烤烟复烤片烟在济南自然陈化期间化学成分含量变化

研究了8个产区14个烤烟复烤烟叶样品自然陈化7～51个月期间烟叶总糖、还原糖、烟碱和总氮含量变化,结果表明,随着陈化时间增加,总糖、还原糖、烟碱和总氮含量逐步降低;南方产区糖降低幅度高于北方产区,上部烟叶糖含量下降幅度高于中部烟叶;总氮对陈化期间感官质量变化影响最大。     

烤烟不同基因型间质体色素含量差异与烟叶化学成分的关系

研究了烤烟不同基因型间质体色素含量差异及与烟叶化学成分的关系。结果表明,不同烤烟基因型烟叶中质体色素含量差异显著。相关分析结果发现,叶绿素a仅与总糖呈显著性正相关;叶绿素b与烟碱呈显著性负相关,与总氮含量呈极显著性负相关;类胡萝卜素与总糖呈显著性负相关,但与烟碱和总氮含量呈显著性正相关。通径分析结果表明,叶绿素a和叶绿素b对总糖、烟碱和总氮的直接影响最大,类胡萝卜素对总糖、烟碱和总氮的间接影响最大。由此可见,通过对烤烟质体色素代谢进行合理调控,有利于协调烤烟化学成分,提高烟叶的可用性。     

2002-2013年间我国烤烟主要化学成分变化趋势及原因分析

为了提高我国烟叶的工业可用性,采用2002-2013年间烤烟主产区中部叶数据,分析了近年来我国烤烟主要化学成分指标的变化趋势并探讨了其原因。结果显示,我国烤烟中部烟叶烟碱、总氮、还原糖、钾、氯和淀粉含量(质量分数)范围分别为1.38%~3.77%、1.35%~2.96%、16.96%~32.76%、1.09%~3.07%、0.11%~0.79%和2.00%~8.07%。2002-2013年间,我国烤烟中部烟叶淀粉、钾和氯含量在不同年份间相对稳定,还原糖含量由2002年的21.79%上升为2013年的26.54%,以2005-2008年间上升明显;平均烟碱含量则由2002年的2.72%下降为2013年的2.29%,以2003-2007年间下降明显;总氮变化趋势与烟碱相似;烟草种植布局和品种格局变化与化学成分变化关系不大,烤烟还原糖含量的升高与除北方烟区外其他烟区还原糖含量的普遍升高密切相关,烟碱和总氮含量的降低则主要与西南、东南和长江中上游烟区烤烟烟碱和总氮含量的降低有关。      

烤烟成熟期土壤水分状况对烟叶挥发性香气物质及主要化学成分的影响

为研究烤烟成熟期间不同阶段控水处理对烤烟香气及主要化学成分的影响,采用盆栽,分别在烤烟叶片处于定长、欠熟、适熟3个阶段将土壤相对含水率控制在40%和80%,测定烟叶挥发性香气成分及主要化学成分的含量.结果表明:烤烟成熟过程中,短时干旱处理后西柏烷类物质、质体色素降解物、美拉德反应产物和芳香族等香气物质含量比对照高,而持续干旱处理时这些物质含量比对照低,越临近烟叶定长的干旱对香气物质含量影响越大;烤烟成熟期间,任意阶段较短时间的干旱对香气物质形成有利,但持续干旱对香气形成不利.打顶后的间断干旱,水溶性糖和还原糖含量升高,总氮和烟碱含量也升高,欠熟期、适熟期干旱和整个成熟期干旱能使钾含最稍微升高.     

土壤养分与烤烟化学成分含量间的关系

采用描述统计、相关分析和典型相关分析方法研究了烟叶基地烤烟叶片化学成分含量与土壤养分含量之间的关系,结果表明:①烟叶基地土壤养分含量总体处于富足状态,但各烟区的土壤养分肥力不均匀,烟叶钾含量偏低,蛋白质含量偏高;②土壤有机质与土壤碱解氮,烟叶烟碱、总氮、蛋白质含量分剐呈显著正相关,与烟叶总糖、还原糖含量分别呈显著负相关;土壤pH值与烟叶烟碱、总氮、蛋白质含量分别呈显著负相关,与烟叶总糖、还原糖含量分别呈显著正相关.③在一定范围内土壤中的碱解氮、速效磷、速效钾、有机质含量的增加与烟叶烟碱、总氮、蛋白质、钾含量的增加一致,土壤中速效钾、pH值的增加与烟叶总糖、还原糖含量的增加一致.土壤水溶性氯和烟叶中氯含量的增加是一致的.     

两种典型环境对烤烟香型风格及致香物质的影响

通过人工控制土壤水分、UV-B辐射强度、气温及昼夜温差,模拟我国中部低海拔烟区和西南高海拔烟区的生态因素,研究环境对烤烟香型风格及香气前体物、致香成分等的影响。结果表明,成熟期高温和适度缺水能促进叶片内含物的分解,类胡萝卜素的田间降解更加彻底,烤后烟叶中苯丙氨酸降解产物和棕色化反应产物含量较高,浓香型风格更加显著。当环境中UV-B辐射较强、成熟期昼夜温差较大时,烟叶内含物积累较丰富,成熟后香气前体物含量增加,烤后烟叶中质体色素降解产物和类西柏烷类降解产物含量较高,棕色化反应产物含量较低,烟叶香型风格表现为中间香。     

河南烤烟化学成分与烟气成分的相关性分析

对河南不同产地、津巴布韦和巴西产的烤烟烟叶烟气中的焦油、烟气烟碱、CO等有害成分的释放量进行了检测和分析,并对化学成分中的还原糖、总氮、烟碱、K2O、Cl-、SO24-及有机钾对焦油、烟气烟碱、CO的影响进行了相关性分析.结果表明河南烤烟烟气的焦油、烟气烟碱、CO量均高于津巴布韦、巴西烤烟,上述烟气成分与烟叶的K2O、有机钾、还原糖/烟碱、K/Cl呈显著负相关;与烟碱、Cl-和SO24-则为显著正相关;与还原糖比较,上部叶呈显著负相关,中部叶和全部样品相关性不明显.     

