Microorganisms Of Pu-er Tea Fermentation

In this paper,the analytical method of and determination method of active ingredients in Pu-er tea was established.And the microorganisms in fermented tea was isolated and identified,and new fermentation process of Pu-er tea was studied.The polyphenols content was determined by high performance liquid chromatography(HPLC),the results showed:commercially available green tea contained gallocatechin(GC),epigallocatechin(EGC),epigallocatechin gallate(EGCG),epicatechin(EC),epicatechin gallate(ECG)and other tea polyphenols,Gallic acid(GA)and Caffeine(CAF).EGCG were the main content of active ingredients in the four kinds green tea.All the seven kinds of active ingredient in "Semi-fermented" tea Tieguanyin were all detected.The content of EGCG was highest up to 16.610 mg/g.Polyphenols(catechins)in "Fermented" black tea were partially degraded.The content of GC,EGC,EGCG were low.The content of caffeine was highest up to 17.304 mg/g.The contents of EGCG and ECG in Dianhong tea were 4.588 mg/g and 3.559 mg/g,respectively.The main active ingredients in Pu-er tea were gallic acid and caffeine.The other five tea polyphenols were almost undetectable in the raw green tea.Catechins and effective components have all been degraded.Leaching rate was determined by difference method:the leaching rate of non-fermented green tea is the highest,39.28%,followed by the semi-fermented Pu-er tea.Determination of tea color:the OD value of green tea under the 482nm and 402nm wavelengths were the lowest.The OD values in canned Pu-er tea were the highest.The determination of solublesolids content:soluble solids in 200mL filtrate of non-fermented green tea is highest up to 1.76g,followed by black tea and Dianhong tea.The soluble solids contents of the fermentation tea were all reduced.Based on the traditional natural fermentation,the microflora in traditional natural fermented Pu'er tea and machine fermented Pu'er tea were separated and identified:the ratio of dominant strains of bacterias in the traditional fermented tea Aspergillus niger:Aspergillus japonicus:Penicillium:uncertain species was 11:6:1:1.In the machine fermented teaAspergillus niger:Aspergillus japonicus:uncertain species was 14:8:1.In accordance with the above two percentage,inoculating seeds were prepared and were compared with the non-inoculated test.The results showed:the quantitative relationship of the dominant strain in the 2 batches was:Aspergillus niger>Aspergillus japonicus>Penicillium>uncertain species,Aspergillus niger and Aspergillus japonicus were the main species.The natural fermented tea and the not inoculated tea had the similar trend of temperature change in fermentation process.The optimum fermentation temperature was 45?~55?.The fermentation period was 16d.The medium containing Little Pearl barley and tea,inoculation ratio of traditional natural fermentation of tea for the 3rd batche fermentation.The quantitative relationship of dominant bacteria,temperature trends and the fermentation period were almost the same with previous 2 batches.The effective components in Pu-er tea were determined by HPLC.All of the 3 batches fermented tea contained caffeine and gallic acid mostly.Other active ingredient content of catechins were little or almost absence.The gallic acid content in Little Pearl barley inoculated fermented tea and tea inoculated fermented tea had increased highly than the previous 2 batches,accounting for 3.29%and 2.33%.Other ingredients in tea were determined,the results were:water content of Little Pearl barley tea inoculated fermented tea was 2.52 at least.The leaching rate in tea inoculated fermented tea was the lowest,only 16.03%.Tea inoculated fermented Pu-er tea had the highest OD,color maximum was 2.295.Soluble solids content in 200mL filtrate of inoculated fermented tea was the lowest,0.96g.The microbial flora in natural fermentation tea was separated and identified for the determination of the dominant species.And artificial inoculated fermented through the proportion of advantage bacteria.By the application of this method in fermentation,the time is reduced to 15-20d.That overcomed the defects such as the long fermentation cycle in traditional fermentation,unstable product quality,too much bacteria,and large blindness,etc.