卷烟燃烧过程中烟丝形态结构变化的表征方法

为了研究卷烟燃烧过程中烟丝形态结构变化对烟气释放的影响,从烟丝的微观结构、燃烧锥平面结构等方面,建立了表征卷烟燃吸过程中烟丝形态结构变化的新方法,并探讨了卷烟燃吸过程中烟丝形态结构变化对主流烟气CO释放量的影响。结果表明:(1)烟丝形态结构发生变化的特征温度为300~350℃。在该温度区间内,烟丝的宽度和厚度均出现了显著的收缩,同时烟丝整体发生卷曲;(2)通过对包埋固定后的燃烧锥进行切片,获得了燃烧锥长度及面孔率等燃烧锥结构的表征参数;(3)烟丝宽度从0.6 mm增至1.4 mm,卷烟燃烧锥长度变短,面孔率增加,单位质量烟丝的CO释放量降低17.42%;(4)烟丝长度从大于4.0 mm降低至小于1.6 mm,卷烟燃烧锥长度变短,面孔率增加,单位质量烟丝的CO释放量降低16.73%。     

烟叶中游离态和结合态有机酸含量分析

  目的  烟叶中有机酸是卷烟香气质量和风格特征的重要组成部分,本文的目的是考察烟叶中不同形态有机酸含量差异。  方法  采用调整pH值后萃取然后硅烷化-GC-MS/MS测定的方法,测定33种有机酸的游离态和盐类结合态总量。采用皂化然后硅烷化-GC-MS/MS测定的方法,测定有机酸游离态、有机酸盐类和酯类的总量。  结果  ① 所建方法测定了烟叶中33种有机酸的皂化总量和萃取量,回收率、日内及日间精密度较好、灵敏度高;②部分有机酸皂化前后含量变化很大,其中2-甲基丁酸、3-甲基戊酸、4-甲基戊酸皂化总量为萃取量的10倍以上,说明这些酸在烟叶中主要以酯的形式存在;③四种类型烟叶中（烤烟、白肋烟、香料烟、晒红烟）,香料烟的短链脂肪酸皂化总量是最高的,且皂化总量与萃取量比值均大于50（除己酸外）。烤烟中长链脂肪酸和其他有机酸皂化总量最高,且皂化总量与萃取量比值均大于5。      

卷烟燃烧锥面孔率与主流烟气CO释放量的关系

为了研究卷烟燃烧过程中形成的燃烧锥结构与主流烟气CO释放量之间的关系,采用包埋切片法考察了卷烟燃烧锥的内部结构,分析了卷烟燃烧锥面孔率变化影响烟气CO释放量的机理,并通过调节燃烧锥结构降低了主流烟气CO释放量。结果表明:(1)卷烟燃烧锥的面孔率与CO释放量呈显著的负相关关系,燃烧锥面孔率越大,燃烧锥结构越疏松,烟丝燃烧越充分,主流烟气CO总释放量越低;(2)降低烟丝的填充密度、添加低比例的膨胀烟丝均可使燃烧锥面孔率增加和烟气CO释放量降低;(3)在常规卷烟样品中添加1%的可膨胀石墨,可有效调节燃烧锥结构,燃烧锥面孔率从18.25%增大至35.60%,主流烟气CO释放量降低12.30%,卷烟危害性指数从7.31下降至7.01。     

