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。     

顶空固相微萃取-气质联用法分析稻谷挥发性成分

用顶空固相微萃取(HS-SPME)技术结合气相-质谱法(GC-MS)对不同稻谷中挥发性成分进行研究,优化顶空固相微萃取的条件,包括平衡时间、萃取时间、萃取温度以及样品量,并对不同稻谷中挥发性成分进行鉴定和分类分析。结果表明：稻谷中挥发性成分分析的最佳条件为平衡时间60min、萃取时间50min、萃取温度80℃、样品量20g。稻谷中的挥发性成分有醇类、醛类、酮类、酯类、烃类、有机酸类以及杂环类化合物等。最主要挥发性成分是醛类,其中含量最高是己醛,平均为13.31%;其次为壬醛,平均为7.93%。     

SPME/GC-MS对4种超微粉碎杂粮粉中挥发性成分分析

通过固相微萃取-气质联用(SPME/GC-MS)的方法对4种经过超微粉碎技术获得的杂粮(青稞、荞麦、红豆和薏苡)粉中的挥发性成分进行研究,在最优条件下进行检测分析。结果表明,最佳SPME条件为萃取温度80℃、平衡时间10 min、萃取时间40 min、解析时间180 s;GC-MS共检测到并鉴定出的挥发性成分共127种,其中杂环类和其他化合物(92.2%)含量最高,其次是酯类(53.8%)、苯环类(41.8%)化合物。它们共有的挥发性风味物质有11种,分别是壬醛、癸醛、(Z)-6,10-二甲基-5,9-十一碳烯-2-酮、棕榈酸甲酯、棕榈酸乙酯、正十二烷、环十四烷、3’-甲氧基-2,2’-二硝基苯乙炔、2,6-二叔丁基对甲酚、1-甲基萘、2,3-二甲基萘。     

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30/50 μm DVB/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 该方法可较好区分正常油菜籽与霉变油菜籽。     

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。     

SPME和P&T对西瓜汁香气成分萃取条件优化及二者的比较分析

为了充分萃取西瓜汁的香气成分,避免萃取方法及条件对西瓜汁香气成分分析的影响,本研究优化了前处理方法中PT的时间和温度、SPME中的萃取纤维、温度和时间,并将这两种方法的萃取效果进行了比对分析。研究表明,PT的平衡温度50℃、吹扫时间30min能达到最佳的萃取效果;SPME优化的最佳萃取条件是:CAR/DVB/PDMS纤维、平衡温度40℃、平衡时间40min。这两种方法的对比研究表明,SPME对西瓜汁的萃取效果明显优于PT。     

烤制鹌鹑蛋挥发性成分SPME条件优化

以鹌鹑蛋为原材料,研究了烤制鹌鹑蛋挥发性成分的固相微萃取(SPME)条件.通过单因素和正交实验对萃取头种类、样品萃取量、萃取时间、萃取温度以及解吸时间进行优化.结果表明,较佳的萃取条件为:DVB/CAR/PDMS萃取头,萃取时间为30min,萃取温度为65℃,样品萃取量为2g,解析时间为2min.在此条件下,检测到烤制鹌鹑蛋中的挥发性成分34种.     

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。     

SPME-GC-MS分析与鉴别青海亚麻籽油挥发性组分

以青海不同产地的40种亚麻籽为原料,索氏抽提提取亚麻籽油,采用顶空固相微萃取结合气相色谱-质谱联用对亚麻籽油挥发性组分进行分析,通过优化搅拌速率、萃取温度、平衡时间、萃取时间、解吸时间、升温程序确定最佳固相微萃取条件及GC-MS条件。结果表明,采用DVB/CAR/PDMS萃取头,亚麻籽油SPME最佳条件为磁力搅拌速率400 r/min,萃取温度80 ℃,平衡时间20 min,萃取时间40 min,解吸时间5 min,在该萃取条件下可以检测出青海40种亚麻籽油挥发性成分共58种,醛类12种,酸类8种,醇类9种,酮类2种,酯类5种,烷烯类13种,杂环类3种,其他类6种,分离鉴定效果较好;根据聚类分析,醛类物质是将亚麻籽油样品进行区分的主要挥发性组分,该结果为亚麻籽油品质鉴定及开发利用提供了理论依据。     

SPME-GC-MS法鉴定养殖大黄鱼主要挥发性风味物质的条件优化

以养殖大黄鱼为研究对象,对其主要挥发性风味物的SPME-GC-MS分析条件进行优化,通过不同的固相微萃取条件的选择、GC-MS条件优化和样品处理的研究,结果表明,SPME-GC-MS最佳分析条件为:大黄鱼样品量5.00g,NaCl添加量5.0%(0.25g),气相程序升温速率8℃/min,选用DVB/CAR/PDMS萃取头,萃取温度70℃,萃取时间30min,平衡时间20min,解析时间5min。     

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.     

The Ministry of Environmental Protection Issued "Feasible Technology Guidelines for Pollution Prevention and Control in Wood Pulping Process of the Paper Industry (Trial)" and Two Other Guiding Technical Documents

On December 27t＂, 2013, the Ministry of Environmenta Protection announced that, in order to implement ＂The Environmental Protection Law of the People＇ s Republic of China＂, improve the working system in environmenta protection technologies, and promote technologica advancement in pollution prevention, the Ministry of Environmental Protection sponsored the formulation of three guiding technical documents including ＂Feasible Technology Guidelines for Pollution Prevention and Contro n Wood Pulping Process of the Paper Industry （Trial）＂     

1~(st) Intelli-Tissue~ EcoEc Tissue Machine Supplied by PMP Group Successfully Put into Operation in China

正On April 29th,2014,Intelli-Tissue EcoEc tissue machine supplied by PMP Group successfully put into operation at Hebei Xuesong Paper Co.,Ltd.,this is the first such kind of paper machine of PMP Group in China.