【作者】 潘科；

【导师】 杨坚；

【作者基本信息】 西南大学 ， 茶学， 2009， 硕士

【摘要】 多环芳烃(Polycyclic aromatic hydrocarbons,简称PAHs)是指分子中含有两个或两个以上苯环的碳氢化合物,可分为芳香稠环型及芳香非稠环型。PAHs数量大,分布广,对人类危害大,其中多种多环芳烃已被鉴定出具有致癌性。茶叶中PAHs的主要来源于茶叶的加工过程及茶鲜叶对环境中PAHs的吸附和吸收。本论文以川渝地区带有烟味(煤、柴)和由加工原因造成带焦糊味的茶叶为研究对象,借鉴现有相关研究成果,运用现代化学分析方法,对茶叶中的PAHs进行了分析,对茶叶中PAHs在不同影响因素下的浸出率及浸出规律进行了研究,并通过研究结果对茶叶中PAHs对人体潜在的危害性进行了评价。首先,对PAHs的提取及检测方法进行了研究,确定了实验方法。16种PAHs标准样品的检测中,色谱图显示PAHs分离效果好,出峰较尖锐,具有较好的选择性;干茶中PAHs的提取,PAHs的加标回收率为72.3%～105.7%之间,4次重复实验的标准偏差在5.08%～19.7%范围内,均低于20%;茶汤中的PAHs提取,低环PAHs的加标回收率较低,萘为25.5%,3环PAHs为50.1%～58.9%,4～6环为80.0%～88.9%,可能是由于PAHs在冲泡过程中会挥发造成的,4次重复相对标准偏差低于19%。结果表明,本研究实验方法比较准确。其次,对干茶中PAHs的含量进行了定量分析并通过PAH毒性相当因子转化分析了各茶样的潜在毒性。横向和纵向比较了不同地区、不同烟味茶样中PAHs的组成及含量的差异,结果表明不同地区茶样中PAHs的组成和含量差异明显,不同地区不同茶样中PAHs组成和含量差异明显,同一地区不同茶样中PAHs组成和含量差异明显。但均表现出二氢苊浓度最高的特点。说明茶叶中PAHs的含量及组成存在明显的地区差异性和显著的共性。第三,对茶叶中PAHs在茶汤中的浸出率进行了详细的研究。为了便于试验结果的比较,本文选择了同一地区不同烟味的茶叶(筠连煤烟、柴烟茶)为研究对象。首先参照大众的泡茶习惯设定了3个泡茶因素,即冲泡时间、冲泡温度、冲泡次数,并分别设置了5个水平,分析了两个茶样在单个影响因素下,PAHs在茶汤中浓度、浸出率及浸出规律,其次在单因素试验结果的基础上设计了3因素3水平的正交试验,探讨在多因素复合影响下PAHs在茶汤中浓度、浸出率及浸出规律。试验结果表明,试验设计的3个因素对PAHs在茶汤中的浸出率都有影响。其中影响煤烟茶和柴烟茶中PAHs浸出率的最主要因素都是冲泡时间的长短;检测出的PAHs都集中在环数较少的PAH,5环的PAHs仅在较少的试验水平中检出,无6环的PAHs检出,无论煤烟还是柴烟茶中PAHs的浓度都以二氢苊的最高;在冲泡次数影响下,煤烟茶、柴烟茶中PAHs的总浓度和总浸出率,比在冲泡时间和温度影响下要低。随着冲泡次数的增加,浸泡到茶汤中的PAHs的总量会增加,柴烟茶比煤烟茶的结果更明显;煤烟茶、柴烟茶中PAHs的总浸出率在单因素试验中都表现出一定的规律,柴烟茶受因素影响的作用较煤烟茶明显;正交试验中,柴烟茶中PAHs的总浸出率普遍比煤烟茶高。PAHs在茶汤中的浸出率受冲泡因素的影响是非常明显的。更多还原

