Study On Dominant Flora And Its Function Of Fuzhuan Brick Tea Produced In Shaanxi

Fuzhuan Brick Tea is fermented by a variety of microorganisms and belongs to the typical Chinese dark teas.It has a special flavor and is beneficial to human health by long-term drinking."Golden Flower Fungus" is the dominant flora in Fuzhuan Brick Tea,which is closely related to the quality,flavor and functional activity of Fuzhuan Brick Tea.The quantity of"Golden Flower Fungus" is also an important indicator for quality inspection of Fuzhuan Brick Tea.Shaanxi is the birthplace of Fuzhuan Brick Tea,but the systematic identification and the functional study of dominant"Golden Flower Fungus" are few.This study analyzed the the quantity of the"Golden Flower Fungus" and functionality in the Fuzhuan Brick Tea during flowering and the representative Fuzhuan Brick Tea produced in Shaanxi,and combined the morphological,ITS,and 18S rDNA methods to identified the isolated dominant"Golden Flower Fungus" ,then systematically study the functionality of the representative"Golden Flower Fungus" .It provides the basis for the identification of the"Golden Flower Fungus" ,the exploiting and using of"Golden Flower Fungus" resources in Shaanxi province and the standardized production of the Fuzhuan Brick Tea.The research results are as follows:Changes in the quantity of"Golden Flower Fungus" and functionality of Fuzhuan Brick Tea during the flowering process.The high quality tea brick made of pressed Fuzhuan Brick Tea was placed in incubator for 28 days,and samples were taken at 0,2,4,6,8,10,12,14,16,18,23,28 d during the flowering process to determine the quantity of"Golden Flower Fungus" ,phenolic substances,tea pigments and antioxidant activity.It was found that the number of"Golden Flower Fungus" increased gradually from the 6th day of flowering,and the quantity of"Golden Flower Fungus" in the finished brick tea was up to 5.30lg?CFU/g?.With the increase of the number of"Golden Flower Fungus" ,the content of flavanol and theabrownins also increased,the final content was 0.81%and 2.71%,respectively;the content of tea polyphenols,flavonoids,theaflavins and thearubigins decreased by 31.37%.35.27%,49.31%and 57.59%;DPPH free radical scavenging rate and reducing power first increased and then decreased,peaking on the 6th day of flowering,75.61%and 121.87?gV_C/mL,respectively.Study on the quantity of"Golden Flower Fungus" and functionality of Fuzhuan Brick Tea.Firstly,the number of"Golden Flower Fungus" ,the content of tea polyphenols,DPPH free radical scavenging rate and reducing power of 10representative samples produced in Shaanxi were determined.The results showed that the indexes of 10 samples were significantly different at the level of p<0.05.The indexes of JZKPE were higher than those of other Fuzhuan Brick Teas.Then,JZKPE was treated by two soaking methods:brewing method and boiling method.The quantity of"Golden Flower Fungus" in tea residue and tea soup,phenolic substances,tea pigments and antioxidant activity in tea soup were determined.It was found that the number of"Golden Flower Fungus" in tea soup and tea residue after brewing was 4.08 lg?CFU/g?and 5.12 lg?CFU/g?,respectively,higher than that of boiling method.The difference was significant at p<0.05 level.DPPH free radical scavenging rate,reducing power,tea polyphenols,flavonoids,flavanols,theaflavins,thearubigins and theabrownins in boiled tea soup were 84.67%,102.03?gV_C/mL,2.43%,0.04%,0.23%,0.08%,1.44%and 3.90%,respectively,which were higher than those in brewing method,and had significant difference at p<0.05 level.Finally,it was found that the survival rate of"Golden Flower Fungus" in tea soup could still reach 83.40%after incubation in simulated gastric juice for 3 h and 66.24%after incubation in simulated intestinal