Research On Isolation, Identification And Function Of Funguses In Dark Brick Tea

Dark Brick Tea is a kind of tea shaped brick by vapor treating Raw Dark Green Tea in high-temperature. The quality of Dark Brick Tea is greatly influenced by the microbe in its making process. The quality of Fu-Zhuan Brick Tea is directly affected by the quantity of Eurotium-cristatum. From the 1950s to now, various kinds of funguses had been isolated from some kinds of Dark Brick Tea. In this research, Dark Brick Tea, was taken as the material and the result was as following:(1) Five kinds of funguses marked Strain A, Strain B, Strain C, Strain D, and Strain E were isolated from Dark Brick Tea by inoculating the sifting teas on PDA culture medium plate. The isolated funguses were inoculated on five different kind of culture medium plate, by measuring their diameters, the soluble starch culture medium were identified as the best culture medium of the five kinds of funguses. In further research, by altering the temperature and pH,30℃and pH6.5 were identified as the best culture condition of the isolated funguses.(2) The characteristics of the five funguses were observed by optical microscope and electronic microscope and the spore of the funguses were taken photograph. By comprehensively analyzing the colony character and the microscopic images, the result showed that Strain A was identified as Aspergillus-tubingensis, Strain B was identified as Eurotium-amstelodami, Strain C was identified as Penicillium-meleagrinum, Strain D was identified as Eurotium-cristatum, and Strain E was identified as Aspergillus-niger.(3) The genomic DNA of the five funguses were extracted, by amplifying and measuring their ITS sequence, in base of their ITS sequence, the Phylogenetic trees of the five funguses were constructed. The result of molecular identification showed that Strain A was identified as Aspergillus-tubingensis, Strain B was identified as Eurotium-chevalieri, Strain C was identified as Penicillium-meleagrinum, Strain D was identified as Eurotium-cristatum, and Strain E was identified as Aspergillus-awamori. By analyzing the result of molecular identification combined with morphological identification, Strain A was identified as Aspergillus-tubingensis, Strain B was identified as Eurotium-amstelodami, Strain C was identified as Penicillium-meleagrinum, Strain D was identified as Eurotium-cristatum, and Strain E was identified as Aspergillus-awamori.(4) To further study the functions of funguses isolated from Dark Brick Tea on human indigestion system, the five identified funguses were fermented singly and mixed. The content of tea polyphenols, tea polysaccharide, catechin, and free amino acid in the fermentation liquor were measured. At last, by imitating the human indigestion system, the influence of amylase, pepsin, trypsin, and lipase that caused by the single or the mixed fermentation liquor was researched. The result showed that it was the metabolites produced by the isolated funguses by using the nutrient component in Dark Brick Tea to improve human indigestion.