不同发酵方式的泡菜挥发性成分分析

为研究不同发酵方式泡菜中挥发性成分的差异,采用顶空固相微萃取结合气相色谱-质谱联用技术对自然发酵、老泡菜水发酵、肠膜明串珠菌发酵、植物乳杆菌发酵和短乳杆菌发酵5 种不同发酵方式的泡菜及泡菜原料中挥发性成分进行检测分析,得到不同种类化合物共55 种。利用相对气味活度值确定了各类泡菜及原料中的主体风味成分的种类。结果表明,不同泡菜中的主体风味成分种类差异较大,仅壬醛是各类泡菜的共有主体风味成分,对结球甘蓝泡菜风味影响最大。通过主成分分析结果可知,老泡菜水发酵、短乳杆菌发酵和甘蓝原料的风味在整体上明显不同,而肠膜明串珠菌、植物乳杆菌发酵泡菜与自然发酵泡菜在总体风味成分上较为接近,并与壬醛、异硫氰酸烯丙酯、右旋萜二烯关联较大。     

功能菌对泡菜风味物质形成的影响

以分离于自然发酵泡菜中的植物乳杆菌和酵母菌作为功能菌强化发酵制作泡菜;并研究功能菌对泡菜风味物质形成的影响。采用高效液相色谱法、顶空固相微萃取-气质联用技术对发酵泡菜中有机酸和挥发性香气成分进行分析检测,研究酵母菌不同接种量对泡菜风味物质的影响。结果表明:酵母菌接种量为0.5%时,泡菜中风味物质较多;自然发酵泡菜风味与人工接种功能菌发酵泡菜风味差异较大,不同发酵时间和接种量的泡菜风味物质的种类和含量也有所差异,发酵过程中共检出6种有机酸和41种挥发性成分,其中有机酸中草酸、乳酸含量较高,挥发性成分中酯类、醇类、酚类以及二甲基硫化物相对含量较高,是白萝卜泡菜的特征风味成分。     

四川泡菜挥发性成分及主体风味物质的研究(二)

以四川泡菜为研究对象,运用固相微萃取与气相色谱质谱联用法(SPME-MS/GC),分析鉴定自然发酵泡菜、老盐水发酵泡菜和直投式功能菌剂发酵泡菜的风味成分构成,确定了挥发性成分中醇、醛、酮、烯等占挥发性成分总量的90%,对挥发性成分的相对风味活度进行判定,确定了影响泡菜的主体风味物质为二甲基硫化物、烯类、醛类,而酯类物质对四川泡菜的风味成分影响微乎其微;自然发酵泡菜风味与老盐水发酵泡菜、直投式功能菌剂发酵泡菜差异较大,老盐水发酵泡菜与直投式功能菌剂发酵泡菜主体风味成分相近。     

乳酸菌菌种差异对泡菜发酵风味的影响

本论文对自然发酵和纯种发酵的大白菜泡菜在发酵过程中的乳酸菌多样性及风味品质进行了研究,结果表明:乳酸菌Lactobacillus plantarum、L.brevisvis、L.acidophilus和L.helveticus是泡菜自然发酵过程中的优势菌群;泡菜中主要的挥发性风味成分为酯类、酸类、醇类、酮类、烯烃类等,纯种发酵泡菜样品中风味物质的种类和含量均不及自然发酵;泡菜中的有机酸有草酸、酒石酸、苹果酸、乳酸、乙酸、柠檬酸、琥珀酸等,自然发酵中的草酸和柠檬酸含量均高于纯种发酵。     

贵州米酸汤发酵过程中风味品质的研究

通过HS-SPME-GC-MS技术对贵州米酸汤发酵过程中的挥发性风味成分进行测定,并结合理化指标及主成分分析,探究其风味品质的变化。研究发现贵州米酸汤的风味物质组成丰富,发酵过程中共计检出109种挥发性风味成分,其中酸、酯类是主体物质;米酸汤挥发性成分随发酵时间的延长而增加,不同发酵时期对挥发性组分影响不一。发酵0~1d为米酸汤发酵的初期,风味成分变化显著,酸、酮、醛、呋喃类物质降低,醇、酯类物质增加,总相对含量从83.941%增加到96.716%;发酵1~10d为米酸汤发酵的产酸阶段,风味成分组成稳定,仅出现1.322%增减幅度;发酵10~15d为米酸汤风味的成型阶段,酮、呋喃、烃、酚、醛、醇及酸类物质的含量明显提高,各物质复合形成米酸汤的独特风味。通过主成分分析发现,醛类、酸类、酯类、酮类、呋喃类物质对发酵10d及15d的米酸汤影响较大,酚类、醇类、烯烃类、烷烃类物质对发酵0d及1d的米酸汤影响较大,各阶段米酸汤的风味品质差异显著,发酵15d的米酸汤风味品质最佳。     

