不同茶树品种、生产季节和加工方法对茶叶挥发性化合物的影响

发布时间：2018-06-10 11:16

本文选题：茶叶香气 + 挥发性化合物　；参考：《浙江大学》2016年博士论文

【摘要】：挥发性化合物是茶叶香气的主要组成成分,是茶叶感官品质的关键成分。茶叶香气种类繁多,受到多种因素的影响,包括茶树品种、农艺技术、茶树生长季节及生态环境条件、茶叶加工技术股和储藏条件等。本文研究了不同茶树品种、生长季节、施肥种类和加工工艺对茶叶挥发性化合物组成和含量水平的影响,为进一步开发提高茶叶香气的技术提供基础数据,获得的主要研究结果如下：1.‘鸠坑种’、 ‘福鼎大白茶’、 ‘金萱’和‘香山早’等4个不同茶树品种的挥发性化合物总含量和挥发性化合物种类组成存在明显差异。4个供试品种挥发性化合物总含量的季节变化趋势有2种不同形式：1) ‘金萱’和‘香山早’2个品种的挥发性化合物总含量表现为：夏季秋季春季；2) ‘鸠坑种’和‘福鼎大白茶’的挥发性化合物总含量表现为：秋季夏季春季。一般春茶的绿茶香气优于夏秋茶,而本研究表明鲜叶的挥发性化合物含量水平是夏、秋茶高于春茶,说明鲜叶的挥发性化合物含量水平与成品绿茶的香气感官品质不存在直接的相关性,可能还受到其他因素的影响,如加工过程鲜叶挥发性化合物在加工过程发生转化、降解或者挥发损失,还有结合态挥发性化合物的释放等。2.鲜叶挥发性化合物种类及其含量水平差异显著,4个供试茶树品种的春、夏、秋3个季节鲜叶中,醇类是最丰富的挥发.性化合物,占总量的50%以上；其次是酯类、醛类和酮类挥发性化合物；酸类挥发性化合物只在个别季节检出,春茶鲜叶没有检出酸类挥发性化合物。在茶树鲜叶中鉴定出28种挥发性化合物,其中3,7-二甲基-1,6-辛二烯-3-醇是含量最高的单种挥发性化合物,占挥发性化合物总含量的10%以上；其次是水杨酸甲酯和3-己烯-1-醇。3.挥发性化合物存在明显的品种地域特征和生长季节特征。2-乙基-1-己醇只在浙江省本地品种‘鸠坑’和‘香山早’中检出,在外省引进的‘福鼎’和‘金萱’2个品种没有检出该物质。香叶醇、顺式氧化芳樟醇和癸酸只在夏、秋茶鲜叶检出,不存在于春茶鲜叶；乙酸正丁酯在春、夏茶鲜叶中检出,但在秋茶鲜叶中没有检出。挥发性化合物组成和含量具有明显的品种特异性和季节特征,说明通过培育品种和改善栽培环境条件可以调节茶叶的挥发性化合物组成和含量,从而达到改善品质的效果。4.施用有机肥对茶叶挥发性化合物总含量的提高是有积极作用的,而且以夏茶作用最明显,秋茶次之,对春茶的影响最小；有机肥对‘舒茶早’和‘碧香早’两个品种的春、夏、秋3季茶叶挥发性化合物总含量水平有积极作用,对‘迎霜’的春茶和秋茶有积极作用,而对‘福鼎大白茶’则只有夏茶有明显效果。说明施用有机肥对茶叶挥发性化合物含量水平的影响受到品种和产地环境的影响,不同品种和生态环境需要不同的施肥技术,才能收到最佳效果。5.绿茶、红茶和乌龙茶加工过程,鲜叶原料的挥发性化合物总含量水平呈现下降趋势。尽管不同品种之间鲜叶原料的挥发性化合物总含量存在明显差异,但加工成同一种茶类后,挥发性化合物总含量水平差异不明显；说明不同茶类品种的香气特征不是取决于挥发性化合物总含量水平,而关键是挥发性化合物的组成。将同一批茶叶分别加工成红茶、绿茶和乌龙茶发现,挥发性化合物总含量水平红茶最高,乌龙茶次之,绿茶最低。说明不同加工工艺对挥发性化合物含量水平的影响不同,红茶的发酵和乌龙茶的摇青可能对挥发性化合物的形成有积极作用。6.在红茶、乌龙茶和绿茶加工过程中,鲜叶原料中的主要挥发性化合物3,7-二甲基-1,6-辛二烯-3-醇(分子量154.25,沸点199-C)和2-己烯醛(分子量98.14,沸点150-C)大量损失,其中绿茶的保留量最少,乌龙茶次之,红茶中这两种物质的含量较高。绿茶和乌龙茶的杀青工序一般是在220℃以上温度作业,可能是造成该两种挥发性化合物损失的关键工序；而红茶加工没有高温杀青过程,干燥作业一般在120℃下进行,所以对这两种挥发性成分的保留量较大。然而,3,7-二甲基-1,5,7-辛三烯-3-醇在绿茶、红茶和乌龙茶加工过程显著升高,差异达到8倍以上,其中乌龙茶含量最高,绿茶和红茶的含量相当；在‘金萱’品种的原料中没有检出2-甲基丁醛,但在红茶、乌龙茶和绿茶产品中都检出该种物质,而且含量水平较高；这些挥发性化合物可能是在加工过程结合态挥发性化合物水解释放出来的。而苯甲醛和2-乙基呋喃含量水平在红茶和乌龙茶加工过程是上升的,但在绿茶加工过程却是降低的。说明不同加工工艺对促进结合态挥发性化合物的水解释放作用存在差异。7.同一批原料加工成不同茶类以后,茶类特异性挥发性化合物差异明显。绿茶的特征性挥发性化合物为吲哚；红茶为2-己烯醛、1-己醇、香叶醇、苯乙醇和水杨酸甲酯；乌龙茶为1-辛烯-3·醇。8.绿茶不同杀青方法对杀青叶和成品绿茶挥发性化合物含量水平的影响不同,般滚筒炒青杀青叶和干茶挥发性化合物总含量高于蒸汽杀青叶及其成品蒸青干茶,其中醇类和酯类挥发性化合物变化规律更明显。滚筒杀青茶及其加工的炒青成品茶的3,7-二甲基-1,6-辛二烯-3-醇、水杨酸甲酯和香叶醇含量明显高于蒸汽杀青叶及其加工的蒸青茶成品。 ‘鸠坑种’和‘福鼎大白茶’两个品种鲜叶加工的蒸青成品茶的吲哚和二甲基丁醛含量明显高于滚筒杀青叶加工的炒青茶。说明不同品种具有不同茶类适制性,选择最适宜的品种才能收到最佳的茶类品质效果。
[Abstract]:Volatile compounds are the main components of tea aroma. It is the key component of the sensory quality of tea. There are many kinds of tea aroma, which are influenced by many factors, including tea tree varieties, agronomic techniques, tea growing season and ecological environment conditions, tea processing technology stocks and storage conditions, etc. This paper studies different tea varieties and grows in this paper. The effects of season, fertilizer type and processing technology on the composition and content of volatile compounds in tea leaves provide basic data for further development of tea aroma technology. The main results are as follows: 1. the volatilization of 4 different tea varieties, such as' Hatoyama ',' Fuding big white tea ',' Jin Xuan 'and' Xiangshan early '. There were obvious differences between the total content of sexual compounds and the composition of volatile compounds. There were 2 different seasonal trends in the total volatile compounds of.4 species: 1) the total volatile compounds of 2 varieties' Jin Xuan 'and' Xiangshan early 'were as follows: Xia Jiqiu Ji Chunji; 2)' Hatoyama 'and' Fuding big ' The total volatile