生物酶法降解烟梗末中果胶的研究

通过青霉产果胶酶降低烟梗末中的果胶的含量,从而提高梗末作为原料薄片工艺中的使用性能。首先通过正交实验确定了酶解的最佳条件为加酶质量分数6%,料液比1 g∶3 m L,酶解温度50℃,酶解时间2 h,果胶酶的最大降解率为38.92%。然后经热重分析表明,梗末经果胶酶降解后,最后的残重从24.46%下降至9.84%,说明酶解后的梗末的燃烧性得到提升。最后,利用热裂解-气相色谱/质谱联用分析酶解前后梗末的热裂解产物,发现酶解后裂解产中的乙酸含量降低,香味物质吡咯含量升高,这将有助于改善烟草薄片的吸食口感,本研究中为提高造纸法烟草薄片的品质提供了一个新的方法。     

类芽孢杆菌发酵原料浸提液提升再造烟叶品质

为提升再造烟叶品质,利用烟草中分离的类芽孢杆菌制备静息细胞,对再造烟叶原料浸提液进行发酵处理;采用连续流动分析、气质联用仪（GC-MS）、热裂解-气相色谱质谱（Py-GC/MS）等方法,测定了发酵过程中浸提液中蛋白质、还原糖、氨基酸含量变化;分析了其主要挥发性香味成分;并利用发酵浸提液浓缩涂布制备再造烟叶样品,进行热裂解产物分析和感官评价。结果表明:①发酵浸提液和对照组中的蛋白质、还原糖含量在5 h内持续减少,而氨基酸含量先增高后降低,且发酵浸提液的蛋白质、还原糖含量低于对照,氨基酸含量高于对照;②发酵液中香味物质种类和总量较对照组均有所增加,其中糠醛、糠酮等致香组分增幅明显;③对比再造烟叶裂解产物,发现发酵浸提液浓缩后涂布样品裂解产生的γ-丁内酯、2,3-二氢-5-甲基呋喃、糠醛等典型烟气致香组分提高;④发酵液浓缩后涂布的再造烟叶样品感官品质较对照样品明显提升。利用类芽孢杆菌发酵烟草浸提液,对于提升再造烟叶的感官品质具有促进作用。      

生物制备全烟草组分再造烟叶及结构特性分析

为开发高性能加热卷烟用再造烟叶,利用烟草生物发酵获得的细菌纤维素(BC)及其发酵过程中的烟草浸提液和烟草滤渣,混合制备了基于全烟草组分的BC重组再造烟叶; 并将其与市售3种典型加热卷烟再造烟叶进行了对比,从外观形貌、微观结构、主要化学成分、热重性能、热裂解香味产物等方面进行了系统分析。结果表明:①BC重组再造烟叶具有良好的成型性,样品外观均匀,物理指标与市售产品中稠浆法再造烟叶接近; ②对比市售3种典型再造烟叶,BC重组再造烟叶具有相似的红外吸收特征峰,但是扫描电镜显示,BC重组再造烟叶结构致密,BC纤维直径分布在43.68~75.80 nm之间; ③BC重组再造烟叶总吸热量最大,为9.52 J·g-1; ④BC重组再造烟叶的水溶性总糖含量为6.17%,烟碱含量达13.17 mg·g-1,热裂解释放香味物质种类高达45种,其中酮醛类致香物质释放量明显高于对比样品。      

造纸法再造烟叶生产过程中梗膏提质酶技术的应用研究

造纸法再造烟叶产品中大分子物质的含量直接影响产品抽吸品质。用离子色谱结合紫外分光光度计等仪器分析烟梗提取液中纤维素、果胶、蛋白质、淀粉的含量,利用生物酶的专一性特点,对烟梗提取液进行酶解转化处理,通过分析各种单一酶对烟梗提取液中大分子物质的降解情况,确定单一品种生物酶用量,在此基础上,对生物酶进行复配,复配生物酶用于再造烟梗提取液中大分子物质的降解,结合现行生产工艺条件,对烟梗提取液中大分子物质的降解进行一定程度控制,为生产过程中烟梗提取液的提质奠定一定的理论依据。     

