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摘要绿茶是未经发酵制成的茶，因此较多的保留了鲜叶的天然物质，含有的茶多酚，儿茶素，叶绿素，咖啡碱，氨基酸，文生素等营养成分也较多。本文主要研究绿茶中多酚化合物的提取方法以及多酚化合物的抗氧化性。我们利用溶剂萃取法对绿茶多酚进行萃取，采用正交实验的方法，探索溶剂种类、萃取温度、萃取时间、萃取次数、萃取液浓度等因素对提取率的影响，找到最高提取率的提取条件。同时对提取的茶多酚物质进行检测和抗氧化功能研究。36088
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本实验对市面上的成品绿茶以及与花嫁接的鲜茶进行有机物提取，通过单因素试验和正交试验得知，茶叶的最佳浸提条件为：浸提最佳温度为70℃、浸提最佳时间为30 min、浸提最佳次数为2次、最佳溶剂质量百分数为70%，最佳浸提溶剂为乙醇。通过对茶叶多酚化合物的检测，我们发现，嫁接鲜茶的多酚物质含量在25%至30%之间，相差的并不大。与玉兰花嫁接的鲜茶叶多酚物质含量最多为30.96%其次是兰花为27.04%，桂花最少为26.32%。而市面上出售的茶叶茶多酚物质含量相差较大：碧螺春多酚含量最多为34.03%，西湖龙井次之为28.75%，安吉白茶含量最少为17.15%。
通过多酚抗氧化实验得知：无论是ABTS+自由基清除能力还是DPPH• 清除率或者是Fe3+还原能力，嫁接鲜叶的抗氧化能力都比成品绿茶的抗氧化能力较差。ABTS+自由基清除能力，碧螺春抗氧化能力最强；DPPH• 清除率，与玉兰嫁接的鲜茶叶的抗氧化能力最强；Fe3+还原能力，碧螺春抗氧化能力最强。
毕业论文关键词：绿茶；萃取方法；多酚物质；抗氧化性
The Study on Green Tea polyphenol and its antioxidant function
Abstract This paper mainly studies the extraction method of polyphenol compounds in green tea. We use the extraction solvent extraction of tea polyphenols, orthogonal experiment was used to explore the influencing factors, solvent, extraction temperature, extraction time, extraction times, extraction concentration on extraction efficiency, extraction conditions to find the highest efficiency. At the same time on the extraction of tea polyphenols and antioxidant function of detection.
By single factor test and orthogonal test of extraction of tea can be found: the optimum extraction conditions: extraction temperature of 70 DEGC, extraction time 30min, extraction times of 2 times, the best solvent content was 70%, the extraction solvent was ethanol.Through the study on tea polyphenols extraction and antioxidant function and the experiment we found in the polyphenol content, the grafting between the fresh green tea mainly from 25% to 30%, the difference is not large, single species and content or grafted with characteristic aroma flowers have relations. And Magnolia grafted fresh tea polyphenol content of up to 30.96% followed by 27.04% orchid, osmanthus at least 26.32%. The sale of tea is larger: Spring Snail polyphenol content of up to 34.03%, followed by West Lake Longjing, 28.75%, Anji white tea is the least, 17.15%.
Through the experiment of polyphenol antioxidant that: both ABTS + radical scavenging ability or DPPH clearance or Fe3 + reduction ability and the antioxidant capacity of fresh leaves of grafted than refined green tea antioxidant ability is poor. ABTS + radical scavenging ability, Biluochun the strongest antioxidant activity; DPPH scavenging rate, and Magnolia grafting of fresh tea leaves had the strongest antioxidant capacity; ferric reducing ability, Biluochun tea antioxidant capacity is the strongest..
Key Words：Green tea; polyphenols; extraction; antioxidant activity;
目 录
摘要 I
Abstract II
1 绪论 1
1.1 绿茶及茶多酚简介 1
1.2 茶多酚提取技术研究现状 1