大球盖菇子实体不同部位挥发性成分的比较分析

通过顶空固相微萃取法结合气相色谱-质谱联用方法,对比分析了大球盖菇子实体菌盖和菌柄的挥发性成分,并进行主成分分析（PCA）。结果表明,从大球盖菇子实体菌盖和菌柄都分别鉴定出50种化合物,其中菌盖主要以醇类、酯类和烷类化合物为主,分别占总比例19.93%、19.43%、9.79%;菌柄主要以醇类、酯类和酮类化合物为主,分别占总比例23.04%、21.04%、12.35%。所检测出的化合物中以3,4-二羟基-2-甲基吡啶-5-甲醇、4-哌啶醇、马来酸二乙基己酯、环己烷和3-壬烯-2-酮相对百分含量最高,对大球盖菇香味形成具有重要作用。主成分分析结果显示了醇类化合物为大球盖菇菌盖和菌柄的主要挥发性成分,且菌盖和菌柄在挥发性成分组成上具有明显差异。该研究结果为大球盖菇风味品质评价和大球盖菇品质育种提供了参考。     

HS-SPME-GC-MS结合电子鼻分析烘烤对大球盖菇挥发性风味物质的影响

以大球盖菇为研究对象,利用顶空固相微萃取-气相色谱-质谱（head space-solid phase microextraction-gas chromatography-mass spectrometry,HS-SPME-GC-MS）对挥发性风味物质进行定性定量分析,采用电子鼻区分不同烘烤温度（0、100、120、140、160、180 ℃）处理的大球盖菇挥发性风味物质,结合感官评定评价不同烘烤温度处理的大球盖菇香气特征。结果表明：HS-SPME-GC-MS共鉴定出挥发性风味物质87 种,其中醛类13 种、酯类17 种、醇类18 种、烷烃类4 种、酮类9 种、酸类8 种、吡嗪类4 种及其他类14 种,6 个不同处理的样品中均含有异戊醛、丙位戊内酯等25 种共有成分,烘烤过程中醛类物质、烷烃类物质和吡嗪类物质总含量有所提升,果香、玫瑰香和可可香气增加,醇类物质总含量减少;从整体气味感知来看,电子鼻可以快速有效区分不同烘烤温度处理的大球盖菇挥发性风味;根据相对气味活度值分析出34 种关键风味物质,其中异戊醛对风味贡献最大,具有麦芽香气和水果香气;140 ℃烘烤时生成风味物质种类最多,达到63 种,提高该样品风味的丰富度,增加果香、麦芽香、玫瑰香、坚果香和可可香,使该样品总体风味有所改善;通过感官评定表明烘烤使大球盖菇挥发性风味更为突出,并与上述检测结果一致。     

挂糊油炸大球盖菇菌柄加工过程中挥发性风味物质变化研究

为明确挂糊油炸大球盖菇菌柄在加工过程中的挥发性物质风味变化规律,该文采用顶空固相微萃取结合气相色谱-质谱(headspace solid-phase microextraction gas chromatography-mass spectrometry, HS-SPME-GC-MS)以及电子鼻技术,定性定量分析其在鲜菌柄、挂糊、预炸和复炸4个加工过程共6组样品中挥发性风味物质的差异。结果表明,6组样品共鉴定出166种挥发性风味物质。通过计算相对百分含量和相对气味活度值,发现未油炸样品的挥发性风味物质以醇类和酯类为主,风味贡献最大的物质是1-辛烯-3-酮;油炸后的样品醛类含量占比最大,(E)-2-壬烯醛是风味贡献最大的化合物,并且油炸后风味物质的丰富度明显提高,增加了烤坚果香、巧克力香等香型。主成分分析(principal component analysis, PCA)发现不同加工过程的挥发性风味物质存在较大差异;电子鼻可有效区分油炸前和油炸后样品的挥发性风味物质。该研究从挥发性风味物质角度明确挂糊油炸大球盖菇菌柄加工过程中的风味特征,为大球盖菇的风味研究和拓宽其产品形式提供理论参考...     

