内生真菌对葡萄干提取物生物转化影响的GC-MS分析

利用从茶树中分离的1株经鉴定为黑孢霉属的内生真菌EFTI-01在优化的条件下对葡萄干提取物进行生物转化,采用GC-MS联用仪分析葡萄干提取物中2种重要的香料物质2,3-二氢-3,5二羟基-6-甲基-4H-吡喃-4-酮和5-羟甲基糠醛转化前后含量的变化。结果表明:生物转化能显著提高葡萄干提取物中2种物质的含量,不同处理方法,其转化效率有显著差异,采用从EFTI-01提取粗酶液对葡萄干提取物进酶转化后,2,3-二氢-3,5二羟基-6-甲基-4H-吡喃-4-酮和5-羟甲基糠醛的含量最高提升了3.0倍和3.2倍,以EFTI-01的活菌丝对葡萄干提取物进行生物转化后这2种物质含量最高分别提升了87.7倍52.3倍。     

基于烟草水提物的Maillard反应产物影响因素

为充分利用烟叶资源,提高其使用价值,以亚临界萃取后的烟叶残渣为原料制备了烟草水提物,利用GC-MS法对Maillard反应产物进行定量分析,系统探讨了氨基酸种类及用量、反应时间对Maillard反应产物化学组成及卷烟感官质量的影响;并探讨了Maillard反应产物中的18种成分与卷烟感官指标的相关关系。结果表明:①谷氨酸和天冬氨酸的Maillard反应产物与水提物自身的Maillard反应相似,以5-羟甲基糠醛为主,其次为羟基丙酮、2-乙酰基吡咯;脯氨酸参与的反应产物则以羟基丙酮、糠醇和5-羟甲基糠醛为主。②以感官作用为依据,基于烟草水提物Maillard反应的最佳条件为还原糖（以葡萄糖计）与谷氨酸的摩尔比n_还原糖:n_谷氨酸=1:0.5、反应温度110 ℃、反应时间2 h。③18种成分中,2-甲基四氢呋喃-3-酮与烟气浓度相关关系密切,糠醛、5-甲基糠醛、2-呋喃基羟基甲基酮和5-羟甲基糠醛与透发性关系密切,羟基丙酮和3-甲基-1, 2-环戊二酮与烘焙香关系密切。      

基于雪茄烟叶残渣的美拉德反应香料制备及应用

目的:解决烟草提取物生产过程中产生的烟叶残渣再利用难题。方法:以雪茄烟叶残渣制备的水提物为原料,研究了氨基酸用量、反应时间对Maillard反应产物化学组成及卷烟感官质量的影响;并探讨了Maillard反应产物中的18种成分与卷烟感官指标的相关关系。结果:(1)以感官为依据,基于雪茄烟草水提物Maillard反应的最佳条件为：水提物10.00 g、天冬氨酸0.74 g、谷氨酸0.08 g、葡萄糖0.50 g,温度110℃,反应时间3.0 h。(2)与水提物相比,Maillard反应产物中5-羟甲基糠醛、羟基丙酮、糠醛、5-甲基糠醛、2-乙酰基吡咯、2,5-二甲酰基呋喃等的含量显著增加。(3) 18种化合物中,2-乙酰基呋喃与细柔显著相关,3-羟基-2-丁酮、3-乙酰基吡啶与奶香显著和极显著相关,2-呋喃基羟基甲基酮、5-羟甲基糠醛和2,3-二氢-3,5-二羟基-6-甲基-4(H)-吡喃-4-酮与花香显著或极显著相关,而6-乙基-5,6-二氢-2H-吡喃-2-酮与杂气、刺激、苦味、干草香指标均显著负相关。结论:烟草水提物经Maillard反应处理后,香气特征成分含量增加,在卷烟中应用能起...     