烟叶产地与部位对卷烟主流烟气焦油和7种有害成分释放量的影响

为考察国内烟叶产地及烟叶部位对卷烟主流烟气焦油和7种有害成分释放量的影响,选取国内代表性烟叶产区不同部位烟叶样品467个,卷制成单料烟并测试烟气焦油、7种代表性有害成分和烟碱释放量,研究了烟叶产地和部位对卷烟主流烟气焦油、卷烟危害性评价指数(H)、7种代表性有害成分及烟碱释放量的影响。结果表明:(1)烟叶产地对NNK的单位燃烧烟丝质量释放量影响最大,其次为氨、HCN和苯酚等3种成分,对焦油、烟碱、H、B[a]P、巴豆醛、CO等指标影响较小。(2)烟叶产地对氨和NNK的单位烟碱释放量影响最大,其次为HCN、巴豆醛、B[a]P、苯酚和CO等5种成分,对焦油和H影响较小。(3)烟叶部位对氨、烟碱、苯酚、NNK等4种成分的单位燃烧烟丝质量释放量影响显著,对焦油、H、HCN、B[a]P、巴豆醛、CO等指标影响较小。(4)烟叶部位对巴豆醛、CO、NNK、B[a]P和HCN等5种成分的单位烟碱释放量影响显著,对焦油、H、氨和苯酚等指标影响较小。通过调控卷烟配方中烟叶的产地和部位,有助于降低烟气中焦油、7种有害成分的单位燃烧烟丝质量释放量或单位烟碱释放量。     

再造烟叶丝、膨胀烟丝和膨胀梗丝的燃烧特性

为了解再造烟叶丝、膨胀烟丝和膨胀梗丝的燃烧特性,利用锥形量热仪研究了三者在燃烧过程中热释放、烟气释放、质量损失、CO和CO2释放等关键燃烧特征参数的变化。结果表明:①膨胀梗丝的易燃性差于再造烟叶丝和膨胀烟丝;②在有焰燃烧阶段,膨胀烟丝较再造烟叶丝和膨胀梗丝具有更快速的烟气释放速率,而在阴燃阶段,膨胀烟丝的烟气释放速率明显低于再造烟叶丝;③在整个燃烧过程中,膨胀梗丝的发烟量均小于膨胀烟丝和再造烟叶丝。在阴燃阶段,再造烟叶丝的发烟量高于膨胀烟丝;④在阴燃状态下再造烟叶丝、膨胀烟丝和膨胀梗丝的CO释放速率都明显高于有焰燃烧阶段,CO2释放速率则相反;在整个燃烧过程中,膨胀梗丝较膨胀烟丝和再造烟叶丝生成了更多的CO和更少的CO2。     

不同长度、圆周、切丝宽度卷烟主流烟气常规指标释放量及其变化

为评价不同烟支长度、圆周及切丝宽度对卷烟主流烟气化学成分释放量的影响,以3种切丝宽度的单一叶组配方制备的5种圆周、4种长度的卷烟为研究对象,分析了ISO抽吸模式下的主流烟气常规指标,并考察了其单位焦油、单位烟碱、单位燃烧烟丝质量释放量的变化规律。结果表明:(1)切丝宽度和烟支圆周相同时,卷烟主流烟气各常规指标的实测值随烟支长度增大而增加;但烟气常规指标的单位焦油释放量无明显差异。(2)在圆周23.0～27.0 mm范围内,卷烟主流烟气总粒相物(TPM)和焦油的单位烟碱释放量随烟支长度的增大而逐渐降低;且随烟支圆周的增大,负相关的趋势越明显。(3)切丝宽度和烟支圆周一定时,TPM、焦油、水分和CO的单位燃烧烟丝质量释放量随烟支长度的增大总体上呈下降趋势。(4)切丝宽度一定时,TPM、焦油、水分和CO的单位烟碱释放量和单位烟丝质量释放量在5种烟支圆周条件下,均在100 mm烟支长度时出现最小值。(5)烟支圆周和烟支长度与焦油释放量均极显著正相关,而切丝宽度与焦油显著负相关。     

烟丝含水率对主流烟气CO等7种有害成分释放量的影响

为考察烟丝含水率对主流烟气CO等7种有害成分释放量的影响,采用3种饱和盐溶液制备了不同烟丝含水率的卷烟,分别收集3组卷烟的烟气总粒相物、测定主流烟气中CO等7种有害成分的释放量,并对卷烟的物理参数和固相燃烧温度进行了检测。结果表明:①烟丝含水率对7种有害成分的释放量影响不尽相同,随着烟丝含水率的升高,卷烟主流烟气中氨(NH3)、4-(甲基亚硝胺基)-1-(3-吡啶基)-1-丁酮(NNK)、苯酚的释放量呈降低趋势,CO,苯并[a]芘(B[a]P)释放量呈升高趋势,氢氰酸(HCN)及巴豆醛的变化不明显;②烟丝含水率对卷烟的固相燃烧温度没有显著影响,但影响卷烟的燃烧速率(燃烧过程),进而影响了烟气成分的形成、转移和释放。     

