不同类型茶叶抗氧化功能的比较研究

发布时间：2018-05-30 16:28

  本文选题：茶叶 + 发酵　； 参考：《湖南农业大学》2012年硕士论文

【摘要】：目前,心脑血管疾病、糖尿病、癌症等己成为危害人类健康的主要疾病,这些疾病病因复杂,但与自由基过量存在引起机体过氧化和脂质代谢异常有一定关系。茶叶已有几千年的饮用历史,相关研究表明茶叶具有有效的抗氧化作用。茶叶根据发酵程度不同主要分为未发酵的绿茶、半发酵的乌龙茶、全发酵的红茶和后发酵的黑茶,不同发酵类型茶叶由于加工过程致发酵机理不同,使不同发酵类型茶叶抗氧化成分及含量均不同。 本文选用4类发酵类型共16种茶叶,采用酒石酸亚铁法测定其茶多酚含量,高效液相色谱(HPLC)法测定儿茶素、茶黄素和没食子酸含量,三氯化铝法测定总黄酮含量,比较不同发酵类型茶叶主要抗氧化成分含量差异,分析不同加工工艺对茶叶抗氧化成分及含量影响；采用ORAC法和DPPH·清除自由基能力法分别测定4类发酵类型茶叶体外抗氧化能力,并与茶叶抗氧化成分进行相关性分析,综合比较不同发酵类型茶叶体外抗氧化能力差异及其与抗氧化成分之间的相关性；建立D-半乳糖衰老模型小鼠,分别灌胃不同发酵类型茶叶于试验末测定小鼠血清、肝脏和脑组组SOD、CAT活力和T-AOC能力,并通过RT-PCR从分子水平检测肝脏SOD和CAT mRNA表达水平,旨在探明不同发酵类型茶叶体内抗氧化能力差异。得到以下主要结果： (1)4类发酵类型茶叶茶多酚和儿茶素含量均为绿茶乌龙茶红茶黑茶,其中绿茶多酚、儿茶素含量(mg/mL)分别为5221+0.707、3520+1025,均显著高于其它3类茶；4类不同发酵类型茶叶茶黄素含量为红茶乌龙茶黑茶绿茶,不同类型茶叶之间比较有显著差异(P0.05)；黑茶、红茶没食子酸含量(mg/mL)分别为0.3244±0.216、0.319+0.067,均显著高于乌龙茶和绿茶(p0.05)；红茶总黄酮含量(mg/mL)为0.160+0.052,显著高于其它3类茶(p0.05)。 (2)茶多酚、儿茶素含量与茶叫ORAC值成正相关并达到显著水平(p0.05)。4类茶叶ORAC值均与其茶黄素含量成正相关,除绿茶外,其余三类茶ORAC值与茶黄素含量的相关性达到极显著水平(p0.01)。4类茶叶清除DPPH自由基能力为绿茶乌龙茶红茶黑茶,与茶多酚和儿茶素含量均成正相关,相关性均达到极显著水平(p0.01)。 (3)信阳毛尖(绿茶)能提高D-半乳糖模型小鼠肝和脑组织指数,差异显著(p0.05)；凤凰单枞(乌龙茶)仅能提高血清CAT活力(5.51±0.66U/mL)和T-AOC能力(14.87±0.57U/mL),差异显著(p.0.05)；信阳毛尖(绿茶)组血清SOD、CAT活力和T-AOC能力(U/mL)分别为139.18±8.19、6.03±0.56和17.67±0.71,均有极显著差异(p0.01),信阳毛尖(绿茶)效果高于川红茶(红茶)和广西六堡(黑茶)；信阳毛尖(绿茶)、川红茶(红茶)和广西六堡(黑茶)对肝脏和脑组织SOD、CAT活力和T-AOC能力均有提高作用,差异显著(p0.05),且信阳毛尖(绿茶)效果强于川红茶(红茶)和广西六堡(黑茶) (4)茶叶能通过上调机体SOD和CAT mRNA表达水平使蛋白合成增多,SOD和CAT活力提高。信阳毛尖(绿茶)组小鼠肝脏SOD基因表达增加,差异极显著(p0.01),CAT基因表达增加,有显著差异(p0.05)。川红茶(红茶)组和广西六堡(黑茶)组小鼠肝脏SOD和CAT基因表达均高于模型组,差异显著(p0.05)；凤凰单枞(乌龙茶)组小鼠肝脏SOD和CAT基因表达均高于模型组,但差异不显著(p0.05)。
[Abstract]:At present, cardiovascular and cerebrovascular diseases, diabetes, cancer and other diseases have become the main diseases which harm human health. These diseases are complicated, but it has a certain relationship with the excessive presence of free radicals and abnormal lipid metabolism. Tea has been drinking history for thousands of years. Related studies have shown that tea has effective antioxidant effects. According to the difference of fermenting degree, it is mainly divided into unfermented green tea, semi fermented oolong tea, full fermented black tea and post fermented black tea. Different fermenting types of tea leaves have different antioxidative components and content in different fermenting types because of the different fermentation mechanism.
The content of tea polyphenols was measured by ferrous tartaric acid by ferrous tartaric acid, and the content of catechin, theaflavin and gallic acid were determined by high performance liquid chromatography (HPLC). The content of total flavonoids was determined by aluminum trichloride. The difference of main antioxidant content in different fermented tea types was compared. Different processing technology was used to analyze tea. The antioxidant capacity of 4 kinds of fermented tea leaves in vitro was measured by ORAC and DPPH free radical scavenging method, and the correlation between the antioxidant components of tea leaves and the antioxidant capacity of different types of tea were compared. The D- galactose aging model mice were fed with different types of fermented tea, respectively, to determine the SOD, CAT activity and T-AOC ability of the mice serum, liver and brain groups at the end of the experiment. The expression level of SOD and CAT mRNA in the liver was detected by RT-PCR at the molecular level. The aim of this study was to identify the differences in antioxidant capacity of different types of fermented tea. Result锛，

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