利用白玄参提取物制备烟用美拉德反应香料的研究

采用复合酶对白玄参进行酶解提取,将酶解液浓缩,外加氨基酸进行美拉德反应制备烟用香料。通过正交试验确定最适反应条件为:白玄参酶解液2 g,葡萄糖2.5 g,脯氨酸和赖氨酸1.25 g(二者质量比为2︰1),初始pH 9.0,反应时间6 h,反应温度95℃。评吸结果表明,最优工艺条件下得到的美拉德反应香料能显著增加卷烟的"津"、"甜"吃味,降低刺激性。通过GC-MS分析其致香物质,得到21种新生成的挥发性致香成分,其中吡嗪、呋喃和吡咯等杂环类美拉德特征香味成分15种,2,3-二氢-3,5-二羟基-6-甲基-4H-吡喃-4-酮(DDMP)的含量可达305.69mg/L。     

云南烤烟种植海拔与致香成分的相关性分析

为了研究种植海拔对烤烟致香成分的影响,采用同时蒸馏萃取-气相色谱/质谱法对云南烟区1 300～2 300 m范围内不同海拔高度采集的256个初烤烟叶样品中的致香成分进行了分析,应用SPSS统计软件对海拔高度与烟叶致香成分含量间的相关性进行了探索.结果表明:(1)上部烟叶中的致香成分糠酸、氧化异佛尔酮、十四酸含量与种植海拔之间呈显著的正相关;(2)中部烟叶中的致香成分3-甲基-2(5H)-呋喃酮、2-环戊烯-1,4-二酮、3,4-二甲基-2,5-呋喃二酮含量与种植海拔之间呈显著的负相关;(3)无论是上部烟叶还是中部烟叶,其致香成分中的酯类物质含量与烟叶种植海拔间均呈显著的正相关关系.     

不同采收成熟度烤后烟叶香气质量评价

以不同采收成熟度初烤烟叶为试验材料,采用感官评吸、电子鼻无损检测和气质联用法3种方式对烤后烟叶香气质量进行评价,分析不同处理烟叶的香气质量特征及主要致香成分的贡献,探索电子鼻评价烟叶香气质量的新方法。结果表明：7-8成黄采收的烤后烟叶评吸质量显著优于8-9成黄采收的烤后烟叶,但与6-7成黄采收处理无明显差异。气质联用法检测出的新植二烯含量与感官评吸结果吻合度较好,新植二烯可能对整体香气质量起主导作用。类胡萝卜素降解产物中的5,6-环氧紫罗兰酮、2-甲基-2-庚烯-6-酮和异佛尔酮,苯丙氨酸类降解产物中的苯甲醛、苯甲醇和4-乙烯基-2-甲氧基苯酚,美拉德反应产物中的5-甲基糠醛、吡嗪、3-甲基-2-环戊烯-1-酮,其他类致香物质中的γ-丁内酯等致香物质可能是影响不同成熟度烤后烟叶香气质量的关键成分。电子鼻可以初步判定不同处理烤烟的整体香气质量,对不同样品鉴别度较高。电子鼻检测可以作为一种有效评价烟叶整体香气质量的方式辅助烟叶感官评吸,提高香气质量评价的可靠性。     

烤烟致香成分与香气质量的相关性分析

采用数据挖掘方法中的Wrapper特征提取法得到显著影响烤烟香气质量的关键指标,并与简单相关系数结论进行对比。结果表明,影响香型的主要是香叶基丙酮、戊酸、酸性总量、巨豆三烯酮、茄酮等20种致香成分;影响香气量的主要是香叶基丙酮、2-乙酰吡咯、四甲基吡嗪、苯甲醛、茄酮、异戊酸、β-大马酮等25种致香成分;影响香气质的主要是巨豆三烯酮、异戊酸、茄酮、中性总量、新植二烯、香叶基丙酮、法尼基丙酮、4-甲基戊酸、2-甲基吡嗪、β-大马酮、吡啶等18种致香成分。经过特征提取后所建立的致香成分与香气质量的模型性能有较大地提高,并且RBF神经网络模型比分段线性回归模型的预测精度更高。     

