控制热氧化冷榨芝麻油的脂肪酸组成及挥发性

本文采用气相色谱（GC）和固相微萃取-气相色谱-质谱联用（SPME-GC-MS）方法分析了控制热氧化前后冷榨芝麻油的脂肪酸组成和挥发性成分的变化情况。通过相对气味活度值（ROAV）评价各风味物质对芝麻油整体香气的贡献,并结合聚类分析确定控制热氧化后冷榨芝麻油中的关键风味物质。结果显示,样品中的脂肪酸主要有7种,包括3种饱和脂肪酸和4种不饱和脂肪酸,热氧化后冷榨芝麻油中的亚油酸及总不饱和脂肪酸的含量显著降低;柠檬烯和罗勒烯等烃类是冷榨芝麻油中的主要挥发性成分,其含量占风味物质总量的74.6%;热氧化后样品中的挥发性成分增加了10种,总峰面积是冷榨芝麻油风味物质总峰面积的2.68倍,3-甲基丁醛、癸醛、(E,E)-2,4-壬二烯醛、(E,E)-2,4-癸二烯醛等醛类含量高达67.9%,是热氧化样品的主要挥发性成分,其中亚油酸的氧化产物(E,E)-2,4-癸二烯醛是热氧化冷榨芝麻油中最重要的风味物质。     

控制热氧化冷榨芝麻油的脂肪酸组成及挥发性成分分析

本文采用气相色谱(GC)和固相微萃取-气相色谱-质谱联用(SPME-GC-MS)方法分析了控制热氧化前后冷榨芝麻油的脂肪酸组成和挥发性成分的变化情况。通过相对气味活度值(ROAV)评价各风味物质对芝麻油整体香气的贡献,并结合聚类分析确定控制热氧化后冷榨芝麻油中的关键风味物质。结果显示,样品中的脂肪酸主要有7种,包括3种饱和脂肪酸和4种不饱和脂肪酸,热氧化后冷榨芝麻油中的亚油酸及总不饱和脂肪酸的含量显著降低;柠檬烯和罗勒烯等烃类是冷榨芝麻油中的主要挥发性成分,其含量占风味物质总量的74.6%;热氧化后样品中的挥发性成分增加了10种,总峰面积是冷榨芝麻油风味物质总峰面积的2.68倍,3-甲基丁醛、癸醛、(E,E)-2,4-壬二烯醛、(E,E)-2,4-癸二烯醛等醛类含量高达67.9%,是热氧化样品的主要挥发性成分,其中亚油酸的氧化产物(E,E)-2,4-癸二烯醛是热氧化冷榨芝麻油中最重要的风味物质。     

SPME-GC-MS对菜籽毛油和精炼菜籽油挥发性风味成分的分析

以菜籽毛油和精炼菜籽油为原料,采用固相微萃取(SPME)装置顶空取样,用气相色谱-质谱法(GC-MS)对挥发性风味成分进行鉴定.结果表明:菜籽毛油的主要挥发性风味成分为硫甙降解产物、氧化挥发物(醛、醇、酮等)及杂环类物质,其中硫甙降解产物以2-甲代-1-丙烯基-氰、4-甲硫基-丁腈、3-苯基丙腈及4-异硫氰基-1-丁烯为主,氧化挥发物以1,5-己二烯-3-醇和反-2-反-4-癸二烯醛为主要成分,杂环类物质则以吡嗪类化合物为主;精炼菜籽油的挥发性风味成分主要为氧化挥发物,以反-2-反-4-庚二烯醛、反-2-反-4-癸二烯醛、反-2-癸烯醛为主,其菜籽油特征性风味不足,主要源于精炼过程中硫甙降解产物及杂环类芳香物质的减少.     

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。     

HS-SPME-GC-MS结合OAV分析酱油鸡特征风味活性物质的研究

采用顶空固相微萃取(HS-SPME)对酱油鸡的挥发性风味物质进行提取,并利用气相色谱-质谱(GC-MS)联用技术和保留指数(retention index,RI)分离定性。共鉴定出77种挥发性物质,包括烃类18种、醛类19种、醇类13种、酮类7种、酚类5种、酯类5种、酸类4种、醚类2种、杂环类4种。结合气味活性值(odor activity value,OAV)对检出的风味物质进一步筛选,得到1-辛烯-3-酮、辛醛、反,反-2,4-癸二烯醛、反-2-壬烯醛、反,反-2,4-壬二烯醛、丁香酚、肉桂酸乙酯、壬醛、庚醛、糠醛、芳樟醇、己醛、对伞花烃、2-正戊基呋喃、香茅醛这15种"关键风味物质"(OAV≥1)。     

热榨和冷榨胡麻油挥发性物质与关键风味物质组成的分析

采用顶空固相微萃取-气相色谱-质谱联用技术,对比了冷榨和热榨胡麻油中挥发性物质的组成,并结合相对气味活度值法,分析了胡麻油中关键风味物质。结果表明:胡麻油中挥发性物质有醛类、醇类、杂环类、酮类、烷烃类、酸类和酯类,含量最高的是醛类物质,主要是己醛和反式-2,4-庚二烯醛;冷榨和热榨胡麻油醛类物质分别占挥发性物质总含量的40.79%和68.53%,两种胡麻油共有的关键风味物质有壬醛、己醛、反-2-辛烯醛和反式-2,4-庚二烯醛;冷榨和热榨胡麻油挥发性物质中对总体风味贡献最大的分别是壬醛和反式-2,4-癸二烯醛;热榨胡麻油的关键风味物质中还有2,5-二甲基吡嗪和2-戊基呋喃,这两种物质是热榨胡麻油特有的烤香味的来源。     

