【作者】 朱旗；

【导师】 施兆鹏；

【作者基本信息】 湖南农业大学 ， 茶学， 2000， 博士

【摘要】 茶作为人们最喜爱的饮料之一，己突破了传统的加工方式，速溶茶以其丰富的种类和方便、快捷的饮用方式，赢得了广大饮茶消费者的喜爱。但因种种原因，迄今为止，速溶茶香气贫乏、滋味淡等问题仍未得到有效的解决，因此速溶茶的消费远不及速溶咖啡普及。 过来速溶茶研究的重点是生产过程中各工艺技术参数与品质形成的关系，多数为国外的发明专利，研究对象多为速溶红茶或绿茶转速溶红茶的加工工艺，对速溶绿茶特别是速溶绿茶加工过程中主要风味物质变化的研究涉及尚少。因此开展这方面的研究，探讨相关研究方法和分析手段，不仅能丰富茶叶深加工的基础理论，填补有关研究的空白；而且对速溶绿茶加工工艺技术参数的改进、提高速溶绿茶的品质提供理论依据。 本研究以生产条件下速溶绿茶在制品为研究对象，采用GC、GC-MS、HPLC等现代仪器分析手段和感官审评方法，研究了速溶绿茶加工过程中香气的变化规律；探讨了不同香气制备方法对速溶绿茶香气研究的差异以及对香气成分的回收率；分析了干燥方法对速溶绿茶香气的影响；比较了顶空过柱和茶汤过柱分析速溶茶香气的差异；跟踪研究了速溶绿茶加工过程中主要生化成分（儿茶素、咖啡碱、氨基酸、游离脂肪酸和可溶性单糖）的变化规律；分析了不同方法制备香气后茶汤的生化成分。研究结果表明： 与绿茶初制过程完全不同，速溶绿茶加工过程是香气总量和组分均逐渐下降的过程，其中提取工艺和浓缩工艺是速溶绿茶香气损失的主要工艺；喷雾干燥后香气总量虽呈下降趋势，但某些香气组分的含量有所增加，有的增加幅度较大；不同香气类型下降的速率有差异，其中碳氢类、酮类、酯类、醛类香气容易损失，而酚类、醇类和酸类香气相对损失较小。在加工过程中，没有检测到新形成的香气物质。 三种不同方法制备的香精油经GC-MS检测，绝大部分香气组分能很好地重复， 但香精油总量和组分数差异明显。SDE法获得的香气总量和组分数最多，其次是顶 空吸附法，减压蒸馏苹取法最少，同时不同类型香气组分的相对含量也有差异。在 回收率的模拟试验中，SDE法对香气组分回收较均衡，回收牢也较高，顶空吸附法 对葵酸乙酯的回收串几乎为100＄，而减压蒸馏苹取法对酯类物质的回收率较低。跟 0 踪分析速谊绿茶加工过程中香气的变化，发现制备方法不同，香气变化的趋势也存 在一定差异。用SDE＄分析，香气在浓缩工艺下降趋缓，其余两种方法至干燥时香 气下降才趋缀。另外，不同方法制各香精油后的茶汤经生化分析和感官审评也存在 较大差异，特别是以速溶绿茶制备香气后的茶汤差异更明显，这进一步说明不同香 气制备方法对茶样的影咱不同。因此，采用何种方法制备香气不能只以香气总量和 组分敛为准，而应以制备的香气能尽可能地反映茶叶香气的风味特征。比较上述三 种香气制备方法，虽然减压蒸们苹取法还存在一些不足，但总体上该方法制备的香 精油能较好地反映奈叶香气的凤味特征，特别是对速溶绿茶香气的分析较适合。 干燥方法不同对香气物质的彤咱差异明显，喷雾干燥速溶绿茶的香气损失较 大，荣者Z味低淡。冷冻干燥能较好地保存速溶绿茶的香气，但在冷冻于燥过程中 也存在香“旬质的损失。 顶空吸附与茶汤过柱吸附虽然吸附剂相同，但经过吸附剂的物质差异较大，所 制备的香精袖组分差异较大，而且过柱吸附法分离出一些别的物质。 速溶绿茶加工过程中咖啡碱和儿茶素总量逐渐增加，与感官审评的结果较一 致，但儿茶素组分间存在一定差异．可溶性单糖和游离氮基酸呈高一低一高一低的 变化，特别是浓缩和干燥工艺有较大幅度的起伏，虽然对产生这种现象的原因作了 一些分析，但变化机理仍有待进一步研究。游离脂肪酸在速溶绿茶中的含量十分低， 仅为原料的0．5＄左右，可能不是风味的主要成分。 香葡油制备过程中，采用低温冷冻脱水，时间短、效果好。玻璃毛细管能有效 地保存浓缩后的茶叶香气。采用卜甲基昧哩对单糟进行衍生能较好地分析茶叶中可 溶性单糖，该方法操作方便、分离效果好。AccQ．T％法能较好地分析茶叶氨基酸。 捉高速溶绿茶香气的措施：适当捉高绿茶原料的品质；在速洛绿茶加工前和过 程中回收香气，微胶囊化后返回到速绿溶茶中；探讨提取工艺新的工艺参戮；采用‘ 膜浓缩或冷冻浓缩技术；中档速溶绿茶可适当添加天然香精油，高档速溶绿茶宜采 用冷冻干燥。更多还原