烙铁温度对成品烟丝致香成分的影响

建立了顶空—固相微萃取/气相色谱—质谱(HSSPME/GC-MS)联用法分析不同烙铁温度对同一规格不同批次卷烟中试试样烟丝样品中致香物质的组成及含量的影响。结果表明:①两个批次的成品烟丝共检测出35种核心致香成分,其中批次X含30种,批次Y含34种;②3-甲基-3-丁烯-2-酮、2-己烯-1-醇、2-(丁氧基乙氧基)乙醇、棕榈酸甲酯、3,5-二甲基苯酚为批次X未检测出成分,3-甲基-1,2-环戊二酮为批次Y未检测出成分,1,2-丙二醇为含量最高的致香物质;③F检验表明X、Y两个批次样品中致香成分含量的差异是来自于烙铁温度,将烙铁温度控制在270℃更利于保留烟丝中的致香成分。     

白肋烟中一些重要碱性成分和羰基化合物的分析研究

本文对3个地区白肋烟中的一些重要碱性成分和羰基化合物进行了分析研究。采用同时蒸馏萃取的前处理方法和配备氮-磷检测器的气相色谱仪及气质联用仪对重要的碱性香味成分进行了分析鉴定,共鉴定出41种碱性化合物;并采用内标法对白肋烟中的吡啶、2-甲基吡嗪、2,6-二甲基吡嗪、2-乙酰基吡啶等17种重要的碱性香味成分进行了定量测定。采用甲醇超声波振荡提取的前处理方法和气相色谱仪及气质联用仪对醛酮类致香物进行了分析鉴定,共鉴定出46种醛酮类致香物;定量测定了2-戊酮、2,3-戊二酮、6-甲基-5-庚烯-2-酮、6-甲基-3,5-庚二烯-2-酮、糠醛等27种香味物质。研究结果表明:从碱性香味成分总量来看,巴西白肋烟样品 > 四川白肋烟样品 > 湖北白肋烟样品;从羰基类致香成分总量来看,湖北白肋烟样品 > 四川白肋烟样品 >巴西白肋烟样品。      

酶解对鸡骨素美拉德反应挥发性风味成分的影响

为了探索酶解对鸡骨素美拉德反应香精挥发性风味成分的影响,采用固相微萃取/气相色谱-嗅闻-质谱(SPME/GC-O-MS)技术对清汤型和白汤型鸡骨素美拉德反应产物(清汤MRPs1和白汤MRPs1)及鸡骨素酶解液美拉德反应产物(清汤MRPs2和白汤MRPs2)中的挥发性风味成分进行比较分析。在4种产物中共鉴定出 70种挥发性化学成分,清汤MRPs1中29种,MRPs2中50种;白汤MRPs1中38种,MRPs2中53种。与 MRPs1 相比,MRPs2 中醛酮、杂环类化合物的浓度显著增加(p<0.05)。白汤MRPs2的醛酮类物质种类更多,反-2-壬烯醛、2-十一碳烯醛、反-2-癸烯醛、反,反-2,4-癸二烯醛、3-羟基-2-甲基-4-吡喃酮、6-甲基-5-庚烯-2-酮等特征香气成分只在白汤骨素中检出。但是在清汤MRPs2中杂环类物质则更加丰富,例如2-乙酰基呋喃、2,5-二甲基-3-乙基吡嗪、3,5-二甲基-2-乙基吡嗪、2-甲基-3,5-二乙基吡嗪、3,6-二甲基-2-异戊基吡嗪等则只在清汤骨素中检出。酶解对鸡骨素美拉德反应产物中的挥发性风味成分的种类和浓度有相当大的影响,增加了终产物的烤香、脂香和肉香,使整体风味更加浓厚饱满。     

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.     

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.     

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