【作者】 张丽；

【导师】 曾亮；

【作者基本信息】 西南大学 ， 茶学， 2018， 硕士

【摘要】 乌龙茶是六大茶类之一,也是我国的特有茶类,具有天然花果的独特香气和品种的特殊香韵。武夷岩茶作为闽北乌龙的代表,以“岩骨花香”之岩韵深受消费者喜爱;在加工过程中,焙火工艺对形成和发展武夷岩茶特有的色、香、味、形发挥着重要的作用。本文以武夷岩茶中的水仙和肉桂毛茶为样品,分别研究不同焙火程度和不同焙火条件对武夷岩茶品质的影响,采用响应面法对工艺条件进行优化设计,结合气相色谱-质谱联用仪、高效液相色谱、氨基酸自动分析仪、多元统计方法等分析不同焙火处理武夷岩茶的品质成分,旨在找出武夷岩茶的最佳焙火条件,主要研究内容和成果如下:1.不同焙火程度处理的武夷水仙和肉桂,经GC-MS共检测出88种香气成分,包括14种醇类、14种含氮化合物、7种碳氢化合物、19种酯类、18种醛类、12种酮类、1种酸类、2种杂氧化合物和1种含硫化合物。随焙火程度的增加,醇类呈降低趋势,酯类和酮类呈增加趋势。不同品种的武夷岩茶香气成分差异较大,水仙以醇类和含氮化合物为主,肉桂以醇类和醛类为主,且随焙火程度的增加,两个品种的含氮化合物、醛类以及橙花叔醇、芳樟醇、香叶醇等主要香气成分变化趋势差异较大。焙火程度中水仙焙火3(130℃、2 h→130℃、2 h→125℃、2 h→140℃、2 h→145℃、1 h→150℃、1 h)和肉桂焙火2(130℃、2 h→130℃、2 h→125℃、2 h)可以作为武夷岩茶焙火适度的一个参考指标。2.在单因素结果的基础上对武夷肉桂毛茶的焙火条件进行响应面试验设计,对响应面设计下不同焙火条件茶样的主要生化成分进行分析检测,结果发现经焙火处理的肉桂样品的茶多酚、黄酮、可溶性糖含量均低于未焙火的毛茶,而游离氨基酸的变化无规律,应用模糊综合评价法对其焙火后肉桂的主要生化品质进行综合评价,并将模糊综合评价值作为响应面的响应值Y来优化焙火条件,得到的最佳焙火条件:焙火温度为95.06℃、时间为13.92 h、摊叶厚度为8.8 kg/m~2,经过验证试验发现预测值与实际值相差较小。3.不同焙火条件下武夷肉桂的生化成分与茶汤汤色和滋味的相关性分析结果表明,EGC、EC、山萘酚、没食子酸、水杨酸、苹果酸、柠檬酸、抗坏血酸以及茶褐素在一定程度上影响着茶汤色泽。主要儿茶素组分(EGC、EC、ECG)以及大部分氨基酸单体与茶汤滋味得分之间有着显著的正相关关系,没食子酸和茶汤滋味得分之间有着显著的负相关关系,茶汤滋味的通径分析表明,EGC、天冬氨酸、精氨酸对滋味属性以直接作用为主,ECG和亮氨酸对滋味属性以间接作用为主。4.不同焙火条件下的武夷肉桂及其毛茶共检测出128种香气成分,其中醇类11种、含氮化合物16种、碳氢化合物11种、酯类28种、醛类38种、酮类16种、酸类6种、杂氧化合物2种;焙火后武夷肉桂的主要香气组分是含氮化合物和醛类。香气成分的主成分结果显示橙花叔醇、脱氢芳樟醇、β-紫罗酮、正己醛、β-环柠檬醛、苯乙醛、2-庚酮、2-糠酸甲酯、庚醛、α-法呢烯、2-乙基-3-甲基吡嗪、2-乙基-3,5-二甲基吡嗪、芳樟醇、吲哚、苯甲醛、1-乙基-1H-吡咯、α-亚乙基-苯乙醛、苯丙酮等为焙火后武夷肉桂的主要香气成分。5.在主成分分析的基础上,通过构建香气的综合评价模型对不同焙火条件的武夷肉桂样品进行评价,并以香气的综合指数作为武夷肉桂香气品质的评价指标和响应面试验优化焙火条件中的响应值Y,初步预测对武夷肉桂香气品质最佳的焙火条件为:焙火温度为93.71℃、时间为11.92 h、摊叶厚度为6.82 kg/m~2。更多还原