卷烟焦油中性香味物质的分离和鉴定

为了解国外某些卷烟的香味成份和加香物质,对香气类似而焦油量不同的两种外国卷烟 A(代号)和 B(代号)的焦油香味物质做了对比分析研究,以溶剂萃取,柱层析、薄层层析,气相色谱,液相色谱和减压蒸馏等多种方法进行分离分析,对两种烟样焦油中性物柱层析集分进行了评吸和气相色谱分析比较,发现其相应集份的香气特征与 GC 色谱图相似,表明他们的香味物质组成基本相同。当两种烟样以等焦油量比较时,焦油含量较低的卷烟 B 的 GC 色谱图有部分色谱峰显著高于卷烟A。推测这些峰成分为卷烟 B 通过加香和调整烟叶配方而增加的香味物质,称这些成分峰为“特征峰”。对两种烟样焦油中性物柱层析某些有较好香味的重点集份做了 GC/MS 试验,共鉴定出115种物质成分,其中包括10种“特征峰”成分。所鉴定的物质中,许多为前人已确定的烟草香味物质,部分是前人未鉴定或发表过的。     

真空回潮工序对造纸法再造烟叶的质量影响

采用对比方式,分析造纸法再造烟叶经真空回潮处理前后的感官质量、加工质量以及掺配成品烟支的烟丝结构、物理指标、化学指标、感官质量的变化趋势.结果表明:经真空回潮处理后的造纸法再造烟叶吸食品质稍有提升,但香味物质损失较大;经过真空回潮处理的再造烟叶对成品卷烟烟丝结构、理化指标和感官质量的影响不明显.     

复合造纸法再造烟叶的制备及效果分析

为提高造纸法再造烟叶的感官质量,提出了一种复合造纸法再造烟叶的制备方法.结果表明,采用双网复合纸机制备复合造纸法再造烟叶是可行的,所制备的再造烟叶感官质量达到了国外造纸法再造烟叶先进企业同档次产品的水平;在一类卷烟品牌中使用5%的复合造纸法再造烟叶,可使卷烟焦油量降低0.7 mg/支,且不影响卷烟感官质量.     

UV照射对低次烟叶中性香味物质和常规化学成分的影响

为提高低次烟叶的有效利用率,对其进行了紫外(UV)辐射处理,并采用同时蒸馏萃取-GC/MS法分析了UV处理烟叶中的香味物质的成分及变化;测定了处理前后各个样品的总糖、总氮和烟碱。结果表明:UV照射使烟叶内部的醇类、酯和内酯类香味物质的含量增加,酚类香味物质含量显著降低,醛类、呋喃类、氮杂环类和西柏烷醇类含量均在照射60 min时达到最高值。     

一株产木质素降解酶真菌在造纸法再造烟叶中的应用

为了降低烟梗的木质素含量、节约造纸法再造烟叶生产过程中的能耗,提高再造烟叶品质,将1株可以产生木质素降解酶的真菌C2进行液体培养,测定木质素过氧化物酶、锰过氧化物酶和漆酶的活性变化.将发酵液过滤得到粗酶液,按5%施加量处理烟梗,测定干质量和木质素含量变化,将烟梗打浆并制备造纸法再造烟叶.结果显示,3种木质素降解酶分别在第6, 8, 16 d达到最高活性;粗酶液处理后可以降低烟梗强度,干质量和木质素含量均降低;在造纸法再造烟叶中可以节省10%的打浆时间,产品杂气降低,余味改善.     

不同类型的加热卷烟原料性能比较

  目的  为开发适用于加热卷烟烟支用原料,掌握不同制造工艺原料的物理化学特性的区别。  方法  通过收集不同的加热卷烟原料样品,采用光学显微镜法、差示扫描量热法（Differential Scanning Calorimetry, DSC）、热重红外联用（TG-IR）和裂解气相色谱质谱联用（Py/GC-MS）分析了加热卷烟原料叶丝结构及热性能。  结果  ① 光学显微镜照片显示加热卷烟用原料烟叶叶丝表面湿润,辊压法和稠浆法再造烟叶丝结构紧密,干法造纸法造纸法叶丝结构呈多孔疏松,湿法造纸法再造烟叶丝纤维结构明显,结构略疏松;②热性能分析表明叶丝、辊压法和稠浆法再造烟叶丝在50℃~400℃温度区间吸热量为（1023±150）J/g、（1280±200）J/g和（1190±180）J/g,较其它再造烟叶丝样品低,吸热量小反映了样品需要较少的外源能量即可达到目标温度;③热重红外联用和裂解气相色谱质谱联用结果表明不同工艺下的加热卷烟原料逸出气体的主要成分差别不大,主要为甘油、二氧化碳和烟碱等,稠浆法样品相较其它样品而言,在200℃~400℃下物质释放更稳定。  结论  烟丝、辊压法和稠浆法再造烟叶丝较干法和湿法再造烟叶丝结构更为致密,单位质量升高相同温度时吸热量更低,在烟支制造过程中提高发烟段原料填充量及节约加热烟具能量等方面具有优势。      

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