【Abstract】 Polycyclic aromatic hydrocarbons(PAHs) are hydrocarbons with two or more benzenes in a molecule and divided aromatic hydrocarbons and non-aromatic hydrocarbons.PAHs have a large amount and distribute widely,crime against humanity,in which a variety of polycyclic aromatic hydrocarbons have been identified with carcinogenic.PAHs in the tea are main from processing of tea and adsorption or absorption from the environment.This paper took the tea in Sichuan～Chongqing region which had a strong smell of smoke(coal,firewood) and is caused by the processing of tea with singe for the study,used existing research results for references, used the knowledge of modern analytical chemistry and equipment,analysed the PAHs in the tea leaves,studied the the rate of PAHs and soaking law in tea soup at different affecting factors,then used the results to evaluate potential harm to the human body of the PAHs in the tea.1.This paper studied on the extraction and detecting method of PAHs and detected the standard sample.In each of 16 PAHs divided,the peak of PAH is shrilly,and the selectivity of PAHs is preferably.The extraction of PAHs in dry tea,the rate of PAHs recovery is from 72.3%to 105.7%,and the standard deviation of four experiments is from 5.08%to 19.7%.The extraction of PAHs from tea soup,the rate of PAHs recovery is low,NA is 25.5%,three rings PAHs is from 50.1%to 58.9%, four to six rings PAHs is from 80.0%to 88.9%,standard deviation of four experiments is underby 19%.The reuslts indicate that the extraction and detecting method of PAHs is relatively accurate.2.This paper quantitatively analyzed the PAHs in the dry tea,then through the toxic PAH factor analyzed potential toxicity of every tea.This paper horizontal and vertical compared the PAHs in the composition and content differences from different regions and different kind of smoke tea,and the results show that the PAHs in the teaes from different parts composition and content are obviously different.In different parts, different kinds of smoke in the composition and content of PAHs are obviously different.In the same area,different kind of smoke tea in the composition and content of PAHs are obviously different.But all show the highest concentration of PAHs is Acenaphthene which shows that there is an obvious regional differences and commonness of constitutes and content of PAHs in tea.3.Study on the rate soaking of the PAHs in tea in detail.In order to facilitate comparison of test results,the paper chose the same area different smokeing tea (Junlian soot,firewood tea) for the study.First of all,based on the popular drinking method of tea to set 3 effecting factors,that is,the dip time,the dip temperature,the dip number,and were set up 5 level,then analysing the PAHs in the two tea samples effects of a single factor,In the tea in concentration,the rate of leaching and extraction rules,This was followed by a single factor test results on the basis of the design of the 3.This paper studied on the rate soaking of the PAHs in tea in detail.In order to facilitate comparison of test results,the paper chose the same area different smokeing tea(Junlian soot,firewood tea) for the study.First of all,this paper based on the popular drinking method of tea to set 3 effecting factors,that are,the dip time,the dip temperature,the dip number,and to set up 5 levels,then analyzed the PAHs of two tea samples in a single factor,in the tea in concentration,the rate of leaching and extraction rules.This was followed by single factor test results on the basis of the design of the 3 factors that the level of 3 orthogonal to explore in more complex factors under the influence of the concentration of PAHs in the tea,the rate of leaching and leaching law.Test results show that the experimental design of the 3 factors for the PAHs in the tea extract rate will be affected.The loss of the diesel soot and smoke Cha Cha PAHs in the leaching rate of the most important factor is the length of brewing time;PAHs were detected in the loop on the small number of PAHs,5 of the ring PAHs were only in the low level of test,and the experiment detected no PAHs, detected no 6 of the ring,regardless of diesel smoke or soot Cha Cha,the concentration of PAHs has the highest concentration of dihydrogen Acenaphthene;On the influence of the number of brewing tea,the total concentration and the leaching rate of PAHs in the soot and smoke Chai tea are lower than on the influence of the brewing time and temperature.With the increase in the number of leaves,soak in the tea will increase the total amount of PAHs,Chai tea has an more obvious result than smoke soot;the total PAHs of Tea soot,smoke Chai tea in the leaching rate of single～factor tests have shown a certain degree of regularity,the effect of Chai Tea on the influence of factors are more obvious than soot tea;Orthogonal,the rate of extraction of PAHs in Chai tea is higher than in soot tea.PAHs in the extraction rate of tea brewing by the impact is very obvious.更多还原