【作者】 杨亚；

【导师】 傅冬和；

【作者基本信息】 湖南农业大学 ， 茶学， 2020， 硕士

【摘要】 黄茶是中国独有的茶类,也是最小众的茶类,产量占全国茶业生产总量的1%不到。黄茶主要生产原料为春季单芽茶居多,芽叶型原料的黄茶制品较少。夏秋茶叶存在滋味苦涩、香气不高等问题,市场销售困难,利润空间低,造成大量茶园鲜叶利用率极低。茶叶加工工序中闷黄工序能促进酯型儿茶素等苦味物质的降解;摇青工序能有效地促进糖苷类物质水解,降低茶汤的苦涩味,提高香气。本研究选用群体品种为鲜叶原料,比较不同嫩度、不同季节、不同闷黄时间、摇青工序对黄茶茶品质的影响,并对黄茶加工工艺进行优化,以期形成一套黄茶加工的最优工艺及参数。主要研究结果如下:(1)不同嫩度鲜叶加工黄茶品质比较研究的结果显示:同等原料的鲜叶加工成黄茶,可降低茶汤的苦涩感,滋味更加醇和,闷黄后简单儿茶素、氨基酸及单糖双糖类化合物等物质含量保留较多。春秋两季的茶叶品质受嫩度影响较大,原料粗老的春茶和秋茶可用于加工黄茶。(2)做青工艺对黄茶品质的影响研究结果显示:做青工艺对黄茶感官品质影响较大,降低幼嫩茶叶中的品质成分含量,主要是氨基酸类、单糖双糖类化合物,且嫩度越高影响越大,但对于粗老的鲜叶原料,做青工艺可以提升黄茶品质。原料粗老的鲜叶加工黄茶,可采用做青工艺。(3)闷黄对黄茶品质的影响结果显示:在13h的闷黄时间内,闷黄时长对黄茶品质影响不显著,闷黄时长超过13h对黄茶品质不利。闷黄与揉捻的先后对不同嫩度原料的黄茶品质影响不同,原料嫩度较低的鲜叶原料,应先闷黄13h后再揉捻感官品质更好。(4)本研究获得黄茶加工最佳工艺为:芽叶型鲜叶摊放6h左右,杀青后稍摊散失水汽到35℃左右,移到温度50℃、湿度70%的闷黄机中闷黄13h,揉捻至成条,再按传统工艺加工完成。多叶型鲜叶适当摊放后,加入摇青,第一次摇青4min、第二次摇青6 min,转速12r/min,每次摇后静置90-100min,杀青,趁热揉捻至成条,移到温度50℃、湿度70%的闷黄机中闷黄13h,再按传统工艺加工完成。更多还原

【Abstract】 Yellow tea is one of the six traditional Chinese teas and is unique to China.Accounting for less than 1% of the country’s total tea production.The main raw material for yellow tea production is spring single-bud tea,and there are few yellow tea products with bud-leaf raw materials.Summer and autumn tea has problems such as bitter taste and low aroma.Market sales are difficult and profit margins are low,resulting in extremely low utilization of a large number of fresh leaves in tea gardens.In the tea processing process,the sultry process can promote the degradation of ester catechins.The shaking process can effectively promote the hydrolysis of glycosides,reduce the bitterness and astringency of the tea soup,and improve the aroma.In this study,the group varieties were selected as fresh leaf raw materials to compare the effects of different tenderness,different seasons,different yellowing times,and shaking green procedures on the quality of yellow tea,and optimize the yellow tea processing technology in order to form a set of yellow tea processing.It is expected to put forward a set of optimal processing technology and parameters for yellow tea.The main findings are as follows:(1)The results of a comparative study on the quality of processed yellow tea with different tenderness leaves.The fresh leaves of the same raw materials are processed into yellow tea,which can reduce the bitterness of the tea soup and make the taste more mellow.The content of simple catechins,amino acids,monosaccharide and disaccharide compounds and other substances are retained after the suffocation.The quality of tea in spring and autumn is greatly affected by tenderness.Spring and autumn tea with coarse raw materials can be used to process yellow tea.(2)The results of the research on the effect of making green technology on the quality of yellow tea show.The greening process has a greater impact on the sensory quality of yellow tea,reducing the content of quality components in young tea leaves,mainly amino acids,monosaccharides and disaccharide compounds,and the higher the tenderness,the greater the impact,but for the coarse and old fresh leaves Raw materials,green making process can improve the quality of yellow tea.To process yellow tea with coarse and old fresh leaves,the greening process can be used.(3)The results show that the effect of boring yellow on the quality of yellow tea.During the 13 h period of suffocation,the period of suffocation has no significant effect on the quality of yellow tea,and the suffocation period of more than 13 h is unfavorable to the quality of yellow tea.The sequence of sultry yellowing and rolling has different effects on the quality of yellow tea with different tenderness raw materials.Fresh leaf raw materials with lower raw material tenderness should be suffocated for 13 hours before rolling for better sensory quality.(4)The best yellow tea processing technology obtained in this study.The bud-shaped fresh leaves are laid out for 6 hours,and after the greening,they lose moisture to about 35℃.They are moved to a stuffy yellowing machine with a temperature of 50℃ and a humidity of 70% for 13 hours.They are twisted until they become sticks,and then processed according to traditional techniques.After the multi-leaf type fresh leaves are properly spread,add the shake green,the first shake for 4 minutes,the second shake for 6 minutes,the speed is 12r/min,after each shake,let stand for 90-100 min,kill the green,and knead until it is hot.Into strips,move to a suffocating machine with a temperature of 50℃ and a humidity of 70% for 13 hours,and then process it according to the traditional process.更多还原