烟草生物质燃烧特性与机理研究

为研究烟草生物质的燃烧行为与燃烧特性,采用热重-差示扫描量热联用(TG-DSC)方法,分析了4种典型烟草生物质(烤烟中部叶丝、膨胀梗丝、膨胀烟丝和再造烟叶)在5,10,15和20Ⅱ/min升温速率下的燃烧过程。结果表明:1烟草生物质燃烧过程中存在挥发分着火和固定碳着火两次着火现象;2较高升温速率(15和20Ⅱ/min)下膨胀烟丝存在挥发分和部分固定碳共燃的现象;3通过对烟草生物质综合燃烧特性指数的计算,发现4种烟草生物质在较低升温速率(5和10Ⅱ/min)下燃烧特性差异不大,在较高升温速率(15和20Ⅱ/min)下膨胀烟丝的燃烧特性最好。     

MTBSTFA衍生化结合GC-MS分析镇江香醋不挥发羧酸

以镇江香醋为研究对象,利用N-特丁基二甲基硅烷基-N-甲基三氟乙酰胺(N-(tert-butyldimethylsilyl)-N-methyltrifluoroacetamide,MTBSTFA)衍生化结合气相色谱-质谱法(GC-MS)分离鉴定香醋中不挥发羧酸,共鉴定并定量61种不挥发化合物,包括17种氨基酸、13种芳香酸、11种羟基酸、8种长链脂肪酸、7种二元及多元酸(不含羟基)、1种含硫有机酸、1种酮酸,2种杂环酸和1种不挥发酸酯。新检测到2-糠酸、乙醇酸、3-羟基丙酸、甘油酸、扁桃酸、对羟基苯乙酸、2,6-二羟基苯甲酸、原儿茶酸、阿魏酸、柠檬酸、芥子酸、没食子酸、咖啡酸等24种不挥发有机酸。研究结果表明,香醋中羟基酸(16.01 g/L)含量最高,其次是杂环酸(597. 3 mg/L)和氨基酸(546. 5 mg/L);单个酸含量大于100 mg/L的有乳酸、焦谷氨酸、琥珀酸、精氨酸、草酰乙酸和2-羟基-3-苯丙酸(从高到低依次)。该研究将为我国食醋品质的提升奠定基础。     

烟丝含水率对细支卷烟的影响

考察了烟丝含水率对细支卷烟烟支物理性能、烟支内部烟丝结构分布、烟支静燃速率、抽吸时燃烧锥落头率、卷烟主流烟气释放和感官质量的影响。结果表明,细支卷烟烟丝含水率为11.5%~13.8%,在卷烟单重一致的情况下,烟丝结构分布、卷烟抽吸时燃烧锥落头率以及感官抽吸品质受烟丝含水率影响大。烟丝含水率增大,烟丝抗造碎性能增强,烟支中大尺寸烟丝所占比例增加,烟末减少,卷烟抽吸时燃烧锥落头现象明显减轻;烟丝含水率从11.5%增加到12.9%,燃烧锥落头率可从65%降低至30%。烟丝含水率过高会导致卷烟烟气浓度减小,满足感降低。此外,烟丝含水率增大,细支卷烟的烟支硬度、烟支静燃速率、烟气焦油和烟碱释放量也会发生细微的变化。综上,建议细支卷烟生产过程中烟丝含水率尽量控制在12.5%~12.9%。     

