【作者】 黄亚辉；

【导师】 陈建华；

【作者基本信息】 中南林业科技大学 ， 林木遗传育种， 2010， 博士

【摘要】 本论文对茶树种质间Y-氨基丁酸(GABA)含量和L-谷氨酸脱羧酶(GAD)活性差异、提高茶叶GABA含量方法、GABA绿茶品质特征以及GABA绿茶改善小鼠抑郁状态和学习记忆障碍作用等方面进行了深入研究。首先研究了30份茶树种质间GABA含量和GAD活性的差异。发现自然条件下,不同茶树种质叶片中GABA平均含量为0.09 mg/g,种质间变异系数为22.61%,GAD活性平均值为1.57u/g,变异系数为51.32%。经3h厌氧处理后,30份茶树种质中GABA平均含量升至1.29 mg/g,种质间变异系数为27.60%,GAD活性平均值升至25.51u/g,变异系数为21.83%。自然条件和厌氧条件下,茶树GABA含量和GAD活性在种质间均存在明显差异。自然条件下茶树种质GAD活性变异系数大,据此进行聚类分析,供试茶树种质可分为三个类群。第1类群茶树GAD活性及GABA含量均较高,为小叶种和中叶种茶树种质；第1I类群茶树以中、大叶种为主；第1II类群茶树中GAD活性及GABA含量均较低,以大叶种为主。以高酶活GAD茶树品种为材料,采用真空充氮和谷氨酸钠溶液浸泡方法均可加工出GABA含量达1.50 mg/g以上的GABA茶。红外线照射和冰醋酸溶液处理均能使茶叶GABA含量提高,但GABA含量未达到1.5mg/g的标准。感官品质方面,真空充氮方法加工GABA茶干茶色泽偏黄或微红,汤色、叶底微黄,香气中夹杂有闷气；液体浸泡方法加工GABA茶干茶色泽、汤色、叶底及香气均正常。真空充氮和液体浸泡处理后茶叶滋味更为醇和,但不及对照样茶的浓爽。生化成分方面,真空充氮方法加工的GABA茶与对照样茶相比,水浸出物含量提高2.5%-6.1%,茶多酚含量降低4.6%-11.6%,游离氨基酸总量提高23.0%-39.1%,咖啡碱和花青素含量与对照接近。液体浸泡方法加工的GABA茶与对照样茶相比,水浸出物含量降低2.5%-3.5%,游离氨基酸总量提高26.9%-54.5%,花青素含量降低12.0%-14.6%,咖啡碱、茶多酚和花青素含量均与对照接近。GABA茶加工过程中GABA与Glu呈现相互消长的关系,茶鲜叶经过连续真空充氮处理后GABA含量大幅上升,Glu含量显著降低。长时间真空充氮处理间以除氮增氧处理可以进一步提高GABA含量。经厌氧处理后茶叶中Pro、GABA、Gly等游离氨基酸含量上升。Glu和Asp含量下降。Thea、Arg、His等游离氨基酸的含量在厌氧条件与正常条件下无明显变化。由厌氧环境转入有氧条件下,GABA、Pro、Thi、Gliu、Asp、Thea等氨基酸含量均有不同程度上升。采用GC-MS方法共分离鉴定出64种香气组分。采用真空充氮方法加工的GABA茶Ⅰ中,顺-茉莉酮、丙酸橙花酯、雪松醇是其特有的香气成份；采用液体浸泡方法加工的GABA茶Ⅱ中,2,6,0-三甲基十五烷、3-甲基十六烷是其特有香气物质。三种样茶中,香气物质总量为GABA茶I>GABA茶Ⅱ>对照样。小鼠悬尾实验和强迫游泳实验结果提示长期给以GABA茶可改善模型动物的抑郁状态。GABA茶抗抑郁作用可能与小鼠脑内GABA浓度上升有关。小鼠跳台实验结果表明高剂量GABA茶对东莨菪碱造成的学习记忆障碍有显著改善作用。GABA茶对小鼠学习记忆障碍的改善作用不是通过降低AChE活性实现的。更多还原

【Abstract】 The differences of the contents of GABA and the activities of GAD among tea germplasms,the methods to increase GABA in tea,the quality characteristics of the GABA tea,the action of the GABA tea to mice depression and learning behaviour obstructed were studied in this research.Under natural condition,the average content of GABA of the tested tea germplasms was 0.09 mg/g,with the variation coefficient of 22.61%, the average activity of GAD was 1.57u/g,with the variation coefficient of 51.32%.After 3h anaerobic treatment, the average content of GABA of the tested tea germplasms increased to 1.29mg/g,with the variation coefficient of 27.60%, the average activity of GAD increased to 25.51u/g,with the variation coefficient of 21.83%.Based on the GAD activity of tea germplasms in natural condition the tested tea germplasms were divided into three groups.In the first group,they were small and medium tea germplasms with high GABA and GAD activity. In the second group,they were mainly medium and large tea germplasms. In the third group,they were mainly large tea germplasms with lower GABA and GAD activity.The GABA content of the tea made by the method of vacuum or immersion was higher than 1.50 mg/g,the standard content of GABA tea, while the GABA content of the tea made by the method of infrared ray or glacial acetic acid was lower than 1.50 mg/g.Treatment of the green tea with vacuum, the characteristics of GABA tea was implicated in the yellowish or reddish dry tea, the yellowish soup and the soaked leaves, the fragrance mixed with other odour, whereas the colour and the fragrance of the GABA tea made by immersion were similar to that of the control green tea, however, the taste of the soup of GABA tea was purer and thinner than that of the control green tea.The contents of the coffein and cyanidin of the GABA tea made by vacuum were close to that of the control green tea. Netherless,compared with the control green tea, the solid content of the water extract increased for 2.5%-6.1%, and the content of the free amino acids increased for 23.0%-39.1%, but the content of the tea polyphenol reduced 4.6%-11.6%. The contents of the coffein, tea polyphenol and cyaniding of the GABA tea made by immersion were close to that of the control green tea, and the content of the water extract reduced 2.5%-3.5%, the content of the cyaniding reduced 12.0%-14.6%, the content of the free amino acids increased 26.9%-54.5%.The relationship of GABA and Glu during the processing of GABA tea was shown as growth and decline. After treatment the green tea with vacuum, the content of GABA grew but that of Glu dropped. The content of GABA was further increased by the treatment that long time vacuum intervened by oxygen. After anaerobic treatment, the contents of Pro, GABA, Glygrew, while that of Glu, Asp dropped, and the contents of Thea, Arg, His changed little. From anaerobic condition to oxygen, the contents of GABA、Pro、Thr、Glu、Asp、Thea grew to varying degrees.The aromatic constituents of the tested tea were analyzed by GC-MS methods,64 aromatic constituents were identified. Cis-Jasmone, Neryl propionate and Cedrol were the characteristic constituents of the GABA teaⅠmade by vacuum treatment, and for the GABA teaⅡmade by immersion, they were Pentadecane,2,6, 0-trimethyl-, 3-Methylhexadecane.For the total amounts of the aromatic constituents, it was: GABA teaⅠ> GABA teaⅡ> control tea.The results of tail suspension and the forced swimming tests in mice,fed with the GABA tea for a long time,demonstrate that the GABA tea possessed significant antidepressant activities which might be attributed to the increasing GABA concentration of mice brain. Furthermore,the evaluation of scopolamine-induced learning and memory deficits of mice via step-down passive avoidance test suggested that the GABA tea could alleviate their symptom, which was not related to the changing of AChE acitivities.更多还原