Analysis of main chemical components of Qingzhuan tea in different layers during piling-fermentation
In this study,the piling-fermentation of Hubei Qingzhuan tea in factory scale was studied to explore the changing rules of the chemical components and sensory quality in different lay-ers during piling-fermentation.The results showed that the chemical components were significantly changed during piling-fermentation,especially in the early stage of piling-fermentation,in which the contents of water extract,free amino acids,tea polyphenols,theaflavins(TFs),and thearubi-gins(TRs)in Qingzhuan tea all decreased,and the content of theabrownines(TBs)increased.A-mong different layers,the contents of water extract,free amino acids and soluble sugar in the upper layer both were lower than those in the middle and lower layers.The content of TFs in the upper layer was higher than those in the middle and lower layers during the early stage of piling-fermentation,but the content of TBs in the lower layer was lower than those in the middle and upper layers.The color of tea soup converted from orange-yellow to orange-red,the color of residue leaves was drastically changed from yellow-green to liver color with some mixed color,and the aroma is mainly composed of oil smell in this process;The sensory quality of the upper tea sample is generally higher than that of the middle and lower layers.The piling-fermentation of Qingzhuan tea was classified into three periods by clustering analysis:the first period(Ⅰ)was at the beginning of piling-fermen-tation(0 d),the second period(Ⅱ)was the early stage of piling-fermentation(3～6 d),and the third period(Ⅲ)was the later stage of piling-fermentation(9～24 d).It was indicated that 9 d was the proper time for the piling-fermentation of Qingzhuan tea for the chemical components transformation and quality had been basically completed before the first turn(0～9 d),which pro-vided a theoretical basis for the improvement of the piling-fermentation process of Qingzhuan tea.
万方数据
维普
