烟碱转化率与卷烟感官评吸品质和烟气TSNA含量的关系

用具有不同烟碱向降烟碱转化能力的白肋烟鄂烟一号上部叶(2003年)和中部叶(2004年)分别卷制试验卷烟,研究了烟碱转化率与卷烟感官评吸品质和烟丝及烟气中TSNA含量的关系。同一年份的卷烟样品间总生物碱含量无显著差异,烟碱含量和降烟碱含量呈相反趋势变化,从而形成样品间烟碱转化率的梯度差异。感官评吸由5-6名评吸专家组成的评吸小组进行。结果表明,随着烟碱转化率的增高,白肋烟风格程度直线下降,香气质逐渐下降,香气量减少,烟气浓度变淡,生理强度下降,杂气有增加的趋势,余味变劣,口腔残余加重,但刺激性有减小的趋势。两年卷烟样品基本表现相同的趋势,但2003年样品,由于生物碱水平高,不同样品间烟碱转化率的幅度较大,所以各项评吸指标的变化更为明显。随着烟碱转化水平的增高,烟丝和烟气亚硝基降烟碱(NNN)含量和总的烟草特有亚硝胺(TSNA)含量大幅增加,而其它3种烟草特有亚硝胺含量无较大变化。      

用气相色谱/热能分析仪同时测定挥发性亚硝胺和烟草特有亚硝胺

N-亚硝胺很容易在食品、饮料、化妆品、药物、卷烟烟气、各种消费品、甚至在人的胃中形成,已经发现有许多亚硝胺具有致癌性。本项研究开发了一种用气相色谱/热能分析仪同时测定烟草和烟气中的挥发性亚硝胺(VNA)和烟草特有亚硝胺(TSNA)的方法。文章详细介绍了从烟草中萃取亚硝胺的实验条件,讨论了从主流烟气和支流烟气中收集亚硝胺的方法。采用本方法,可在同一张GC/TEA色谱图上分离得到烟草中所有的13种亚硝胺。该方法具有灵敏度和准确度高,重复性好的特点。另外,文中还讨论了添加同位素硝酸盐和烟碱对主流烟气中TSNA含量的影响。此方法也可用于尿液和环境烟气中VNA和TSNA的分析。实验发现吸烟者与非吸烟者尿液中VNA的浓度差异很小,而TSNA的浓度很低,几乎可以忽略。室内空气中的VNA浓度为1~8ng/m,TSNA浓度太低,几乎检测不到。这一结果提示,环境烟气与癌症的关系应当重新考虑。      

三维网状形貌的SBA-15净化新材料

为了拦截卷烟主流烟气中的粒相物并去除烟草特有的亚硝胺TSNA,将具有三维网状结构的介孔材料SBA-15-fib尝试用于去除卷烟烟气中的粒相物和亚硝胺。实验表明,三维网状结构使得SBA-15材料能够有效地拦截卷烟烟气中的粒相物,减少焦油含量,同时将烟草特有亚硝胺TSNA在主流烟气中减少40%以上,其中NNN和NNK被去除得尤为明显。     

国内外主要品牌卷烟主流烟气中烟草特有N-亚硝胺的对比分析

本文采用气相色谱-热能分析仪(GC-TEA)对卷烟主流烟气中主要4种烟草特有N-亚硝胺(TSNAs)进行了分析;优化了前处理过程及仪器分析条件;建立了使用经抗坏血酸处理的玻璃纤维滤片收集卷烟主流烟气,用二氯甲烷萃取卷烟主流烟气中的TSNAs,萃取液经碱性氧化铝层析柱纯化,TSNAs通过GC-TEA定量检测的分析方法;并对国内外较有代表性的98种卷烟样品中的TSNAs进行了系统的分析测定。结果表明,混合型卷烟主流烟气中TSNAs的含量显著高于烤烟型卷烟;国外混合型卷烟中NNK的含量高于国内混合型卷烟。这些研究结果为制定我国卷烟烟气中TSNAs含量限量标准、建立技术壁垒提供了可靠的技术基础。      