不同干制方式对香菇挥发性成分的影响

为研究不同干制方式对香菇挥发性风味物质的影响,运用固相微萃取和气相色谱-质谱联用技术,分别对香菇鲜样及自然、热风、热风联合远红外和远红外四种方式干制的香菇挥发性成分进行分析比较,并结合主要挥发性成分的相对含量和权重值,对香菇干制品进行综合评分。结果表明:鲜香菇、自然干制、热风干制、联合干制、远红外干制分别检测出12、23、27、25、27种化合物。干制方式对香菇中的醇类、酮类、酸类及含硫类挥发性风味成分影响较明显,干制后香菇醇类和酮类化合物均减少,酸类化合物均增加,含硫类化合物除自然干制外含量均大幅增加。热风干制香菇的综合评分最高为7.07,联合干制和远红外干制分别为3.32和2.47,自然干制评分最低为0.20。热风干制因生成较多阈值低的风味物质而能较好的保持香菇风味。     

乳酸菌发酵核桃酸乳不良气味的形成与分析

目的：为探究核桃发酵酸乳不良气味物的形成机制及其组成,改善其风味品质。方法：采用对比实验和感官评价分析不同发酵剂、不同原料组分对发酵乳不良气味产生的影响,研究核桃乳发酵过程中原料组分、羰基价与挥发性化合物的变化规律与相关性;采用顶空-固相微萃取-气相色谱-质谱联用技术分析核桃酸乳挥发性化合物组成,采用相对气味活度值和主成分分析法对关键性风味物和不良气味物进行分析。结果：原料中脂肪组分与不良气味产生显著相关,发酵过程中酸乳羰基价与不良气味形成显著相关;核桃酸乳主要的挥发性风味物包括：己酸等3 种酸类化合物,乙偶姻等3 种酮类物,正己醇等7 种醇类化合物,(E)-2-庚烯醛等4 种醛类化合物以及丁酸丁酯和其他类化合物;相对气味活度值大于1的挥发物为(E)-2-庚烯醛、乙偶姻、己酸、正己醇、正辛醇、1-庚醇、苯甲醛、2-壬酮、2-庚酮、苯乙烯和苯乙醇;关键风味物为乙偶姻、己酸、(E)-2-庚烯醛、正己醇。结论：己酸、(E)-2-庚烯醛、正己醇、苯甲醛为核桃酸乳不良气味的主要风味物,其形成的主要路径为核桃乳发酵过程脂肪水解产生较多的亚油酸、亚麻酸,在脂肪氧合酶作用下氧化,裂解产生C6～C9的醇、醛、酸类物。     

不同贮藏条件下草鱼肌肉挥发性成分的变化分析

为了探讨不同贮藏时期草鱼肌肉挥发性成分的变化情况,采用固相微萃取-气相-质谱联用法(SPME-GC-MS)检测冷藏(0~4℃)及常温(25℃)条件下不同贮藏时间点草鱼肌肉的风味成分组成。本研究共检出9大类物质,主要是醛酮类、醇类、酸类、胺类、烃类及少量其他类化合物,并分析了主要挥发性成分的含量、气味及其可能的来源。研究结果表明,新鲜至冷藏9 d和常温6 h的草鱼肌肉挥发性成分以羰基化合物和醇类为主导风味,且醇类物质含量较多,此时青草味、土腥味明显;冷藏9 d及常温6 h后,酸类、胺类等低阈值物质明显增加,加之醛类物质的作用,此时表现为酸腐味和氨臭味明显;常温贮藏条件下,草鱼肌肉产生特征腐败气味速度更快,即与冷藏相比,腐败更为迅速。     

贮藏温度对大球盖菇采后品质和挥发性风味成分影响

为研究贮藏温度对大球盖菇保鲜效果的影响，以新鲜大球盖菇为试材，于不同贮藏温度（0、15℃）下贮藏12 d，定期取样进行大球盖菇开伞率、腐烂率、失重率、色泽、硬度、咀嚼性及挥发性风味物质的测定。结果表明：15℃下新鲜大球盖菇贮藏期为4～6 d,0℃下贮藏12 d后品质良好。与15℃相比，0℃贮藏能显著降低大球盖菇的开伞率、腐烂率和失重率，更好地维持大球盖菇的硬度、咀嚼性和色泽。0℃贮藏12 d后大球盖菇腐烂率为12.12%，显著低于15℃贮藏组（95.45%,P<0.05）。3-辛醇、1-辛烯-3-醇、反-2-辛烯醛、壬醛、癸醛、3-辛酮、2-戊基呋喃是新鲜大球盖菇的特征风味物质，且3-辛醇和己醛是大球盖菇采后品质劣变的关键挥发性风味成分。与15℃贮藏组相比，0℃贮藏组大球盖菇电子鼻响应值更低，正己醇、己醛、壬醛等不良风味成分的相对气味活度值更低，并且挥发性风味物质种类更多。因此，0℃贮藏能有效保持大球盖菇的采后品质，抑制其风味劣变。     

