| Fuzhuan tea is a kind of post-fermented tea.It has unique characteristics due to the fungi growing process,which has the health-care effects of digestion,greasy and lipid-lowering,so it is loved by more and more consumers.With the increasing demand for Fuzhuan tea in the market,there are many problems exist in the production process of Fuzhuan tea,such as lax control of the process and insuffiecient control of quality,resulting in uneven quality of Fuzhuan tea products in the market.Fuzhuan tea originated from Jingyang,shaanxi,Fuzhuan tea industry develops rapidly,but most of its production is still controlled by experience.Insufficient understanding of the species,production conditions and growth patterns of Jinhua fungus leads to unscientific management during the process and the quality of Fuzhuan tea are uneven.How to improve and ensure the quality of Fuzhuan tea is particularly important.In this study,the quality of Jingyang Fuzhuan tea was first analyzed.Secondly,the dominant microbial genus in the Jingyang Fuzhuan tea were isolated and identified,and its characteristics of growth were studied.The pile-fermentation was treated in different ways,and the chemical composition in the process of pile-fermentation and fungi growing was detected.The correlation between the change of the chemical composition content and the growth of Jinhua fungus were analyzed to explore the conditions for the formation of the quality of Jingyang Fuzhuan tea.The results about this research are as follows:1)The quality analysis of 10 samples of Jingyang Fuzhuan tea showed that all of the moisture content of the 10 samples was less than 11.00%.Both the content of water extract and soluble sugar of sample No.8 were the highest,being 33.49% and 13.66±0.04% respectively.The contents of tea polyphenol,flavonoids and theaflavins were the highest,14.55±0.05%,3.50±0.04% and 0.0804±0.0010% respectively.The content of caffeine and free amino acid in sample No.6 were the highest,3.94±0.05% and 0.2876±0.0143% respectively.The highest content of thearin in the sample No.5,it was 1.5425±0.0473%.The highest content of the theabrownine in the sample No.1 was 1.4539±0.0158%.All of the 10 Jingyang Fuzhuan tea samples had the scavenging effect on DPPH,hydroxyl radical and superoxide anion as the concentration of tea soup was 0.004 g/L.Among them,the No.4 sample had the best ability of both superoxide anion scavenging and hydroxyl radical scavenging,and the removal efficiency were 30.50% and 22.39% respectively.It is noteworthy that sample No.9 had the highest removal efficiency of DPPH,and the removal rate was 92.91%.2)The 21 strains of Jinhua fungus were isolated from 10 Jingyang Fuzhuan tea,which were identified as 6 species by molecular biology and morphological,11 strains were identified as Aspergillus cristatus;3 strains were Aspergillus endophyticus;2 strains were Aspergillus appendiculatus;1 strain was Aspergillus intermedius;3 strains were Aspergillus mallochii and 1 strain was Aspergillus costiforme.The salt tolerance experiment showed that two strains of Jinhua fungus F-2(A.intermedius)and J-2(A.costiforme)and a strain of Aspergillus niger can tolerate 155 g/L NaCl,and Penicillium cannot grow in the NaCl whose concentration was higher than 85 g/L.When the NaCl concentration is 155 g/L,the colony of F-2(A.intermedius)is larger than that of J-2(A.costiforme),so it has stronger salt tolerance.The effects of different ways of treatments on the materials in the pilefermentation and fungi growing were as follows: compared with the raw tea,the content of tea polyphenols,soluble sugar,theaflavins and thearubigins decreased in the Fuzhuan tea;the content of caffeine in the untreated group,the strain W-2 treatment group and the mixed treatment group decreased,and the other groups increased;The content of free amino acid of the untreated group increased,and the other treatment groups decreased;the content of the theabrownine in each group increased.The correlation analysis between the growth of Jinhua fungus and the main components in the process of fungi growing showed that the changes of tea polyphenol content,theaflavin content,and the content of thearubigin were Significant negative correlation(P < 0.01),the correlation coefficients were-0.834,-0.703 and-0.837.There was a significant positive correlation between the content of theabrownine and the number of Jinhua fungus(P < 0.01),and the correlation coefficient was 0.825.Therefore,Fuzhuan tea has a great correlation with the growth of Jinhua fungus. |
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