国内外主要品牌卷烟主流烟气中气相自由基含量的对比分析

采用电子顺磁共振(EPR)自旋捕集法对国内外196种卷烟主流烟气中气相自由基含量进行了分析测定.结果表明:①卷烟主流烟气中气相自由基含量与焦油及烟碱检测值均无明显相关性,分析认为主要原因可能是卷烟配方中各单料烟的气相自由基含量差异较大;②在同等焦油盒标值下,国内烤烟型卷烟主流烟气中气相自由基平均含量远低于其它卷烟,国内外混合型卷烟主流烟气中气相自由基含量基本相近;③主流烟气中NO和气相自由基含量存在显著的线性相关性(R2=0.891).     

两种抽吸模式对卷烟主流烟气测量方法与结果精密度的影响

为了解吸烟机抽吸模式对卷烟主流烟气相关测量方法与结果精密度的影响,针对卷烟主流烟气的常规指标(抽吸口数、总粒相物、焦油、烟碱、CO)、烟草特有亚硝胺[TSNAs,N-亚硝基降烟碱(NNN)、4-(N-甲基-N-亚硝氨基)-1-(3-吡啶基)-1-丁酮(NNK)]、苯并[a]芘、羰基化合物(甲醛、乙醛、丙烯醛、巴豆醛)、苯酚、氢氰酸、氨、挥发性有机化合物(VOCs,1,3-丁二烯、苯)等17个测试指标,在ISO和加拿大深度抽吸(HCI)两种模式下开展了卷烟主流烟气系列测量方法的协同试验,按照GB/T 6379.2—2004/ISO 5725-2:1994的统计方法进行分析,获得了9个测量方法 6个测试水平(m)下的重复性限(r)和再现性限(R),并确立了r、R与m的线性拟合函数关系。结果表明:焦油、烟碱、CO的测量精密度显著优于其他测试指标,相对重复性限(r%)和相对再现性限(R%)分别约为10%和20%,其他指标的r%和R%分别为20%和45%左右;与ISO抽吸模式相比,HCI抽吸模式下卷烟主流烟气释放量显著增加,但测量方法的精密度对于绝大多数测量指标并没有明显改善;HCI抽吸模式下相关测试指标的精密度对m的依赖性显著较弱,部分指标的两种吸烟机型测试结果差异较大;烟气在HCI抽吸模式下的捕集过程中,吸烟机卷烟抽吸参数(如抽吸口数)稳定性相对较差。因此,当前典型的吸烟机设计并不能较好地满足深度抽吸条件下卷烟主流烟气相关分析物的稳健测量。     

反相二维液相色谱法测定不同烟草制品烟草和烟气中烟碱异构体比值

为研究加热卷烟和传统卷烟烟碱异构体向主流烟气转移的差异性,建立了基于Trap柱捕获-中心切割的反相二维液相色谱法并分离分析传统卷烟和加热卷烟烟草、烟气中S-(-)-烟碱和R-(+)-烟碱异构体。采用所建立的方法研究了加拿大深度抽吸模式下,在加热卷烟和传统卷烟主流烟气中两种烟碱异构体释放量比值(R/S)的差异。结果表明:①传统卷烟烟草中的R/S约在0.16%~0.35%之间,与中心加热卷烟相当,而周向加热卷烟烟草中的R/S明显低于传统卷烟和中心加热卷烟。②传统卷烟主流烟气中的R/S明显高于加热卷烟,而中心加热卷烟主流烟气中的R/S高于周向加热卷烟;烟气中的R/S与加热卷烟和传统卷烟的使用温度有关。      

抽吸方式对卷烟主流烟气烟草特有亚硝胺释放量的影响

为考察抽吸方式对卷烟主流烟气中烟草特有N-亚硝胺(TSNAs)释放量的影响,采用ISO、Massachusetts和Health Canada 3种抽吸方案分别抽吸了15种国产卷烟,而后采用GC/TEA法测定了这些卷烟主流烟气粒相物中的NNN、NAT、NAB、NNK释放量.结果表明:与ISO方案相比,采用Massachusetts方案(50%封闭滤嘴通风孔)或Canada深度抽吸方案(100%封闭滤嘴通风孔),滤嘴打孔卷烟烟气TSNAs总释放量增加100%以上,高通风率卷烟样品的增幅达200%以上;滤嘴不打孔卷烟烟气TSNAs总释放量增加50%左右.     