不同煎炸用油制备河豚鱼汤挥发性风味成分的差异性

采用顶空固相微萃取-气相色谱-质谱联用技术分析不同煎炸用油制备的河豚鱼汤中挥发性风味物质,利用相对气味活度值结合主成分分析确定其特征风味成分。结果表明,不同煎炸用油制备的河豚鱼汤中挥发性风味物质种类与相对含量差别较大,5种不同鱼汤中共检出69种挥发性物质,其中清汤,猪油、大豆油、花生油、橄榄油煎炸后熬煮制得鱼汤分别检测出46、30、38、32、32种。主成分分析能较好地区分不同组鱼汤,清汤的特征风味物质为庚醛、壬醛、癸醛、反-2-癸烯醛、反,反-2,4癸二烯醛、三甲胺;猪油煎炸后熬煮制得鱼汤的特征风味物质为己醛、庚醛、反-2-辛烯醛、壬醛、癸醛、反-2-癸烯醛、反,反-2,4-癸二烯醛、反-2-十一醛、2-戊基呋喃;大豆油、花生油、橄榄油煎炸后熬煮制得鱼汤的特征风味物质为壬醛、癸醛、反-2-癸烯醛、反,反-2,4-癸二烯醛。     

HS-SPME-GC-MS分析4种植物油加热氧化挥发性产物

采用顶空固相微萃取-气质联用法(HS-SPME-GC-MS)对4种脂肪酸组成不同的植物油(棕榈油、菜籽油、葵花籽油和亚麻籽油)在120、150、180℃加热氧化条件下产生的挥发性产物进行分析。结果表明:同种植物油不同温度加热氧化挥发性产物差异不大,不同脂肪酸组成的植物油挥发性产物有明显差异; 4种植物油共有的加热氧化挥发性产物主要有1-辛烯-3-醇、正辛醇、正己醛、2-庚烯醛、壬醛、反-2-辛烯醛、反-2-壬醛、反-2-癸烯醛、2-十一烯醛、反式-2,4-癸二烯醛、甲酸、正戊酸、己酸、庚酸、辛酸、壬酸;在120℃加热氧化36 h时,棕榈油、菜籽油、葵花籽油和亚麻籽油中反式-2,4-癸二烯醛含量分别达到200.64、414.68、579.06、54.72 mg/kg。反式-2,4-癸二烯醛和己酸可作为常见植物油中的特征挥发性物质评价油脂热氧化程度。     

顶空固相微萃取气相色谱质谱联用法分析马油挥发物组成及其腥味物质

目的建立顶空固相微萃取气相色谱质谱联用法分析马油挥发物组成,并初步判断马油主要腥味物质。方法采用顶空固相微萃取(headspacesolid-phasemicro-extractions,HS-SPME)、气相色谱-质谱(gas chromatography-massspectrometry,GC-MS)联用技术,通过单因素与响应面分析,以分离的峰个数和峰面积为考察指标,建立马油挥发性物质的分析方法。根据马脂肪、炼制马油、粗马油和精制马油这4种样品的挥发性成分物质种类的变化,可初步判断马油腥味成分的种类。结果 HS-SPME最佳条件为65μm聚二乙烯苯/聚二甲基硅氧烷(divinylbenzene/polydimethylsiloxane, DVB/PDMS)微萃取头、萃取温度83℃、平衡时间40 min、萃取时间59 min、样品用量4.500 g、解吸时间5 min。确定了43种化合物结构,初步判断己醛、Z-2-庚烯醛、反-2-辛烯醛、壬醛、反-2-壬烯醛、癸醛、反,反-2, 4-壬二烯醛、反-2-癸烯醛、反,反-2, 4-癸二烯醛、2-十一烯醛为马油腥味成分。结论该方法可用于马油挥发性成分的分析,并初步判断马油腥味成分的种类。     

SPME-GC-MS结合GC-O分析糖醋排骨风味香精挥发性风味成分

采用固相微萃取法提取糖醋排骨风味香精中挥发性成分,并结合气相色谱-质谱联用技术和气相色谱-嗅闻技术对萃取成分进行鉴定。结果显示,糖醋排骨风味香精共鉴定出挥发性成分55种,其中烃类11种(16.45%)、醚类3种(13.41%)、醇类10种(12.38%)、其他化合物5种(12.03%)、酮类4种(5.45%)、酯类3种(3.82%)、醛类8种(3.54%)、酸类6种(3.46%)、酚类5种(1.74%)。经气相色谱-嗅闻确定糖醋排骨风味香精中的12种关键性风味成分为β-蒎烯、乙酸、糠醛、2,3,5,6-四甲基吡嗪、苯甲醛、芳樟醇、3-甲基丁酸、反-2-癸烯醛、反-2,4-癸二烯醛、4-羟基-2,5-二甲基-3(2H)呋喃酮、大茴香醛、丁香酚。     

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.     

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.     

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.     

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.