Separation Of "Junhua Fungi" From Fuzhuan Tea And Their Fermentation Character Analysis

Fuzhuan Tea is a kind of fermented tea,which can promote digestion and reduce blood lipid and glucose.A large number of gold particles which known as “Jinhua Fungus” was included in the Fuzhuan Tea.“Jinhua Fungus” is the key factor indicating the quality of Fuzhuan Tea.It is also an important symbol to distinguish with other kinds of tea.At present,with the demand of health,more and more consumers focus on the Fuzhuan Tea,in addition,many governments regard Fuzhuan Tea production as one of the pillar industries to drive the development of local economy.But many questions with the “Jinhua fungus” were not clear at all,including their classification,composition,colony characteristics,fermentation characteristics and detection methods.In current study,taking Fuzhuan Tea in shaanxi province as raw material,the “Jinhua fungus” was separated and purified with dilution-plate method.With the purified “Jinhua fungus”,kinds of Fuzhuan Tea fermentation agent was prepared for artificial inoculation test.In addition,changes in the content of the main functional components,including tea polyphenols,EGCG,caffeine,tea polysaccharide,tea pigmentands etc.were detected by HPLC and UV etc.,which can explore the relationship between “Jinhua Fungus” and the quality of Fuzhuan Tea.The main results was showed as follow:1.By streak plate method,slide culture method,microscopic observation and the antagonistic test,the microorganism existed in Fuzhuan Tea were separated and identified.The results showed 12 fungal strain were selected preliminarily,which were “Jinhua Fungus”,which were identified preliminarily as Eurotium fungus according to the morphological character of conidiophores and ascocarps,in which 70% of them were Eurotium cristatum.The spores of “Jinhua Fungus” is spherical or ellipsoid with the diameter of 4.2~5.1 μm,the centre of spores were green and the edge of spores had an obvious coronary construction,or the surface of spores were smooth.Fuzhuan Tea samples pretreatment conditions were optimized by using single factor test and response surface analysis method.The results showed that the optimum conditions of sample pretreatment were that 180 mesh,the ratio of solid to liquid was 2%,the concentration of Sodium chloride dilution was 0.85%,the water bath temperature was 35℃,oscillation time was 40 min.With these conditions,the number of living “Jinhua Fungus” got from the plate counting method was(15.40±0.41)×106 CFU/g,the number of spores got from blood cells counting method was(15.53±0.24)×106 /g.Compared with the numerical prediction of response surface model,the RSD value of the amount of living bacteria was 0.41%,the RSD value of the amount of spores was 0.24%,far less than 3%.Therefore,the above conditions can be used as the best parameters for pre-treatment of Fuzhuan Tea samples.Compared with the plate counting method,the blood cell counting method has the advantages of convenience and quickness,and the data were accurate and reliable,so it is more suitable to the detection of “Jinhua Fungus” in the Fuzhuan.2.The artificial inoculation experiments were carried out with the fermentation agents prepared with the purified “Jinhua Fungus”.Results that the “Jinhua Fungus” in the Fuzhuan Tea inoculated with fermentation agent after second steam grew rapidly in the days from 2 to 8.When 8 day after the inoculation,the amount of “Jinhua Fungus” were(4.50±0.11)×106 CFU/g,however,the number of “Jinhua Fungus” in CK reached(4.20±0.13)×106 CFU/g at 14 th day.After 10 days,the number of “Jinhua Fungus” of inoculation Fuzhuan Tea maintained at 5.74×106 CFU/g,the growth of number were not obvious.So the artificial inoculation “Fungi-growing” method is advanced 6 days and shortened to 10 days.The contents changes of main functional components such as tea polyphenols,EGCG,amino acid and caffeine were negatively correlated with the quality of “fungi-growing”.The EGCG,free amino acid,tea polyphenols and caffeine were decreased by 77.38%,44%,31.50%,13.50% respectively in the inoculation treated group,in addition,these components were reduced by 64.15%,35.29%,26.24%,11.01% in the CK,respectively.Tea polysaccharide content increased initially and then decreased,which showed its positive correlation with the number of “Jinhua Fungus” before the middle period.The tea polysaccharide content was 5.08% higher after fermentation than in the raw materials.Theaflavins was decreased 20% ~ 25% after “Fungi-growing”.Thearubigin was decreased 57.03% and 49.96% in inoculation treated group and CK group,respectively.In addition,theabrownine always increased during the “Fungi-growing” process.Its content is in the final product was 1.5%~2.8%.The water extracts content rised 7.11% after fermentation,while CK rised 0.91%.Sensory evaluation results indicated that the “Jinhua Fungus” was richness in inoculation of tea bricks.The taste of inoculation of tea was much better,without bitterness.The soup color of control group is orange,aroma of “Jinhua Fungus” was much lighter and the smell of black tea is not completely transformed.Totally,inoculation of fermentation agents could increase the quality of Fuzhuan tea.