复合添加剂降低卷烟烟气中多种致癌物研究

为研究降低卷烟烟气中多种致癌物的方法 ,从羊齿类天然植物中提取出多种酮、酚类及其衍生物组合得到复合添加剂 ,以 0 0 0 8%的比例添加于卷烟滤嘴或烟丝中。检测结果表明 ,在卷烟中添加该复合添加剂后 ,其主流烟气中的多种稠环芳烃、自由基和芳香胺等致癌物的含量显著降低 ,对烟气中烟草特有亚硝胺也有一定的清除作用。     

毛细管气相色谱法测定烟草中的亚硝胺

N-亚硝胺是烟草和卷烟烟气中一类重要的具有毒性和致癌性的化学成分。卷烟主流烟气中的N-亚硝胺一半左右直接来源于烟草,而其余则来源于抽吸过程中的热合成作用。我们研究开发了一种配备氮磷检测器的毛细管气相色谱方法来同时测定烟草中挥发性的亚硝胺(VNA)和烟草特有的亚硝胺(TSNA),主要过程包括将烟草样品在柠檬酸磷酸氢二钠缓冲液中超声波萃取,然后将萃取液在硅藻土层析柱上进行固相萃取,浓缩液用DB-5毛细管柱进行气相色谱分析。该方法具有操作简便快速,重复性好,无需专用仪器等特点,适用于各种烟草样品中亚硝胺的分析      

N-nitrosamines in snuff and chewing tobacco on the Swedish market in 1983

Snuff and chewing tobacco on the Swedish market in 1983 were analysed for tobacco-specific and volatile N-nitrosamines using gas chromatography--thermal energy analysis. All 36 samples of snuff analysed were found to contain detectable levels of N'-nitrosonornicotine, N'-nitrosoanatabine, N'-nitrosoanabasine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. Total tobacco-specific N-nitrosamine levels between 2.5 and 51 mg/kg wet weight were found, the mean level being 8.8 mg/kg. Detectable levels of at least two of the four tobacco-specific N-nitrosamines were found in all 18 samples of chewing tobacco analysed. The total concentration of tobacco-specific N-nitrosamines found in chewing tobacco was between 0.1 and 7.8 mg/kg, the mean level being 2.1 mg/kg. The levels of volatile N-nitrosamines found in the 54 samples of snuff and chewing tobacco were very much lower--most of the samples contained less than 10 micrograms/kg and the highest concentration found was 550 micrograms/kg. Since snuff and chewing tobacco contain relatively high levels of carcinogenic N-nitrosamines and there is evidence of an association between the use of these tobacco products and human cancer, snuff and chewing tobacco users should be warned about the possible cancer risk involved in their habit. In addition, efforts should be made to reduce the levels of N-nitrosamines in snuff and chewing tobacco and the formation of these substances in the body from precursors originating from these tobacco products.     

