Dissertation
Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > Beverage cold manufacturing industry > Tea > A variety of tea

Relativity Study on the Specific Thermophiles Dynamic Variation with Quality in Puer Tea Pile-Fermentation Process

Author KongXiangJun
Tutor ChenChaoYin
School Kunming University of Science and Technology
Course Biochemical Engineering
Keywords Puer tea Thermophiles Pile-fermentation qPCR Detection
CLC TS272.5
Type Master's thesis
Year 2012
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Puer ripe is a kind of fermentation product which was made of dried crude tea(C. sinensis var. assamica) planted in Puer City of Yunnan. In the current fermentation of Puer tea, pile-fermentation is the key process in which microbial populations have great effect on flavor compound. So microorganisms play an important role in the fermentation of Puer ripe tea. People know little about the functions of microorganisms in Puer tea fermentation due to the limitation of traditional research method. Also, these methods are difficult to reveal the mechanism and detect the microbial population rapidly. Therefore, the study of changes of thermophilic microorganisms in Puer tea fermentation has important sense.In this study, the sequence analysis of16S rDNA and18S rDNA was implemented. The variable regions of Thermoactinomyces thalpophilus, Bacillus boroniphilus, Rhizomucor pusillus, and Thermomyces lanuginosus was sequenced, the characteristic sequences were found and specific primers were designed. The primer specificity was also determined by means of PCR amplification. In the meantime, the characteristic sequences of variable regions were used as template, and real-time PCR was implemented to determine the primer specificity again. The results showed that all the primers had high specificity and real-time PCR was highly specific, highly sensitive and highly accurate. In terms of the data we got, calibration curves were established for the determination of microorganisms in Puer tea fermentation.In order to detect the changes of the4thermophilic microorganisms in Puer tea fermentation, culture-independent approach and real-time PCR were put to use. Several means of the extraction of total DNA of microorganisms in tea samples were compared and the best method was selected. Then the determination of the microbial population was implemented by means of real-time PCR. The results showed that the amount of microbial population changed little at the beginning of pile-fermentation. After turning, the population grew, and reached the highest point at the end of pile-fermentation. Each microbial population was less in amount in mixed fermentation than pure inoculation fermentation. Furthermore, the relation of the four strains and Pu-er tea quality was studied, and the result showed that the four strains, both in mixed fermentation and pure inoculation fermentation, had effect on the amount of tea polyphenols, caffeine, free amino acid and tea pigment.

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