造纸法再造烟叶原料提取过程中有机酸的溶出规律

为研究多级水提取对造纸法再造烟叶原料中有机酸的提取效果,采用气相色谱-质谱联用法测定了碎烟片(简称烟片)原料和各级滤渣中主要挥发性、半挥发性和非挥发性有机酸的含量(质量分数)。结果表明:①原料和各级滤渣中有机酸的含量存在明显差异,随着提取级数的增加,滤渣中挥发性和非挥发性有机酸总量减小,半挥发性有机酸的总量增加。原料和滤渣中的有机酸以草酸、苹果酸和柠檬酸为主,3种酸总量随提取级数的增加而减小。②滤渣中半挥发性有机酸和草酸的含量均高于其在烟片原料中的含量。采用多级水提取方法有利于烟叶原料中多数有机酸成分的提取,但并不能将烟片原料中半挥发性有机酸和草酸有效提取出来。      

烟草中有机酸分析研究进展

较全面地综述了近 5 0年来国内外烟草中有机酸的分析研究进展 ,并对烟草中各种有机酸如挥发、半挥发和不挥发酸的性质、含量、前处理方法包括溶剂萃取、水蒸气蒸馏和甲酯化等 ,以及分析仪器的发展与局限性进行了比较 ,认为改进现有方法 ,开发新方法 ,使烟草中有机酸的分析过程更简便、快速 ,分析结果更准确 ,是今后烟草有机酸分析的重要研究课题。     

Rumen fermentation in vitro as influenced by long chain fatty acids

Responses of rumen microbes to fatty acids were evaluated by production of total volatile fatty acid and ratio of acetate to propionate. Fermentations were under carbon dioxide for 20 h in 50-ml Erlenmeyer flasks in a Dubnoff metabolic shaking incubator. Flasks contained 20 ml medium, 1 ml reducing solution, 750 mg substrate (450 mg hay plus 300 mg grain), and varying amounts of long-chain fatty acids supplied as free acids, as calcium salts, or as triglycerides. They were inoculated with 5 ml rumen fluid obtained from a cow fed 3.6 kg grass hay, 2.3 kg grain, and .2 kg tallow daily. Volatile fatty acid production was decreased by long-chain fatty acids that contained less than 18 carbon atoms and by unsaturated long-chain fatty acids with 18 carbon atoms. Lauric acid decreased volatile fatty acid production by 69% and induced unusual acetate/propionate ratio (40:1). Stearic acid, however, did not affect volatile fatty acid production or acetate/propionate ratio. Within two series of long chain fatty acids (myristic, palmitic, stearic, arachidic; stearic, oleic, linolenic), melting point accounted for 93 to 95% of the variation of volatile fatty acid production and acetate/propionate. As calcium salts, long chain fatty acids caused small changes of fermentation. Our data support the proposition that hard fats and calcium salts of long-chain fatty acids do not interfere with ruminal fermentation.     

烟叶多元酸和高级脂肪酸分析及其对感官品质的影响

为明确湖南烟区烟叶原料多元酸和高级脂肪酸含量及其与感官品质的关系,采用非衍生化方法的气相色谱法对湖南烟区3个区县,不同部位的7种烟叶样品的多元酸和高级脂肪酸含量进行检测,发现7种烟叶原料,多元酸中丙酸含量最高,其次是3-甲基戊酸和2-甲基丁酸,高级脂肪酸中十六酸含量最高,再次是亚油酸和油酸;同时发现,这些多元酸和高级脂肪酸在上部烟叶中的含量高于中部烟叶;采用偏最小二乘回归分析(PLSR)方法对烟叶中多元酸和高级脂肪酸含量与感官品质相关性进行了分析。结果表明,多元酸含量越高,提香越明显,口腔刺激感越低且透发性越强,而高级脂肪酸仅仅可以提高烟叶抽吸劲头,但不利于其他感官指标。     