湖北烤烟主要化学成分年度间稳定性分析

采用统计分析方法,对湖北烟区18 个植烟县的2005-2009 年共计234 个初烤烟叶B2F、C3F、X2F 样品的主要化学成分进行了稳定性分析。结果表明：（1）湖北烤烟化学成分平均值基本都在优质烟的适宜值范围内,总糖、还原糖、总氮的变异较小,氯、钾氯比、糖碱比的变异较大。（2）湖北烤烟主要化学成分变异性在各年度表现不同,各年份各部位等级烟叶主要化学成分含量变异不同。总体来看,年度内氯、两糖差的变异较大,总氮、还原糖、总糖的变化较小。（3）湖北烤烟B2F 等级年度间总糖、总氮、钾、氮碱比、糖碱比达到极显著差异;烟碱、钾氯比达到显著差异。C3F 等级年度间总糖、总氮、氮碱比、糖碱比、钾氯比达到极显著差异;烟碱、氯达到显著差异。中上部烟叶的烟碱呈下降趋势,钾含量呈上升趋势。X2F 等级年度间总糖、总氮、钾、糖碱比、钾氯比达到极显著差异;烟碱、氯、氮碱比达到显著差异。     

低烟碱品种及栽培模式对烤烟化学成分及感官质量的影响

  目的  为研究低烟碱品种结合低烟碱栽培模式对烟碱的降低效果及其他烟叶化学成分和烟叶质量的影响。  方法  在河南省许昌市,以常规品种中烟100、低烟碱品种ITB687和超低烟碱品种NC926为材料,设置当地常规栽培模式（LCCP）和低烟碱栽培模式（LNCP）进行栽培试验。  结果  （1）不同品种在LCCP下农艺性状差异较小,而LNCP模式对其生长后期影响较大,叶片长宽比增加,上部叶面积和单叶重显著下降。（2）在LCCP下3个品种的生物碱含量差异极大,NC926上部叶和中部叶调制后烟碱含量分别为0.28%、0.21%。LNCP显著降低烟叶烟碱和总生物碱含量,但低烟碱品种在LNCP下烟碱降幅相对较小,其中NC926上部叶调制后烟碱含量降低38.03%,中部叶无显著差异;高烟碱品种采用LNCP降低幅度相对较大,其中中烟100上部叶和中部叶调制后烟碱含量分别降低44.11%、30.01%。（3）在LCCP下不同品种同一部位烤后烟的还原糖、总糖、总氮含量均表现为中烟100 > ITB697 > NC926,LNCP下烟叶总氮含量降低,上部叶还原糖、总糖含量增加,但中部叶还原糖、总糖含量降低。（4）在LCCP下不同品种中性香气成分含量以及经济性状无显著差异,LNCP下烟叶中性香气成分总量减少,香气质变差,香气量、浓度、劲头和刺激性减小,余味变淡,同时烟叶经济性状变差。  结论  通过遗传育种途径可选择性大幅降低生物碱含量,采用低烟碱栽培模式虽可使烟碱含量进一步降低,但对烟叶质量和效益会产生显著负面影响。      

烤烟烟叶香气质量与其常规化学成分的相关性

对2004年44个国产和2个进口烤烟烟样的烟碱、总氮、还原糖、钾、氯、淀粉、总挥发碱和总挥发酸及其燃吸质量进行了检测,并对所获得的数据作偏相关分析。结果表明:①2个进口烤烟烟样烟碱、总氮、还原糖、钾、氯、淀粉和总挥发碱的含量均位于或稍偏离适宜指标范围,而44个国产烤烟烟样有50%以上烟样的烟碱含量偏高、钾和总挥发碱含量偏低,所有国产烤烟烟样的总挥发酸含量低于2个进口烤烟烟样;②烤烟烟叶样品的总挥发酸含量与其香气质、香气量极显著正相关,而其烟碱、总氮、还原糖、钾、氯、淀粉、总挥发碱含量与其香气质、香气量的相关性不显著。     

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.     

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.     

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.     

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.     

Contribution of European research to risk analysis

The European Commission's, Quality of Life Research Programme, Key Action 1—Health, Food & Nutrition is mission-oriented and aims, amongst other things, at providing a healthy, safe and high-quality food supply leading to reinforced consumer confidence in the safety of European food. Its objectives also include the enhancing of the competitiveness of the European food supply. Key Action 1 is currently supporting a number of different types of European collaborative projects in the area of risk analysis. The objectives of these projects range from the development and validation of prevention strategies including the reduction of consumers risks; development and validation of new modelling approaches; harmonization of risk assessment principles, methodologies, and terminology; standardization of methods and systems used for the safety evaluation of transgenic food; providing of tools for the evaluation of human viral contamination of shellfish and quality control; new methodologies for assessing the potential of unintended effects of genetically modified (genetically modified) foods; development of a risk assessment model for Cryptosporidium parvum related to the food and water industries; to the development of a communication platform for genetically modified organism, producers, retailers, regulatory authorities and consumer groups to improve safety assessment procedures, risk management strategies and risk communication; development and validation of new methods for safety testing of transgenic food; evaluation of the safety and efficacy of iron supplementation in pregnant women; evaluation of the potential cancer-preventing activity of pro- and pre-biotic ('synbiotic') combinations in human volunteers. An overview of these projects is presented here.     

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.