Analysis On The Difference Of Antioxidant Activity Of Traditional Tea And Newly Trial-produced Tea In Henan Province

Lu Yu wrote the book named “The Classics on Tea” in which the tea from Guangzhou area was the best Huainan tea.Ancient Guangzhou belongs to the present Huangchuan region in Xinyang city.Xinyang is nowdays the main tea-producing area in Henan Province.Although the tea here has a long history,at present,the tea category is relatively single and the utilization rate of fresh tea leaves is low.In order to make people much more understand the quality of Yu tea,such as antioxidant activity of the tea.Finally,that would increases the added value of the tea.In this paper,traditional tea and newly developed tea in Henan were selected,including two different grades of Xinyang maojian green tea,two different grades of Xinyang black tea and three kinds of new tea.Xinyang maojian is the main green tea produced in Henan tea district and one of the top ten most famous teas in China.Xinyang black tea was a kind of new black tea made from relatively delicate fresh leaves in 2010.Qiyan,Qibai and Qihong were new teas produced in recent years.The processing of Qiyan tea was carried out according to the production technology of Wuyi yan tea which was Oolong tea in Northern Fujian.Qibai was white tea and Qihong was black tea.The fresh leaves of these three kinds of tea mainly came from local tea groups.In this paper,firstly the main components in these teas were detected by high performance liquid chromatography(HPLC)and spectrophotometer,including eight catechin monomers,tea polyphenols,flavonoids,gallic acid,caffeine,amino acids and tea pigment and so on;Then DPPH and FARP methods were used to detect the antioxidant strength of seven kinds of tea in vitro.Secondly,the antioxidant activity of seven kinds of tea was detected by the diabetic mouse model.Finally,the sensory evaluation of these teas was carried out,and the mathematical statistical analysis method was used for comprehensive analysis.The main results were as follows:1.Tea quality characteristics: Xinyang maojian was a kind of traditional famous green tea,due to different picking standards and different production periods,the sensory quality of tea varied greatly.It was generally believed that the more tender the fresh leaves were,the better the quality of the dried tea and the better the sensory quality.There were three kinds of black tea including Xinyang black tea 1,Xinyang black tea 2 and Qihong black tea.Due to different picking time,different tea varieties and different processing technology,it was generally considered that the content of theaflavins in tea was higher,the content of theabrownines was less,the soup color of the black tea was red and bright,and the tea quality was better.Qiyan olong tea and Qibai white tea had their own unique quality characteristics due to different picking standards and different production processes.These seven kinds of tea cover four types of tea.2.In vitro antioxidant activity: By performing DPPH and FRAP antioxidant tests on the seven tea extracts,it was found that the strength of the antioxidant activity assay detected by two methods was basically the same.Calculating the IC50 values for the strength of scavenging DPPH radicals,the 1/IC50 values of the seven kinds of tea were in the order of magnitude of Xinyang maojian green tea>olong tea>white tea>black tea(P<0.05).The order of FRAP values for the seven kinds of tea was XY2>XY1>QY>QB>QH,XH1 and XH2,with significant differences(P<0.05).Correlation analysis showed that tea polyphenols,vitamin C,total catechins,EC,EGC,EGCG,ECG,GCG,C and GC were negatively correlated with IC50 values and the difference was highly significant(P<0.01);the IC50 values were positively correlated with flavonoids and gallic acid and the difference was highly significant(P<0.01).FRAP values were positively correlated with polyphenols,vitamin C,total catechins,EC,EGC,EGCG,ECG and C,and the difference was highly significant(P<0.01);negatively correlated with flavonoids and gallic acid,and the difference was highly significant(P<0.01).3.In vivo antioxidant activity in diabetic mice: it was found that the diabetic mices treated with XY2 lost the weight of 9.25 g after 14 days,while the group treated with QH gained 0.41 g,the blank(KB)group gained 3.04 g and the control(DZ)group gained 0.47 g.The results of MDA in the liver tissue of the diabetic mices treated with different treatments: the group treated with XY2 had the lowest MDA content and the difference was significant(P<0.05),while the the group treated with XH2 did the highest MDA content(P<0.05).Among the 10 treatments,glutathione transaminase(GOT)was the highest in the DZ group and differed significantly(P<0.05)from the KB,XY1,XY2,and QY treatment groups;the smallest GOT value in the XY2 treatment from the other treatments(P<0.05).Glutathione alanine transaminase(GPT)values in the XY2 treatment were the lowest and differed significantly(P<0.05)from the other treatments and XH2 treatment had the highest GPT value and was significantly different from XY1 treatment and XH1 treatment(P<0.05).The content of glutathione peroxidase(GSH-Px)was greater in XY2 treatment,QY treatment and QH treatment than DZ,with QY treatment and QH treatment differing significantly from them(P<0.05);XH2 treatment had the lowest content of GSH-Px and differed significantly from XY1,XY2 and QY group treatments(P<0.05).QY treatment had the highest content of GSH-Px(P<0.05).DZ treatment had the lowest SOD content among all treatments,and the XY1,XY2,XH2 and QB treatments had greater SOD content than the control treatment,with significant differences(P<0.05).In conclusion,this paper have investigated the differences in antioxidant activity between different grades of tea and different types of tea,and there is a certain consistency between in vitro and in vivo assays,which provides scientific guidance for people to drink tea rationally,provides a theoretical basis for new tea development,and lays the foundation for in-depth investigation of antioxidant mechanisms.