【Abstract】 As one of the beverages people like best, tea has broken through the traditional manufacture. Instant tea has been won the love by the broad masses of tea customers with its many kinds, easy and fast drinking way. However instant tea has not been as popular as instant coffee so far because some problems, such as lacking aroma, weak taste and so on, have not been solved efficiently. In the past the key point of researches on instant tea was the relationship between the technical indices and the quality during the process, most of them were the foreign invent patents. The objects of study were almost instant black tea or the manufacture way of involving green tea into instant black tea. There is little reports on instant green tea, especially the change of flavor of instant green tea during the process. So to start the study on this field, to seek the means of research and the way of analysis could be not only to enrich the basic theory of tea further manufacture, to fill in the gaps in the field of instant tea, but also to provide the basis for increasing the quality of instant green tea by improving the technical indices during the process of manufacture. It researched the objects of instant green tea during the process in KingLong instant tea factory. With the means of GC, GC-GM, HPLC of modern instruments and the way of tea taste it studied on the aroma change of instant green tea during the process, the difference of essential oil made by SDE method, Headspace absorb (HSA) method, Vacuum Distillation Extract (VDE) method, the rate of aroma recovery of different aroma methods, compared the aroma diversity of instant tea of Headspace absorb (HSA) method with that of Tea Liquid absorb (TLA) method, analyzed the change of main biochemical components of instant green tea during the process and the main biochemical components of tea liquids after making essential oil by different aroma methods. The results showed that the aroma components of essential oil got by three aroma methods could be repeated greatly by GC or GC-MS analysis, but the content and the numbers of components were remarkable difference. SDE method gained the highest content and the numbers of components of aroma, the next was HSA method, and VDE method got the lowest. Meanwhile the relative content of different groups was different. In the simulated test of the rate of aroma recovery, SDE method could recovered aroma in harmony and had higher rate of aroma recovery. HAS method almost recovered all the standard decanoic acid ethyl ester. VDE method had very low rate of esters recovery. It showed that there was certain different tendency of aroma decreasing in different aroma methods during the process of instant green tea. The aroma went down slowly in the concentration analyzed by SDE method, and the other tow methods decreased slowly in the spray dry. In addition, the tea liquid after making essential oil by different aroma methods was different in biochemical components and in tea taste, especially the liquid of instant green tea after making essential oil. It further explained that there was diversity between aroma methods. So to select an aroma method could not be depended on the content and the numbers of aroma got by it, and should be depended on the aroma which could reflect the characteristic of tea flavor. Although there were some problems exited in the VDE method, it was better to reflect the flavor of tea aroma, especially for the aroma analysis of instant green tea. Different dry process更多还原