compound content of white tea is as follows: Autumn summer spring. The aroma of green tea in general spring tea is superior to summer and autumn tea. This study shows that the level of volatile compounds in fresh leaves is summer and autumn tea is higher than spring tea, indicating that the level of volatile compounds in fresh leaves does not exist directly with the aroma sensory quality of the processed green tea. It may also be affected by other factors, such as the conversion of volatile compounds in processing, degradation or volatilization loss, and the release of volatile compounds in the.2. fresh leaves of the fresh leaves of the processing process, as well as the difference of the volatile compounds of fresh leaves of the fresh leaves, and the content of the volatile compounds in the fresh leaves of the fresh leaves. 4 fresh leaves of the tea varieties in spring, summer and autumn are the fresh leaves of 3 seasons. The alcohols are the most abundant volatilization. The sex compounds are more than 50% of the total, followed by esters, aldehydes and ketones; acid volatile compounds are detected only in a few seasons, and there are no acid volatile compounds in fresh leaves of spring tea. 28 kinds of volatile compounds are identified in fresh leaves of tea trees, of which 3,7- two methyl -1,6- symplectic. Diene -3- alcohol is the single volatile compound with the highest content of the volatile compounds, accounting for more than 10% of the total volatile compounds, followed by Methylis salicylas and 3- hexene -1- alcohol.3. volatile compounds with distinct regional characteristics and growth season characteristics.2- ethyl -1- hexanol only in Zhejiang Province native varieties' Hatoyama 'and' Xiangshan early ' The 2 varieties of 'Fuding' and 'Jin Xuan' imported from the provinces did not detect the substance. The CIS leaf alcohol, CIS linalool and decanic acid were detected only in summer and the fresh leaves of autumn tea, not in fresh leaves of spring tea; n-butyl acetate was detected in spring and summer leaves, but was not found in fresh leaves of autumn tea. The composition and content of volatile compounds were clear. The variety and seasonal characteristics showed that the composition and content of volatile compounds in tea could be adjusted by cultivating varieties and improving the environment conditions, thus improving the quality of tea. The effect of applying organic fertilizer on the total content of volatile compounds in tea was positive, and the most obvious effect of summer tea, autumn tea, was found in.4.. The second is the smallest effect on spring tea; organic manure has a positive effect on the total volatile compound content of tea in spring, summer and autumn and autumn and 3 seasons in the two varieties of 'Shu tea early' and 'Bi Xiang early', which have positive effects on spring tea and autumn tea 'Ying Frost', but only summer tea in 'Fuding big white tea' has obvious effect. The effects of the level of volatile compounds in leaves were affected by the variety and environment. Different varieties and ecological environment needed different fertilization techniques to get the best effect,.5. green tea, black tea and oolong tea processing process, the total volatile compounds content of fresh leaves showed a decline trend. The total content of volatile compounds in the material was obviously different, but the difference of the total content of the