响应面优化脂肪酶催化合成中长碳链甘三酯

采用响应面设计对脂肪酶Novozym 435在无溶剂体系中催化甘油和中长碳链脂肪酸(辛酸、癸酸和油酸混合物)酯化反应合成中长碳链甘三酯进行了研究.研究发现:反应温度、加酶量和反应时间对中长碳链甘三酯得率具有显著性影响(P＜0.05),而底物摩尔比(脂肪酸与甘油摩尔比)对中长碳链甘三酯得率不具有显著性影响.优化得到的最佳条件为:反应温度90℃,加酶量6.5％(以脂肪酸和甘油的总质量计),底物摩尔比3.5∶1,反应时间12.97 h.在此条件下,平均甘三酯得率为78.5％;产品中甘三酯、甘二酯、甘一酯和游离脂肪酸含量分别为85.6％、0.3％、0.1％和14.0％;产品甘三酯中辛酸、癸酸和长碳链脂肪酸含量分别为25.4％、10.7％和63.9％,与目标中长碳链甘三酯产品指标基本一致.     

Genetic correlations of mid-infrared-predicted milk fatty acid groups with milk production traits

The objective of this research was to estimate the genetic correlations between milk mid-infrared-predicted fatty acid groups and production traits in first-parity Canadian Holsteins. Contents of short-chain, medium-chain, long-chain, saturated, and unsaturated fatty acid groupings in milk samples can be predicted using mid-infrared spectral data for cows enrolled in milk recording programs. Predicted fatty acid group contents were obtained for 49,127 test-day milk samples from 10,029 first-parity Holstein cows in 810 herds. Milk yield, fat and protein yield, fat and protein percentage, fat-to-protein ratio, and somatic cell score were also available for these test days. Genetic parameters were estimated for the fatty acid groups and production traits using multiple-trait random regression test day models by Bayesian methods via Gibbs sampling. Three separate 8- or 9-trait analyses were performed, including the 5 fatty acid groups with different combinations of the production traits. Posterior standard deviations ranged from <0.001 to 0.01. Average daily genetic correlations were negative and similar to each other for the fatty acid groups with milk yield (?0.62 to ?0.59) and with protein yield (?0.32 to ?0.25). Weak and positive average daily genetic correlations were found between somatic cell score and the fatty acid groups (from 0.25 to 0.36). Stronger genetic correlations with fat yield, fat and protein percentage, and fat-to-protein ratio were found with medium-chain and saturated fatty acid groups compared with those with long-chain and unsaturated fatty acid groups. Genetic correlations were very strong between the fatty acid groups and fat percentage, ranging between 0.88 for unsaturated and 0.99 for saturated fatty acids. Daily genetic correlations from 5 to 305 d in milk with milk, protein yield and percentage, and somatic cell score traits showed similar patterns for all fatty acid groups. The daily genetic correlations with fat yield at the beginning of lactation were decreasing for long-chain and unsaturated fatty acid groups and increasing for short-chain fatty acids. Genetic correlations between fat percentage and fatty acids were increasing at the beginning of lactation for short- and medium-chain and saturated fatty acids, but slightly decreasing for long-chain and unsaturated fatty acid groups. These results can be used in defining fatty acid traits and breeding objectives.     

Volatile Fatty Acids in Some Brands of Whisky, Cognac and Rum

SUMMARY— Gas chromatography was applied to eight different types of whisky, two of cognac, one of brandy, and four of rum to determine the relative proportions of volatile fatty acids; with the lower molecular acids as free acids, but upwards from caprylic acid as methyl esters. Acetic acid and the total amount of volatile acids were measured quantitatively. Rum contained the largest amount of volatile acids, 600 mg/L, while one of the brands of Scotch whisky contained the least, 90 mg/L. Acetic acid represented 40–95% of the total amount of volatile acids in the whisky; for cognac and brandy, the value was .50–75%, and for rum 75–90%. The relative amounts have been reported for 21 acids, with acetic acid excluded. Capric, caprylic and lauric acid were the main components in whisky, cognac and brandy. Of the beverages analyzed, rum contained the largest quantity of lower fatty acids, particularly propionic and butyric acid; the main component of Jamaican rum was propionic acid. The main components of the group of long-chain fatty acids were myristic, palmitic and palmitoleic acids. Scotch whisky contained equal amounts of palmitic and palmitoleic acid; palmitoleic acid regularly appeared in smaller amounts in the other beverages     

