分不同辣椒品种发酵后的风味;采用主成分分析（principal component analysis,PCA）以及线性判别分析（linear discriminant analysis,LDA）可知,PCA和LDA主成分贡献率总和分别为99.93%、99.19%,均大于95%,说明传感器识别效应和样品间的风味区分度较好。SPME-GC-MS分析结果表明,5种样品共检出124种不同的挥发性风味物质。其中黄平线椒占97种,以酯类物质相对含量最高,为36.82%;施秉线椒和大方皱椒分别占88种和94种,且均以醇类物质相对含量最高,分别为31.88%、28.99%;百宜平面椒和花溪党武辣椒分别占89种和71种,均以烃类物质相对含量最高,分别为26.75%、35.08%。此结果与电子鼻PCA和LDA结果相一致。因此,通过SPME-GC-MS和电子鼻分析结果可知,电子鼻能够很好地区分贵州名优产地不同辣椒品种发酵后的风味。     

GC-IMS法比较不同酒龄猕猴桃酒特征香气物质差异

比较不同酒龄猕猴桃酒挥发性特征香气物质的差异，为建立不同酒龄猕猴桃酒的鉴别方法和进一步建立不同酒龄猕猴桃酒整体品质评价的新方法提供思路。对不同酒龄猕猴桃酒的挥发性物质，采用气相色谱-离子迁移谱（gas chromatography-ion mobility spectrometry，GC-IMS）进行检测并比较成分变化，结合主成分分析（PCA）和“最近邻”指纹分析分析其挥发性物质的差异。GC-IMS指纹图谱显示，不同酒龄猕猴桃酒的挥发性物质存在差异，明确定性的挥发性物质有单体及部分物质的二聚体共29种；糠醛、3-甲基丁醛、2-甲基丁酸乙酯、异戊酸乙酯等可作为5年酒龄猕猴桃酒的特征挥发性物质；苯甲醛可作为4年酒龄猕猴桃酒的特征挥发性物质；乙酸丁酯、乙酸异丁酯、乙酸等可作为3年酒龄猕猴桃酒的特征挥发性物质。PCA和“最近邻”指纹分析结果显示，各组样品分离度良好。GC-IMS技术结合聚类分析方法证明不同酒龄猕猴桃酒所含挥发性物质存在差异，研究结果可为不同酒龄猕猴桃酒的辨识提供一定的思路。     

不同加工方式荣昌猪肉风味差异性评价

为阐明不同加工方式对荣昌猪肉风味的影响,采用电子鼻、电子舌及气相色谱-离子迁移谱联用（gas chromatography-ion mobility spectroscopy,GC-IMS）技术,对蒸制、炒制、烤制、熏制肉及熏制香肠5 种加工类型荣昌猪肉风味进行比较分析。结果表明：利用电子鼻检测结合主成分分析（principal component analysis,PCA）可从挥发性气味方面较好区分蒸制/炒制、烤制、熏制荣昌猪肉风味,且熏制工艺较其他工艺能产生更丰富的风味;利用电子舌技术可从口感方面有效区分5 种不同加工方式荣昌猪肉;利用GC-IMS技术,可通过二维GC-IMS图谱、指纹图谱、PCA等方法快速、直观评价5 种荣昌猪肉风味之间的差异性,蒸制、炒制、烤制荣昌猪肉中正己醇、3-羟基-2-丁酮、戊醛、戊-1-醇、(E)-庚二醛、正辛醛、2-丁酮（二聚体）、2-庚酮（单体）、己醛含量较高;熏制肉和熏制香肠中乙酸乙酯（单体）、α-芹菜烯、α-月桂烯（单体）、3-甲基丁酸、丙酸乙酯、乙酸乙酯（单体）、邻-愈创木酚、芳香醇、对甲基愈创木酚、糠醛、2-甲基丙酸乙酯含量较高;3-甲基丁醛、戊醛是炒制、烤制荣昌猪肉的特征风味物质,糠醛（二聚体）、乙酸乙酯（二聚体）、α-月桂烯（二聚体）、柠檬烯是熏制荣昌猪肉的特征风味物质,乙酸丙酯、糠醛（二聚体）是熏制荣昌猪肉香肠的特征风味物质。     

不同原料酱油抗氧化活性生物测试及风味分析

采用斑马鱼体内抗氧化实验比较了三种不同原料酿造酱油的抗氧化活性,同时采用电子鼻（E-nose）、气相色谱-质谱（GC-MS）结合主成分分析（PCA）分析比较了三种酿造酱油风味特征及风味物质组成。结果表明,黑豆酱油体内抗氧化活性显著高于豆粕和黄豆酱油（P＜0.05）,且其风味特征及挥发性物质组成与黄豆酱油、豆粕酱油均存在较大差异。风味特征差异主要表现为：三者相比氮氧化合物是黄豆酱油特征风味,无机硫化物、W2S醇类、W1S甲基类是豆粕酱油的特征风味,而黑豆酱油特征风味物质主要为杂环类化合物。挥发性风味物质组成差异表现为：黑豆酱油中2-乙酰基吡咯含量较高,豆粕酱油中乙醇和苯乙醛含量相对较高,而黄豆酱油中苯乙醇、4-乙基愈创木酚等重要风味物质相对含量较高。     

6 种安徽地方火腿不同部位特征香气的气相色谱-离子迁移谱表征

采用气相色谱-离子迁移谱（gas chromatography-ion mobility spectrometry,GC-IMS）技术建立6 种安徽地方火腿不同部位特征香气的快速分析方法。结果表明：GC-IMS仪检出107 种挥发性风味物质及其强度信息,但受限于数据库仅鉴定出48 种,包括单体和二聚体;样品中主要的挥发性风味物质包括11 种醇类（正丁醇、正戊醇、正丙醇、2-甲基丙醇、2-己醇等）、9 种酮类（丙酮、2-丁酮、3-羟基-2-丁酮、2-戊酮等）、12 种醛类（正丙醛、异丁醛、正戊醛、异戊醛、正己醛等）、10 种酯类（乙酸乙酯、丙酸乙酯、丁酸乙酯、异戊酸乙酯等）、2 种酸类（正丁酸和异戊酸）及4 种其他成分;采用主成分分析法有效分析了6 种安徽地方火腿不同部位特征香气的相似度,结果表明,不同的猪品种和取样部位之间有较大差异。GC-IMS可用于干腌火腿中挥发性风味物质的快速、全面检测,结合主成分分析可提供火腿品种及品质的信息。     

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