凯里白酸汤发酵过程中挥发性风味物质的变化

采用顶空固相微萃取技术(HS-SPME)和气相色谱-质谱(GC-MS)联用技术,分析白酸汤发酵过程中各类挥发性风味物质的动态变化规律,并利用主成分分析法对挥发性风味物质进行评价。实验结果表明,发酵过程中共检测出40种挥发性风味成分,包括9种酸类、13种醇类、4种酯类、4种醛类、3种酮类、1种酚类和6种萜烯类;酸类、醇类、酯类和萜烯类物质占主导地位,其相对含量占总挥发性化合物的98%以上。发酵过程中,酸类、醇类、酯类、醛类的种类数量和相对含量随发酵进行缓慢增加;酯类、酚类和萜烯类物质的相对含量先增加后降低。主成分分析得到22种主要的挥发性风味物质,发酵第3天时白酸汤的综合得分最高,风味最佳。     

泡菜发酵过程挥发性风味成分的变化

采用SPME–GC–MS对泡菜在发酵过程中不同时期的挥发性风味进行分析。结果表明:泡菜的最佳食用期为48 h,不同时期的泡菜的挥发性成分差异明显;共鉴定出化合物111种,包括醇类、烃类、含硫化合物、酯类、醛类、酮类、酸类等。泡菜在发酵期间,酸类、醇类、含硫化合物的含量不断增长;在发酵后期,烃类、醛类、酮类化合物的含量不断下降。含硫化合物和醇类对泡萝卜的风味形成有较大贡献。     

传统四川泡菜中挥发性成分分析

采用顶空固相微萃取(headspace solid phase micro-extraction,HS-SPME)结合气相色谱-质谱联用(gas chromatograph-mass spectrometry,GC-MS)技术对不同原料的传统四川泡菜中挥发性成分进行检测、分析。结果表明:5种原料泡菜中共检出化合物80种。不同原料泡菜中检出的挥发性成分差异较大,泡萝卜、泡芥菜、泡甘蓝、泡黄瓜、泡芹菜中分别检出化合物38、23、24、22、24种。酯类、醛类、酮类、醇类、萜类、芳香族化合物、含硫化合物及杂环化合物对泡菜风味形成具有重要影响。其中酯类是泡萝卜、泡芥菜和泡甘蓝中的特征挥发性成分,醛类、萜类分别是泡黄瓜、泡芹菜的特征挥发性成分。泡芥菜和泡甘蓝中异硫氰酸烯丙酯含量最高,泡萝卜、泡黄瓜、泡芹菜中含量最高的风味物质分别是中1-异硫代氰酸丁、反式-2,6-壬二烯醛、右旋萜二烯。对四川泡菜独特风味形成具有重要作用的风味物质是异硫氰酸戊酯、异硫氰酸苯乙酯、苯甲醛、壬醛、癸醛、右旋萜二烯和萘。     

红曲菌发酵对番石榴叶活性及风味成分的影响

采用红曲菌（Monascus anka） GIM 3.592进行番石榴叶固态发酵转化,增强番石榴叶活性成分,改善番石榴叶风味。探讨添加谷物种类、番石榴叶粉碎度及基质含水量等对红曲霉发酵转化功能成分的影响,并考察发酵对番石榴叶挥发性成分的影响。结果表明,发酵番石榴叶可以提高活性物质含量,其中总黄酮含量为23.1 mg/g,总酚含量为40.23 mg/g及槲皮素含量为1.30 mg/g,比原番石榴叶分别提高了60.8%、48.1%、202.3%。同时,发酵转化使番石榴叶中具有刺激气味的植物醇和β-石竹烯下降,并增加具有淡淡茶香味的6-芹子烯-4醇和杜松烯等风味物质含量,使发酵番石榴叶的风味得到较大改善。     

不同发酵剂对泡萝卜挥发性风味成分及感官品质的影响

该文以白萝卜为原料发酵泡萝卜，探究了6种发酵剂对泡菜的挥发性风味成分和感官品质的影响。对不同发酵剂发酵的泡萝卜的挥发性成分进行定性和半定量分析，利用聚类分析法探究挥发性成分与菌种相关性，采用闪现剖面(flash profile, FP)法比较腌制萝卜的品质差异。研究发现，不同发酵剂发酵的泡萝卜共检出75种挥发性成分，包括酯类12种、醇类27种、萜烯类5种、酸类10种、醛酮类4种、烷烃类4种和其他13种，不同的发酵剂发酵泡萝卜所含各类组分的含量和占比均不同。挥发性成分与菌种相关性分析结果表明6种发酵剂菌种与挥发性成分之间具有较大的差异，且真菌和细菌产生的挥发性成分的物质组成也具有较大差异。植物乳杆菌、耐酸乳杆菌和沙雷氏菌是发酵过程中主要细菌组成，毕赤酵母是发酵过程中的主要真菌组成，与醇类、酯类、酸类和萜烯类化合物显著正相关(P<0.01)。感官评价结果表明不同发酵剂发酵的泡萝卜的挥发性成分可被明显区分，感官分析结果与挥发性成分测定结果重合度较高。综合实验结果，HS发酵剂发酵的泡萝卜挥发性风味成分表现较优，并且该发酵剂发酵的泡萝卜感官品质较好。     

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.     