TSNAs的形成、影响因素、分析及清除方法综述

综述了烟草特有亚硝胺(TSNAs)的形成,影响因素(包括硝酸盐和亚硝酸盐、烟草生物碱、温度、湿度和氮肥),分析方法,在烟叶中的分布,致癌性及其清除方法。     

烟碱向降烟碱转化对烟叶麦斯明和TSNA含量的影响

以白肋烟TN90为材料,研究了非转化株、低转化株及高转化株烟叶样品的烟碱转化程度及降烟碱含量与烟叶麦斯明和烟草特有亚硝胺(TSNA)含量的关系。结果表明,随着烟株烟碱转化能力的提高和烟叶降烟碱含量的增加,叶片和主脉的麦斯明含量呈线性增加。当烟碱转化率超过20％时,麦斯明含量超过了假木贼碱的含量。在4种主要的TSNA中,具有不同烟碱转化能力的样品间4-(甲基亚硝胺基)-1-(3-吡啶基)-1-丁酮(NNK)、N-亚硝基新烟草碱(NAT)和N-亚硝基假木贼碱(NAB)含量没有显著差异,N-亚硝基降烟碱(NNN)含量则随着烟碱转化能力的提高和降烟碱含量的增加而大幅度升高,尤其在主脉中表现更为明显。NNN占总TSNA的比例随烟碱转化程度的提高而增加,在高转化烟株中可高达90％,其它3种TSNA占总TSNA的比例相应降低。叶片中NAT含量和比例一般高于NNK,而在主脉中NNK含量高于NAT。     

国外口含型无烟气烟草制品总烟碱、游离烟碱和烟草特有亚硝胺含量分析

采用CORESTA推荐方法测定了65种国外口含型无烟气烟草制品样品的含水率、烟碱、pH、游离烟碱和4种烟草特有亚硝胺(TSNAs).结果表明,口含型无烟气烟草制品的各项化学指标差异显著:含水率为12.07％ ～55.58％;pH为5.55～8.98;以湿重计,烟碱含量为5.41 ～27.68 mg/g,释放游离烟碱含量为0.63 ～ 10.46 mg/g,游离烟碱释放率为7.8％～72.3％;N-亚硝基降烟碱(NNN)为0.31～17.00 μg/g,4-(N-亚硝基甲胺基)-1-(3-吡啶基)-1-丁酮(NNK)为0.07～6.00μg,/g,N-亚硝基新烟草碱(NAT)为0.11 ～6.51 μg/g,N-亚硝基假木贼碱(NAB)为0.01 ～2.54μg/g,同一样品中4种TSNAs总含量为0.54～31.91μg/g.     

微生物亚硝化抑制剂对新型培根品质的影响

将采用商业发酵剂PRO-MIX5(木糖葡萄球菌十清酒乳杆菌十类植物乳杆菌)所制得的菌体碎片(微生物亚硝化抑制剂(microbial nitrosation inhibitor,MNI))应用到新型培根产品中,以降低N-亚硝胺及其前体物质含量.将MNI按原料肉质量比加入腌制液中,并设空白对照组,经腌制、压模、蒸煮、烟熏等...     

烟草特有的N-亚硝胺形成、积累及其影响因素

烟草特有的Ｎ－亚硝胺（ＴＳＮＡ）是一组只在烟草、烟制品及烟气中发现的致癌物质。它们形成的前体物是烟草生物碱、硝酸盐和亚硝酸盐。大田正常生长及成熟的青烟不含ＴＳＮＡ，是采收后在调制、贮存陈化过程中逐步形成和积累起来的。凡影响前体物质的因素，都会影响烟草ＴＳＮＡ的形成、积累和含量。可通过控制两种前体物质的各种途径来降低烟草ＴＳＮＡ。     

氮用量对烤烟叶片TSNA前体物含量及硝酸还原酶活性的影响

通过大田试验,进行了不同氮用量对烤烟叶片TSNA前体物含量及硝酸还原酶活性的影响研究。结果表明,以施纯氮52.5kg/hm2 处理的烟碱、降烟碱、硝酸盐和亚硝酸盐含量适宜,游离烟碱/总烟碱较施纯氮37.5kg/hm2 和82.5kg/hm2处理有所增加,有利于改善烟叶吃味,提高卷烟安全性。      

