Main Components Analysis And Activity Evaluation Of Partridge Tea With Different Fermentation Degree

Partridge tea,also known as mountain bitter tea,gramineous tea,hairy tea,is a species of Euphorbiaceae,wild tree,is a relatively rare wild tea tree in China,but also a rare large leaf tea varieties in China.Partridge tea has a rich flavor,with clearing heat and detoxification,anti-inflammatory diuretic,greasy appetizer,analgesic and other effects.There are few studies on the effect of fermentation on the quality of partridge tea,In this study,partridge tea produced locally in Hainan was studied,the effects of fermentation on sensory quality,nutritional quality,functional quality and microbial flora content and species of partridge tea were compared and analyzed in order to provide scientific basis for the development and utilization of partridge tea products.The specific studies are as follows:1.The effect of fermentation on sensory quality of partridge Tea,the results showed that :(1)After fermentation,the shape,color and flavor of partridge tea changed greatly,whether it was tea powder or tea soup.In color,Brightness and yellowing are greatly reduced,and red and blue change increase.After fermentation,the browning index(BI)increased from 0.17 to 0.54,it can be seen that fermentation causes the browning degree of tea to become greater,the color deepened.(2)By HS-SPME-GC/MS,76 and 73 volatile components were identified from partridge tea green tea and black tea respectively.Terpenes were the main aroma components in both partridge tea,accounting for 32.9% and 30.1% of the total components,followed by aldehydes.It accounted for 19.7% and 16.4% of the total components,respectively.The species and contents of terpenes and aldehydes in partridge tea decreased after fermentation.2.The effects of fermentation on the main nutrients of Partridge tea,The results showed that :(1)16 kinds of amino acids were detected in partridge tea green tea and partridge tea black tea.The highest amino acids in both kinds of tea were glutamate and aspartic acid.After fermentation,the contents of protein and amino acids in partridge tea decreased.(2)EAA/TAA ratio of partridge tea green tea and black tea was 0.548 and 0.546,respectively.SRC values were 48.4 and 52.9,respectively,and methionine was the first limiting amino acid,indicating that fermentation could lead to a slight increase in the nutritional value of partridge tea.(3)The contents of fresh amino acids(Glu+Asp)and sweet amino acids(Ala+Gly+Ser+Pro)in partridge tea after fermentation decreased by 7%,and the contents of aromatic amino acids(Tyr+Phe)decreased by 12% after fermentation.(4)Fermentation leads to a significant reduction in the composition of reducing sugar and reducing sugar in partridge tea.3.The evaluation results of fermentation on polyphenol composition and antioxidant activity of partridge tea showed:(1)By LC-MS/MS method,36 kinds of active substances were found in partridge tea green tea and black tea,but the types of active substances were different.The highest content was rutin,followed by chlorogenic acid,quinic acid,guava glycoside and so on.The whole content of polyphenols in partridge black tea decreased,especially rutin,chlorogenic acid,guava glycoside and phenylalanine,which decreased by 15.5%,7.9%,33.1% and 31.6%,respectively.After the fermentation of partridge tea,the contents of phenyl alcohol-3-O-genoside,vitexin and ferulic acid increased to some extent.(2)Two kinds of partridge tea have good scavenging effect on DPPH and ABTS free radicals.The scavenging effects of green tea on DPPH and ABTS free radicals were 133.39mmol/100 g and 139.67 mmol/100 g respectively.The scavenging effects of black tea on DPPH and ABTS free radicals were 149.65 mmol/100 g and 150.88 mmol/100 g,respectively.It shows that fermentation will lead to a slight improvement of free radical scavenging ability of partridge tea.4.The results of macro genome sequencing of partridge tea before and after fermentation showed that the same operational classification units(OTUs)accounted for 16.78% of the total OTUs of bacteria and 22.39% of the total OTUs of fungi.Green tea and black tea had significant differences in microbial flora composition andα diversity index.In addition,there were also significant differences between the two kinds of tea microbial populations,species and indicator genera.