【Abstract】 Oolong tea is one of the six major tea types in China and Wuyi rock-essence tea is also the representative tea of the northern Oolong tea,which is deeply loved by consumers.Baking process is very important for the tea color,aroma,taste and shape of Wuyi rock-essence tea.In this paper,the effects of different baking degrees and different baking conditions on the quality of Wuyi Shuixian tea and Wuyi Rougui tea were studied.Optimizing baking conditions is on the basis of the response surface methodology(RSM)design experiment.Analysis and detection of biochemical components by using gas chromatography-mass spectrometer(GCMS),high performance liquid chromatography(HPLC),amino acid automatic analyzer.The quality changes of Wuyi rock-essence tea in different baking processes were analyzed by means of statistical methods to find out the optimum conditions for the baking of Wuyi rock-essence tea.The main research contents and results are as follows:1.Aiming at exploring the effects of different baking technics on the volatile components and aroma characteristics of Wuyi rock-essence tea,two cultivars of Wuyi rock-essence tea named Shuixian and Rougui were processed with different baking technics.The GC-MS results showed that there were 88 kinds of aroma components detected,including 14 kinds of alcohols,14 nitrogen compounds,7 hydrocarbon compounds,19 esters,18 aldehydes,12 ketones,1 acid,2 heterocyclic oxygen compounds and 1 sulfocompound.As the baking degree increased,the contents of alcohols showed a decreasing trend while the contents of esters and aldehydes showed an increasing trend.Additionally,the aroma components of Wuyi rock-essence tea made from Shuixian and Rougui were significantly different.The aroma components of Shuixian were mainly alcohols and nitrogen compounds while in Rougui,there were mainly alcohols and aldehydes.Moreover,along with the increasing of baking degree,the changing trend of the main aroma components,such as nitrogen compounds,aldehydes,nerolidol,linalool,geraniol,in Shuixian and Rougui were significantly different.According to the sensory evaluation,Shuixian(degree 3,130℃、2 h→130℃、2 h→125℃、2 h→140℃、2 h→145℃、1 h→150℃、1 h)and Rougui(degree2,130℃、2 h→130℃、2 h→125℃、2 h)had the best aroma quality.2.On the basis of single factor results,CCD design was carried out on the baking conditions of Wuyi Rougui tea,and the main biochemical components of tea samples under different baking conditions were tested.The results showed that the biochemical components of Wuyi Rougui tea,tea polyphenol,flavonoids and soluble sugar were lower than those of unbaked tea,while the free amino acids were not changed.The fuzzy comprehensive evaluation method was applied to evaluate the main biochemical quality of the baking process,and the fuzzy comprehensive evaluation result was used as the Y value of the response surface to optimize the baking conditions.The best baking process conditions is:95.06℃,13.92 h,8.8 kg/m~2 leaf thickness.The confirmatory test results show that the difference between the predicted value and the actual value is not significant.3.The correlation analysis results between biochemical components and tea soup color and flavor showed that EGC,EC,kaempferol,gallic acid,salicylic acid,malic acid,citric acid,ascorbic acid and TB affected the color of the tea soup.EGC、EC、ECG and most of the amino acid monomers were positively correlated with the taste score of tea soup,gallic acid were significantly negatively correlated with tea flavor.The path analysis of the taste of tea soup showed that EGC,aspartic acid and arginine have a direct effect on flavor properties,but ECG and leucine have indirect effects on flavor properties.4.Different baking conditions of Wuyi Rougui tea and unbaked tea were detected128 kinds of aroma components detected,including 11 kinds of alcohols,16 kinds of nitrogen compounds,11 kinds of hydrocarbons,28 kinds of esters,38 kinds of aldehydes,16 kinds of ketone,6 kinds of acids,2 kinds of heterocyclic oxygen.Nitrogen compounds and aldehydes are the main aromatic components of Wuyi Rougui tea with baking.The PCA results of aroma show that the main aroma components of Wuyi Rougui tea with baking are nerolidol,dehydrogenation linalool,β-ionone,hexanal,β-cyclocitral,hyacinthin,2-heptanone,methyl-2-furoate,heptanal,α-farnesene,2-ethyl-3-methyl-pyrazin,2-ethyl-3,5-dimethylpyrazine,linalool,indole,benzaldehyde,1-ethyl-1-H-pyrrole,2-phenyl-2-butenal,benzene acetone.5.On the basis of PCA results,the samples of Wuyi Rougui tea were evaluated by the comprehensive evaluation model of aroma.Based on the evaluation index of aroma quality and the Y value of the response surface,the best baking conditions for the aroma quality of Wuyi rock-essence were:93.71℃,11.92 h,6.82 kg/m~2 leaf thickness.更多还原