volatile compounds was not obvious after the processing of the same kind of tea. It showed that the aroma characteristics of different tea varieties were not determined by the total content of volatile compounds, but the key was the composition of volatile compounds. Tea, green tea and oolong tea have found that the total content of volatile compounds is the highest, the second of Wulong tea and the lowest green tea. It shows that different processing techniques have different effects on the level of volatile compounds. Black tea fermentation and Wulong tea may have a positive effect on the formation of volatile compounds.6. in black tea, oolong tea and green tea. In the process, the main volatile compounds in fresh leaves are 3,7- two methyl -1,6- ocdiene -3- alcohol (molecular weight 154.25, boiling point 199-C) and 2- hexenal (molecular weight 98.14, boiling point 150-C) loss, of which green tea is the least reserved, uolong tea is the second, and the content of these two substances in black tea is higher. Green tea and oolong tea are generally used in the killing process. The temperature operation above 220 degrees centigrade may be the key process for the loss of the two volatile compounds, while black tea processing has no high temperature killing process and the drying operation is generally under 120 degrees C, so the retention of the two volatile components is larger. However, 3,7- two methyl -1,5,7- octyl three alkyl alcohol is added to green tea, black tea and oolong tea. The difference reached 8 times more than 8 times. The content of Oolong tea was the highest, green tea and black tea were the same. The 2- methyl butyral was not detected in the raw materials of the 'Jin Xuan' variety, but the substance was detected in black tea, oolong tea and green tea products, and the content of these compounds was higher; these volatile compounds may be processed in the process of processing. The concentration of benzaldehyde and 2- ethyl furan in the process of black tea and oolong tea is increased, but the process of green tea processing is reduced. It shows that the different processing techniques have different processes for the hydrolysis and release of volatile compounds in the combination of.7. and the processing of the same batch of raw materials. After different tea classes, the specific volatile compounds of tea types have obvious differences. The characteristic volatile compounds of green tea are indole, black tea is 2- hexenal, 1- hexanol, geraniol, benzol and Methylis salicylas, and uolong tea is 1- octyl -3..8. green tea with different methods for the content of volatile compounds in green and finished green tea The total content of volatile compounds in green leaves and dried tea was higher than that of steam killing leaves and their finished steamed dried tea, in which the changes of the volatile compounds of alcohols and esters were more obvious. The 3,7- two methyl -1,6- octene -3- alcohol, Methylis salicylas and leaf alcohol content in the drum killing green tea and its processed green tea The content of indole and two methyl butyral in the steamed green tea processed by two varieties of 'hatkkeng seed' and 'Fuding big white tea' is obviously higher than that of the roasted green tea processed by the rollers. To the best quality effect of tea.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S571.1;TS272

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