【作者】 周文；

【导师】 朱旗；

【作者基本信息】 湖南农业大学 ， 茶学， 2005， 硕士

【摘要】 速溶绿茶以其有别于传统茶叶的加工方式,丰富的种类和方便、快捷的饮用方式,赢得广大消费者的青睐。但又因其滋味淡薄、香气缺乏等问题制约了市场进一步拓展。为解决发展的“瓶颈”,清楚了解滋味的关键构成成分儿茶素类化合物在速溶绿茶加工过程中的变化趋势及与其共存物质的关系是必要的。本文以儿茶素类的分子结构为立足点,结合工艺参数如温度、浓度等诸多因素,采用HPLC为检测手段,从儿茶素类分子本身及与氨基酸、碳水化合物、咖啡碱等分子之间的相互作用水平上揭示儿茶素类在加工过程中的变化趋势,为速溶绿茶大生产提供实际的指导意义。 本研究系统地比较了工艺Ⅰ、工艺Ⅱ、工艺Ⅲ三种速溶绿茶加工过程中儿茶素类、茶多酚、氨基酸、碳水化合物的变化趋势。研究表明,儿茶素类化合物和茶多酚随着工艺进程都呈现了不断下降趋势,儿茶素类在三种工艺加工过程中减少的比茶多酚均多些,在三种工艺中,儿茶素类和茶多酚的减少:工艺Ⅲ>工艺Ⅱ>工艺Ⅰ;氨基酸和碳水化合物在三种工艺中的变化趋势基本一致,即高—低—高—低。其中氨基酸在工艺Ⅲ的浓缩阶段中的检测值高于原料中的11.19%,碳水化合物在工艺Ⅰ的浓缩环节中的检测值超过了原料中的10.54%。经三种工艺的干燥环节后,速溶绿茶中的氨基酸和碳水化合物基本接近。 电解质、温度、浓度、pn值、时间等因素对儿茶素类化合物的影响试验表明:低温及高温短时对儿茶素类化合物和咖啡碱几乎不产生影响。然而在速溶绿茶复杂溶液中,浓缩温度对其中的儿茶素类化合物表现一种抛物线影响,55℃是儿茶素类化合物变化的分界值,此时儿茶素类总量最高;在冷藏滤液和浓缩液30d的实验中,浓缩液中儿茶素类化合物几乎转化,其中EGC已不能检出,只剩咖啡碱;pH值是对儿茶素类物质影响非常大的因素,当pH>5.16时,随着pH的增大,儿茶素类急剧减少,当2<pH<5.16时,随着PH减小,儿茶素类同样降低,只是降幅减小,当pH<2时,儿茶素类总量减少突然增大;不同浓缩时间对儿茶类影响也较大,随浓缩时间的延长,儿茶素类和咖啡碱均呈不同程度的降低。更多还原

【Abstract】 Instant green tea has been earned the love by the broad masses of tea customers with its many kinds, convenient and fast drinking way and breaking through the tradition manufacture. However, its marketing has been being hampered by some problems, such as lack of aroma, weak taste and so on. The neck of development is settled out smoothly in a while, it is essential that we must make sure of the law of change of the catechins during the process of instant green tea and the relationship between the catechins and coexist compounds. From the perspective of the interaction of amino acid, carbohydrate and caffeine on the catechins and their self-action on the molecular level ,the paper indicated the tendency of regular pattern of the catechins during the process of instant green tea, with it depending on the structure of catechins and applying the means of HPLC of modern instrument. So to seek the deep mechanism could cast light on the theory and practice of manufacture of instant green tea.The paper provids that the tendency of catechins , amino acid , carbohydrate and ployphenol were compared among the three kinds of technics during the process of instant green tea systematically, which were denominated technics II , technics III and technics I respectively. The result obtained above made clearly sense that the catechins and caffeine decreased slowly with the flow of the process, that ployphenol went down a little in comparison with the catechins, and that amino acid suggested the tendency of change was high-low-high-low in accordance with that of carbohydrate, especially in the concentration .So the main biochemical components of instant green tea showed certain regular pattern during the three types s process.Electrolyte, temperature, concentration, time of heating ,pH value etc had different effect on the catechins. It shows that low temperature and high更多还原