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摘要：茶叶中含有茶多酚、咖啡因、茶多糖、茶蛋白等多种功效成分, 具有降血糖、降血脂、降血压、抗血栓、增强机体免疫力、抗氧化、抗菌和抗辐射等生理功能, 作为保健食品和药品具有广阔的开发前景。本课题主要针对茶叶中的茶多酚和咖啡因的提取工艺进行研究，优化茶叶中的茶多酚和咖啡因的提取条件。采用水提法提取茶叶中的茶多酚和咖啡因，分别用福林酚法和紫外分光光度法来测定其含量。考察了时间、温度、固液比对茶叶的影响，在单因素实验基础上通过正交实验确定了茶多酚和咖啡因的最佳提取条件。实验结果表明：茶多酚的最佳提取条件为温度80℃，料液比为1：30，提取时间0.5h，此条件下提取率为20.76%；咖啡因的最佳提取条件为温度100℃，料液比为1：20，提取时间4min，此条件下提取率为85.35%。24071
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毕业论文关键词：茶多酚；咖啡因；水提取；福林酚法；紫外分光光度法
Research on the different conditions of tea polyphenols and caffeine extracted from tea
Abstract：Tea polyphenols, caffeine, tea polysaccharide and tea protein are the main
bioactive components of it . It has many bioactivities, such as anti-thrombosis, reducing blood-sugar, blood-lipid and pressure depressing , strengthening the body 's immune system, anti-oxidation, antibiosis and radioresistance. And it can be widely used as health foods and medicine. The main subject of study for the extraction process of tea polyphenols and caffeine, optimizing extraction conditions tea polyphenols and caffeine in tea. Using water extraction to extract tea polyphenols and caffeine, its contents were measured by Folin phenol method and UV spectrophotometry. The effects of time, temperature, solid-liquid ratio on tea, on the basis of single factor experiments to determine the optimum extraction conditions polyphenols and caffeine by orthogonal experiment. The experimental results showed that the optimum extraction conditions of tea polyphenols temperature 80 ℃, solid-liquid ratio 1:30, extraction time 0.5 h, this condition extraction rate 20.76%; optimum extraction conditions caffeine is temperature 100 ℃, solid-liquid ratio 1:20, extraction time 4min, this condition extraction rate 85.35%.
Key Words：Tea polyphenols; Caffeine; Water extraction; Folin-Ciocalteu Colorimetry; Ultraviolet Spectrophotometry
目录
1 绪论 1
1.1茶叶概述 1
1.2茶叶国内外研究进展 1
1.3茶多酚概述 2
1.4 茶多酚国内外研究进展 2
1.5 咖啡因概述 3
1.6本课题研究的目的和意义 3
1.7本课题研究的主要内容 4
2 实验材料和方法 5
2.1 实验试剂及仪器 5
2.2 实验方法 6
2.2.1茶多酚标准曲线的绘制 6
2.2.2咖啡因标准曲线的绘制 6
2.2.3 提取茶多酚和咖啡因的单因素实验 7
2.2.4 提取工艺的优化 8
2.2.5微波辅助法对提取的影响 9
2.2.6超声波辅助法对提取的影响 9
2.3分析方法 9
2.3.1福林酚试剂比色法测定（GB/T8313-2008）茶多酚含量 9
2.3.2紫外分光光度法（GB8312一87）测定咖啡碱含量 10
3 实验结果与讨论 11
3.1 茶多酚提取条件的优化 11
3.1.1茶多酚标准曲线 11
3.1.2单因素实验 11
3.1.3正交实验 13
3.2 咖啡因提取条件的优化 14
3.2.1咖啡因标准曲线 14