environment for 6 h.Analysis of the diversity of fungal community in Fuzhuan Brick Tea.Illumina Miseq High-throughput Sequencing Technology was used to obtain sequences of ITS1 region of 10 Fuzhuan Brick Tea,and the sequence was analyzed by bioinformatics.The results showed that there are fewer fungal species in 10 kinds of brick tea,and they all contain"Golden Flower Fungus" ,A.niger,and A.alternata.Among them,"Golden Flower Fungus" is the dominant flora in Fuqian tea.The abundance of"Golden Flower Fungus" is over 98%.By compared with UNITE and NCBI,“Golden Flower Fungus" may be A.chevalieri,A.amstelodami,A.montevidensis,A.cristatus,A.spiculosus,A.cibarius,E.amstelodami,E.rubrum.Isolation and identification of"Golden Flower Fungus" from Fuzhuan brick tea.8 dominant"Golden Flower Fungus" were isolated from 10 Fuzhuan brick tea.According to the colony characteristics,the sexual and asexual reproductive characteristics of 8 strains on CZG,CZG20,CZG40,CZ,CZ40 and PDA media,ITS sequencing,alignment and phylogenetic analysis,18S rDNA sequence detection,alignment and phylogenetic analysis,J1 was identified as A.chevalieri,J2,J3,J4 and J7 were identified as A.cristatus,J5 was identified as A.amstelodami,J6 was identified as A.costiformis,J8 was identified as A.pseudoglaucus.Antioxidant activity of"Golden Flower Fungus" in Fuzhuan brick tea.Five strains of"Golden Flower Fungus" :J1,J2,J5,J6 and J8,which were identified as different species,were inoculated on CZG and PDA media respectively.They were cultured at 28?for 21 days.The phenolic substances,tea pigments and antioxidant activities of the five strains were determined at 10 time points during the culture period.The results showed that five strains in PDA and CZG medium could produce phenols and tea pigment and had certain antioxidant activity.Among them,J2 strain on PDA medium had better antioxidant activity.The highest contents of tea polyphenols,flavonoids,flavanols,theaflavins,thearubigins and theabrownins were 1.28 mg/g,0.12 mg/g,0.03 mg/g,1.77%,1.26%and 11.21%respectively,and the highest scavenging rate of DPPH free radicals and reducing power were 86.35%and 72.50?gV_C/mL,respectively.Antimicrobial Activity of of"Golden Flower Fungus" in Fuzhuan brick tea.Firstly,the bacteriostatic activities of J1,J2,J5,J6 and J8 strains on CZG and PDA media against Escherichia coli and Staphylococcus aureus were determined by the method of agar plate antagonistic method and filter paper disc method.It was found that five strains all have bacteriostatic activity,and the bacteriostatic activities of J2 strain against Escherichia coli and Staphylococcus aureus were the best.The antimicrobial activities against E.coli and S.aureus were11.15¹9.84 mm and 12.65²5.72 mm,respectively;According to preliminary analysis,the antimicrobial substance contains the functional groups of tea polyphenols,Ar-OH,Ar,-CH₃,C=O,C-O-C,and C-H.Functional changes during liquid fermentation of J2 strain.J2 strain was cultured in PDA and CZG liquid medium at 28 C for 15 days.The functional changes of J2 strain were measured at 6 time points during the culture period.The results showed that the function of PDA fermentation broth of J2 strain was better than that of CZG fermentation broth.DPPH free radical scavenging rate and reducing power of PDA fermentation broth were 98.74%and 113.43?g V_C/mL respectively on the 15th day of fermentation.At this time,The inhibitory circles against E.coli and S.aureus were 10.05 mm and 19.63 mm,respectively.The mycelial activity of J2 in CZG fermentation broth was higher than that in PDA fermentation broth.The best DPPH free radical scavenging rate and reducing power were 95.12%and 119.60?gV_C/mL respectively.The maximum diameter of the inhibition zone for E.coli and S.aureus was 16.31 mm and 20.30 mm,respectively.