卷烟主流烟气总粒相物中挥发性和半挥发性有机酸的分析

采用二氯甲烷萃取、N,O-双(三甲基硅基)三氟乙酰胺硅烷化、反-2-己烯酸和肉桂酸作内标,接预分离柱和选择离子检测GC/MS法同时测定了卷烟主流烟气中的甲酸、乙酸和二十酸等30种有机酸。方法的回收率为74.3%～101.8%,RSD均小于10%。并采用该法测定了10个牌号国产烤烟型卷烟烟气中有机酸含量。该法适于批量卷烟主流烟气总粒相物中挥发性和半挥发性有机酸的快速分析。     

云南、河南烤烟中挥发性、半挥发性游离及结合态脂肪酸的研究

本项研究使用同时蒸馏萃取装置,以及气相色谱仪(GC)和气相色谱/谱联用仪(GC/S),对云南、河南烤烟烟叶中游离态和结合态的挥发性、半挥发性脂肪酸进行了分析。共定量测试了21种酸性成分,并比较了两个烟区烤烟中游离态和结合态的挥发性、半挥发性酸性成分的含量。结果显示,烤烟中分子量较小、挥发性较强的脂肪酸,如异戊酸、戊酸和β甲基戊酸,以结合态形式存在的较多;而分子量较大的半挥发性脂肪酸,游离态形式高于结合态。从云南、河南烤烟比较来看,所测试的21种酸性成分,云南烤烟中游离态与结合态挥发性、半挥发性酸性成分的总量比河南烤烟高。云南烤烟中游离态的挥发性、半挥发性酸性成分总的含量是河南烤烟的1.41倍。特别是一些半挥发性酸性成分(十五碳酸、十六碳酸、十七碳酸和十八碳酸等)在云南烤烟中的含量非常丰富。对结合态的脂肪酸来说,十碳酸及其以下的挥发性酸性成分在河南烤烟中的含量比云南烤烟含量高,明显偏高的是正戊酸和正己酸;而十碳酸以上的半挥发性脂肪酸在云南烤烟中的含量比河南烤烟丰富,比较突出的有正十六酸、油酸、亚油酸和亚麻酸      

浓香、酱香、清香型白酒挥发性风味的特征与差异研究

目的 研究浓酱清3种香型白酒挥发性风味的特征与差异的物质基础。方法 利用气相色谱-离子迁移谱法(gas chromatography-ion mobility spectrometry,GC-IMS)、气相色谱-氢火焰离子检测器(gas chromatography -flame ionization detector,GC-FID)、电子鼻(E-Nose)结合感官评定手段研究了浓酱清3种香型白酒的挥发性风味成分。结果 GC-IMS和GC-FID在3种香型白酒样品中共鉴定出73种挥发性化合物,主要为酯类、醇类、酮类和醛类物质;发现浓香型白酒中的己酸乙酯、己酸含量较高;酱香型白酒物质种类最为丰富,含有多种长链脂肪酸与脂肪酸酯;清香型白酒中物质种类相对较少,乳酸乙酯、乙酸乙酯在其中含量较高;借助偏最小二乘判别分析从39种骨架物质中筛选出16种变量投影重要性(variable important in projection,VIP)值大于1的差异标记物用以区分浓酱清3种香型白酒,分别为甲醇、正己醇、辛酸乙酯、戊酸、乳酸乙酯、丁酸、庚酸乙酯、异戊醇、壬酸乙酯、己酸、己酸乙酯、辛酸、庚酸、戊酸乙酯、甲酸乙酯和乙醛。结论 本研究建立了3种香型白酒的可视化指纹图谱, 以科学的手段阐明浓香型、酱香型、清香型白酒中特征挥发性风味物质与其含量差异。