青砖茶渥堆中特征风味形成机理及品质调控技术研究

Qingzhuan brick tea is a major member of dark tea,which is mainly produced in southern region of Hubei Province and northern region of Hunan Province.It is a daily necessity of minority people living in Inner Mongolia, Xinjiang,Gansu,etc.However,the mechanism of its characteristic quality and flavor formation has hardly been studied,which seriously restricts the development of Qingzhuan brick tea industry.Based on the research foundation of dark tea in Hunan Province, the material foundation of characteristic flavor of Qingzhuan brick tea in Hubei Province will be further researched using UPLC-MS-MS,GC-MS-MS and ICP-MS in this project. By advanced PCR-DGGE and MLST methods, we will also isolate and identify variation trend of community structure and diversity of microorganism during pile-fermentation of Qingzhuan brick tea. Futhermore,the change rule of enzymes coming from tea and microorganism will be investigated during pile-fermentation of Qingzhuan brick tea by modern enzymology technology. Dynamic change rule of catechins,amino acids,alkaloids,organic acids,saccharides,flavones and volatile components will be fully tested with the most advanced qualitative and quantitative analysis methods.Through all these above research work,the interactive growth and decline rule will be revealed among microorganism, enzymes and quality components and the biochemical mechanism of characteristic quality and flavor formation of Qingzhuan brick tea during pile-fermentation will be clarified. And then processing technology of qingzhuan tea will be innovated to shorten production cycle as well as regulate and optimize its quality.

青砖茶是黑茶类的主要成员之一，主产于鄂南和湘北地区，是我国内蒙古、新疆、甘肃等地区少数民族日不可缺的生活必备品。然而，茶学界对青砖茶特征品质风味形成机理的研究几乎处于空白，严重阻碍着青砖茶产业发展。申请人及项目组基于对湖南黑茶的研究基础,以湖北青砖茶作为研究对象,采用UPLC-MS-MS、GC-MS-MS、ICP-MS等分析手段，深入研究青砖茶特征风味的物质组成基础,采用PCR-DGGE、MLST等先进方法分离鉴定渥堆中微生物菌群结构变化趋势和多样性，采用现代酶学技术分析渥堆中茶源酶和微生物酶类的变化规律，以最先进的定性定量分析手段全面检测渥堆中儿茶素、氨基酸、生物碱、有机酸、糖类、黄酮类、挥发性成分等的动态变化规律，揭示渥堆中微生物、酶类及主要品质成分在青砖茶渥堆中的互动消长规律，探明青砖茶渥堆中特征品质风味形成的生化机理，进而创新加工工艺，缩短生产周期，调控优化青砖茶品质。

青砖茶作为黑茶类的主要成员之一，由鲜叶经过杀青、揉捻、渥堆、干燥等工序加工而成，主产于鄂南和湘北地区，是我国内蒙古、新疆、甘肃等地区少数民族日不可缺的生活必备品。近年来，随着人们保健意识不断提高和包括湖北青砖茶在内的黑茶保健功效不断阐释，青砖茶消费区域和消费群体得到了不断拓展。然而，青砖茶特征品质风味物质基础、渥堆中品质成分、微生物及产酶、以及其品质提升与高值化利用等方面的应用基础研究几乎处于空白，严重阻碍着青砖茶产业发展。本项目主要研究内容及主要结论如下：(1)青砖茶特征风味的物质基础研究：不同来源或年份青砖茶中品质组分（香气组分、儿茶素组分、茶黄素组分、生物碱组分、氨基酸组分、有机酸组分、矿质元素组分)的含量存在相当的差异性，因而须强化青砖茶加工原料与工艺、产品质量标准。另外，建立了青砖茶HPLC指纹图谱的方法。(2)青砖茶渥堆中品质成分研究：随着渥堆的进程，茶坯含水量、水浸出物、茶多酚、水溶性糖、游离氨基酸、水溶性蛋白质、儿茶素、黄酮、纤维素、色差值、香气、单糖和有机酸等均表现出显著性变化，而pH值和灰分变化差异较小。(3)青砖茶渥堆中微生物研究：获得9株真菌，其中2株枝孢属，5株曲霉属和2株青霉属；获得18株细菌，其中4株短杆菌属，12株芽孢杆菌属，1株葡萄球菌属和1株纤维单胞菌属；筛选获得明显产纤维素酶和蛋白酶的真菌2株，明显产多酚氧化酶的真菌1株；DGGE 技术分析表明青砖茶渥堆过程中以曲霉菌属为主，其次为酵母菌和踝节菌属。(4)青砖茶品质提升及高值化利用的相关研究：优化得到青砖茶茶多酚提取工艺参数；青砖茶提取物不同极性部位有抑菌和抗氧化作用，以乙酸乙酯层尤为突出；青砖茶粗茶多糖(CTPS)及级分CTPS-1和CTPS-2的抗氧化活性均存在剂量依赖关系且与各自结构特性有关及探索得到青砖茶部分品质成分溶出动态等。本项目研究结果为进一步研究青砖茶特征品质风味形成机理，促进青砖茶产业发展，引导青砖茶饮用提供了的重要基础与支撑。