Microbial Community And Function Material Composition Analysis For Pu'er Tea From Different Ferment Time

Pu'er tea is post-fermented tea and has a variety of health care functions for human body,such as lowering blood pressure,lowering blood fat,reducing weight,moderating the risk of cancer,and preventing cardiovascular disease.During the whole ferment process,the biotransformation reaction of microorganisms can affect the function material and the formation of pu'er tea quality.So the study of the change of microbial community and function material in pu'er tea pile fermentation process will be usefull to enhance the cognition of pu'er tea fermentation and provide the theoretical basis for the further improvement of pu'ertea processing technology.The main results were as follows:The microbial community from 15 day and 30 day pu'er tea sample was analyzed by high-throughput sequencing firstly,and 385312 Unigenes were obtained.The comparing results of COG database showed that Unigene main enrichment in amino transport and metabolism,carbohydrate transport and metabolism,inorganic ion transport and metabolism,replication,recombination and repair.The compareing results of Nr database,showed that Unigene mainly distributed in opisthokonta(including fungi),actinobacteria,firmicutes,proteobacteria,bacteroidetes,viridiplantae.1344 Unigene were identified to species,46.61%of Unigene belong to fungi,29.55%belong to bacteria.The species proportion more than 1%was Aspergillus kawachii,Debaryomyces hansenii,Aspergillus fumigatus,Brachybacterium faecium,Microbacterium testaceum,Aspergillus niger,Bordetella petrii,Neosartorya fischeri.The compareing results of rDNA database showed that the species detected were fungi,opisthokonta,unclassified,proteobacteria,firmicutes,metazoan,viridiplantae,archaeplastida,bacteroidetes,SAR.The proportion of bacteria were higher than fungi in 15,30 day pu'er tea sample,the proportion of bacteria from 28.33%rise to 34.38%,fungi from 18.16%rise to 19.15%.The quantitative analysis of probiotic groups number from different ferment time pu'er tea sample were determined by real-time PCR.The results showed that the content of all bacteria,enterococcus sp.,lactobacillus sp.,lactococcus sp.and bacillus sp.had different degree change with the extension of ferment time,the peak value were 9.97×1018 copy/g,1.29×1015 copy/g,3.05×1013 copy/g,1.6×1015 copy/g and 6.0×1013 copy/g,respectively.Meanwhile,this 4 species had been involved in the ferment process of pu'er tea,and enterococcus sp.and lactococcus sp.were main probiotics.The kind and content of tea polyphenols of pu'er tea samples in different ferment time were analyzed by HPLC.The results showed that the content of gallic acid,ECG and EC increased from 0 day to 15day,and then decreased gradually.The content of EGCG increased with the extension of ferment time.The kind and content of volatile aromatic of pu'er tea sample in different ferment time were analyzed by GC-MS.The results showed that the volatile aromatic included 35 kinds of Hydrocarbons,16 alcohols,3 aldehydes,11 ketones,9 methoxy benzenes,10 eaters,2 phenols,10 alkenes and others kind.Hydrocarbon,alcohols and methoxy benzenes was the most abundant in pu'er tea pile fermentation.