Identification Of Fungal Colonization Of Sichuan Kangzhuan Tea During Pile-fermentaion

Sichuan Kangzhuan tea is one kind of Sichuan south-road tea, and is kind of dark tea of six kinds. The Sichuan south-road brick tea is a unique type of tea in our country, and it has the massive historical connotation and the cultural deposits. It was still the Tibetan compatriots necessities of life. Pile-fermentation was considered the pivotal process which forms the unique quality of the brick tea. There are two kinds of faction about the quality formation mechanism:the one, some scholars think that humidity effection make the material transformation good quality components, eg:Ya'an tea factory using the "High-temperature moisture" to product Sichuan kangzhuan tea; the others think that microbiology secrete extracellular enzyme to promote physical transformation, eg:using the manner of "Inoculate microbiology to promote fermentation" to product pu'er tea. Another, there also is the report that using the tenderness of raw materials and inoculate mocrobiology to reduce fluoride content during the fermentation. In rencent years, most of academic achievements think that the mechanism is the microbiology. During the fermentation, many microbiology are fit for the environment, they secrete some kinds of extracellular enzymes to promote physical transformation and polymerization. Finally, the dark tea generate his typical quality. Sichuan Kangzhuan tea has thousands years histories, but has been little research about microbiology, except observation the colony. In this paper, using the Sichuan Kangzhuan tea as experiment meterial, according the five-point sampling method, fetching sample respectly form 5,20,40,80cm of fermentation-pile. Choose the best depth sample according sensory evaluation and quality analysis, and separate ang purificate the microbiology from the choosed-sample. Making the fure fungal become fitted sheet and microscope, and study the morphology. Carried out tea tolerance test, high temperature tolerance test, production of organic acids test, liquid fermentation testing for purification and various strains to choose the dominant fungal. Carried out liquid culturl for the choosed dominant fungal, extracted the DNA from mycelium, used the primer to product ITS sequence, sequencing the PCR products by biology company, blasted the results with NCBI, defined the taxonomic status of fungal populations. Trough the identified the fungal and studied physiological characteristics to define the dominant fungal, with a view that provied evidence for the quality mechanism of Sichuan Kangzhuan tea. 1. Diffrent depth has diffrent quality during the fermentation, the best is 40-80cm. There are a low level of polyphenols, amino acids and high content of water extract. Sensory quality show that liquor color is orange-red and bright and aroma is rich and aging.2. Morphological study showed that there are 12 kinds of fungi from Aspergillus, Mucor, Thamnidium, Rhizopus four categories.3. Advantages fungi identification showed that the fungi in the tea-rich solid and liquid growth medium volume inconsistencies. Existenced some strains producing organic acids, and the acid-producing inconsistent results. All the fungal strains'maximum temperature below 65℃. Initially identified five predominant strains. Search the predominant strains of the information, analyze the quality of the formation mechanism may be as follows: Aspergillus niger producing a variety of extracellular enzymes, from different angles to promote the quality of conversion; Aspergillus tubingensis, Aspergillus carbonarius, Rhizopus oryzae for production of extracellular pectinase into pectin rich water extract; Rhizopus oryzae, Mucor racemosus produced extracellular protease formation of amino acids to promote protein breakdown.4. ITS sequence analysis showed that five advantages of fungal strains were:Aspergillus niger, Aspergillus tubingensis, Mucor rouxianus, Aspergillus carbonarius, Rhizopus oryzae.5. There are some differences fungal Colonization between Sichuan Kangzhuan tea with pu'er tea from Zhen-jun Zhao's study. Considering the possibility is that different kinds of Black Tea has different fermentation environment, different environment has different fungi, different fungi will be direct different qulilty.