An internet compendium of analytical methods and spectroscopic information for monomers and additives used in food packaging plastics

An internet website (http://cpf.jrc.it/smt/) has been produced as a means of dissemination of methods of analysis and supporting spectroscopic information on monomers and additives used for food contact materials (principally packaging). The site which is aimed primarily at assisting food control laboratories in the European Union contains analytical information on monomers, starting substances and additives used in the manufacture of plastics materials. A searchable index is provided giving PM and CAS numbers for each of 255 substances. For each substance a data sheet gives regulatory information, chemical structures, physico-chemical information and background information on the use of the substance in particular plastics, and the food packaging applications. For monomers and starting substances (155 compounds) the infra-red and mass spectra are provided, and for additives (100 compounds); additionally proton NMR are available for about 50% of the entries. Where analytical methods have been developed for determining these substances as residual amounts in plastics or as trace amounts in food simulants these methods are also on the website. All information is provided in portable document file (PDF) format which means that high quality copies can be readily printed, using freely available Adobe Acrobat Reader software. The website will in future be maintained and up-dated by the European Commission's Joint Research Centre (JRC) as new substances are authorized for use by the European Commission (DG-ENTR formerly DGIII). Where analytical laboratories (food control or other) require reference substances these can be obtained free-ofcharge from a reference collection housed at the JRC and maintained in conjunction with this website compendium.     

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.     

Analysis of benzo[a]pyrene in spiked fatty foods by second derivative synchronous spectrofluorimetry after microwave-assisted treatment of samples

A simple, rapid and inexpensive method has been developed for the determination of benzo[a     

The development of reference materials for paralytic shellfish poisoning toxins in lyophilized mussel. II: Certification study

This paper describes the second part of a project undertaken to develop certified mussel reference materials for paralytic shellfish poisoning toxins. In the first part two interlaboratory studies were undertaken to investigate the performance of the analytical methodology for several PSP toxins, in particular saxitoxin and decarbamoyl-saxitoxin in lyophilized mussels, and to set criteria for the acceptance of results to be applied during the certification exercise. Fifteen laboratories participated in this certification study and were asked to measure saxitoxin and decarbamoyl-saxitoxin in rehydrated lyophilized mussel material and in a saxitoxin-enriched mussel material. The participants were allowed to use a method of their choice but with an extraction procedure to be strictly followed. The study included extra experiments to verify the detection limits for both saxitoxin and decarbamoyl-saxitoxin. Most participants (13 of 15) were able to meet all the criteria set for the certification study. Results for saxitoxin.2HCl yielded a certified mass fraction of <0.07 mg/kg in the rehydrated lyophilized mussels. Results obtained for decarbamoyl-saxitoxin.2HCl yielded a certified mass fraction of 1.59+/-0.20 mg/kg. The results for saxitoxin.2HCl in enriched blank mussel yielded a certified mass fraction of 0.48 +/- 0.06 mg/kg. These certified reference materials for paralytic shellfish poisoning toxins in lyophilized mussel material are the first available for laboratories to test their method for accuracy and performance.     

Announcing a new international peer-reviewed journal:Food Science and Human Wellness now accepting manuscript submission in English

<正>We are pleased to announce the launch of a new international peer-reviewed journal-Food Science and Human Wellness,ISSN 2213-4530,which is an open access journal,produced and hosted by Elsevier B.V.on behalf of Beijing Academy of Food Sciences.Food Science and Human Wellness is an international peer-reviewed English journal that provides a forum for the dissemination of the     

Chinese CTP Market

According to Printing and Printing Equipment Industries Association of China（PEIAC）＇s statistics to the plate manufucturer in China, in 2013, the actual offset plate production has reached 346 million square meters in China. Among them, the CTP production volume was 245 million square meters, up by 11% than that of last year; the total sales of the CTP plate was 239 million square meters, up by 13%.     

Preparatory Work of Print China 2015 is Going Smoothly

正Held at Guangdong Modern International Exhibition Center,Print China 2015 will cover 7exhibition halls,besides the original Hall No.3,4,5,6,7,the newly built F zone of Hall 3 will be used too.The total area will be140,000 square meters.Hall 3:Offset and large printing equipment,package printing equipment,post press