复合果蔬取代部分硝酸盐对降低发酵香肠中亚硝胺的作用

分析复合果蔬替代硝酸盐对发酵香肠中N-亚硝胺生成的影响,探究发酵香肠生产过程中复合果蔬取代部分硝酸盐的可能性。制备4 组中式发酵香肠：阴性对照组（negative control group,NCG,空白组）、阳性对照组（positive control group,PCG）、芹菜樱桃组（celery and cherry group,CCG）、卷心菜番茄组（cabbage and tomato group,CTG）,考察在发酵及成熟过程中亚硝酸盐、亚硝胺及生物胺含量的变化。结果表明：发酵过程中,果蔬发酵香肠（CCG和CTG）与PCG亚硝酸盐含量同样呈现先增加后降低趋势,但CTG峰值（65.52?mg/kg）显著低于PCG（105.31?mg/kg）。4?组发酵香肠均能检出N-二乙基亚硝胺（N-nitrosodiethylamine,NDEA）,而果蔬发酵香肠（CCG和CTG）在发酵后期NDEA含量（1.23 μg/kg未检出）显著低于PCG（3.72 μg/kg）。干燥成熟阶段,果蔬发酵香肠（CTG和CCG）亚硝酸盐残留量（36.45?mg/kg和47.97?mg/kg）显著高于NCG（24.49?mg/kg）和PCG（31.40 mg/kg）,但在干燥3 d后下降至国家标准限量（30 mg/kg）以下。成品中总生物胺含量排序为NCG＞PCG＞CCG＞CTG,CTG中未检出组胺和酪胺。各组样品中N-二甲基亚硝胺（N-nitrosodimethylamine,NDMA）（PCG除外）和NDEA含量均随干燥进程而逐渐增加,但是果蔬发酵香肠（CCG和CTG）在干燥结束时NDMA（0.16?μg/kg和0.11?μg/kg）和NDEA含量（4.33?μg/kg和4.13?μg/kg）低于NCG（1.73?μg/kg和9.50?μg/kg）,与PCG（0?μg/kg和4.74?μg/kg）相当。实验表明复合果蔬浆替代部分硝酸盐,可降低中式发酵香肠的N-亚硝胺和生物胺含量。     

Simultaneous Determination of Nitrite and Nitrate in Milk Samples by Ion Chromatography Method and Estimation of Dietary Intake

The presence of nitrate and nitrite in foods may be considered hazardous after ingestion in the gastrointestinal tract due to their reaction with naturally occurred secondary amines to form potentially carcinogenic nitrosamines. Due to this fact, a new method was developed in this study for the simultaneous determination of nitrite and nitrate in milk samples using by ion chromatography. Proposed mobile phase composed of sodium hydrogen carbonate and sodium carbonate (1.0 and 3.2 mmol/L) with a flow rate of 0.7 ml/min. The average recoveries for nitrate and nitrite were higher than 86 and 88%, respectively. The limit of detection for nitrate and nitrite were 0.24 and 0.09 mg/L, respectively. The results of 102 real milk samples showed nitrate was found in all of the samples (100%) with a mean of 34 ± 11 mg/L, while nitrite was found in none of the samples. The mean intake of nitrate in all age groups was lower than World Health Organization guideline. The present assessment concludes that the maximum contaminant level was equal to 82.8 mg/L nitrate. This method was fast, sensitive and accurate and is capable of being an alternative method in food control laboratories for investigation of nitrite and nitrate content. This is the first study of the determination and survey of nitrite and nitrate and exposure assessment of the Iranian population to nitrite and nitrate level in milk, which was widely used in infants and adolescents as one of the basic food components.     

Monitoring nitrite and nitrate residues in frankfurters during processing and storage

Frankfurter-type sausages were prepared in a pilot plant with different concentrations of NaNO(2) (75, 125 or 250 ppm) combined or not with 200 ppm KNO(3). A meat system, free of curing agents, was also used as control. Nitrite and nitrate levels were tested in various processing steps and over 120 days storage at 3 °C of the vacuum-packaged frankfurters. Little influence of the originally added nitrite level on the amount of nitrate formed was observed. Important losses of nitrite and nitrate were due to cooking. Thereafter about 50% of the nitrite added initially remained in this form in all samples (39, 59 and 146 ppm, respectively) and between 10 and 15% as nitrate. When only nitrate was initially added, formation of nitrite after cooking was observed (maximum level 43 ppm NaNO(2)). Formulations prepared with both nitrate and nitrite showed no significant differences (p < 0.01) respect to their nitrite or nitrate counterparts. A good correlation among nitrite and nitrate levels and storage time was showed by multiple linear regression analysis. It is concluded that the use of nitrate in combination with nitrite in cooked meat products seems to have little technological significance and adds to the total body burden of nitrite.