白猪肉与黑猪肉热反应香精中香气物质分析鉴定

以黑猪肉和白猪肉酶解物及氧化脂肪为原料,经热反应制备肉味香精。溶剂辅助蒸发结合气相色谱-质谱联机分析挥发性风味物质,基于保留指数、质谱共鉴定出123种挥发性化合物,包括含硫化合物、含氮杂环、含氧杂环、醛类、酮类、醇类、酸类、酯类、烃类等。相比之下,白猪肉香精中烷基呋喃、脂肪族醛和酸的相对含量较高,黑猪肉香精中含硫化合物、含氮杂环、酯类化合物的相对含量较高,而醇类、酮类化合物的相对含量二者相差不大。采用气相色谱-嗅闻分析,基于质谱、保留指数、气味特征、标准品共鉴定出31种气味活性化合物,28种为2种肉味香精所共有,尤其二甲基三硫、糠硫醇、3-乙基-2,5-二甲基吡嗪、3-甲硫基丙醛、2-乙基噻吩、(E,E)-2,4-癸二烯醛、(E)-2-癸烯醛、(E)-2-壬烯醛、1-辛烯-3-醇、3-羟基-2-丁酮等在两香精中均具有较高稀释因子。但黑猪肉香精中具有高稀释因子的化合物种类多于白猪肉香精,且采用雷达图对强势气味活性化合物比较显示其肉香、脂香化合物的轮廓线大于白猪肉香精,这可能是造成黑猪肉香精香气较浓的原因。     

基于GC-MS和电子鼻技术分析不同烘烤度橡木对荔枝白兰地风味的影响

为了研究不同烘烤度橡木片对荔枝白兰地陈酿风味的影响，在荔枝白兰地中加入不同烘烤度橡木片进行陈酿。运用感官评价、电子鼻和气相色谱-质谱联用，对四种(原酒、轻度烘烤、中度烘烤和重度烘烤)荔枝白兰地的品质和挥发性风味成分进行评定和分析。结果表明，在四种荔枝白兰地中共检测出21种挥发性香气化合物，其中酯类和醇类物质在四种酒中皆有，气味活度值较高，对酒的风味贡献大，它们的组成与含量构成了荔枝白兰地的主要挥发性香气特征。原酒中含有独特的烯烃类和芳香烃类化合物，不同烘烤橡木浸渍的荔枝白兰地中含有独特的醛酮类物质。原酒中风味化合物种类最多，含量较高。轻度和中度烘烤橡木荔枝白兰地中风味化合物种类较少，主要是酯类、醇类和醛酮类，而重度烘烤橡木荔枝白兰地中则含有部分烯烃和芳香烃类化合物。在感官评价中，重度烘烤橡木荔枝白兰地得分最高，风味较好，同时电子鼻检测可以明显的区分出添加不同烘烤度橡木的荔枝白兰地，因此添加重度烘烤的橡木片能提升荔枝白兰地陈酿的品质。     

基于SPME-GC-MS和电子鼻分析薏苡仁油加速氧化过程挥发性成分变化

采用固相微萃取-气相色谱-质谱联用和电子鼻技术分析薏苡仁油氧化期间风味化合物动态变化。结果表明：薏苡仁油加速氧化期间特征挥发性风味物质主要为醛类、酮类、醇类化合物。新鲜油中相对气味活度值大于1的关键挥发性成分贡献度从大到小依次为(E)-2-壬稀醛、(E,E)-2,4-癸二烯醛、(E)-2-癸烯醛、(E,Z)-2,6-壬二烯醛、1-辛烯-3-酮、癸醛,赋予青草气味、油脂味、西瓜样品味;随着氧化时间的延长油脂品质劣变,60 ℃加速氧化30 d时醛类化合物相对含量为73.815%,与新鲜油相比,小分子醛、酸及醇类化合物相对含量增加;薏苡仁油加速氧化后关键风味化合物新增壬醛、辛醛、己醛、(E)-2-辛烯醛,赋予其酸败气味;电子鼻线性判别分析明显区分新鲜油与氧化油以及氧化初期及后期风味物质差异。结果表明(E)-2-壬稀醛、(E,E)-2,4-癸二烯醛等为新鲜薏苡仁油的特征化合物,壬醛、辛醛、己醛等小分子化合物为薏苡仁油加速氧化后的特征化合物。     

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.     

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.     

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 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.