Metabolic Profiling Reveals The Optimal Processing Technique On The Main Characteristic Metabolites Of Congou Black Tea

The processing of black tea choose proper tea sprout as raw material, including withering, rolling, fermentation, drying. The characteristic ingredients, which are formed in the processing of black tea, are very important in the color, aroma and flavor of Congou black tea. In this paper, two leaves and a bud were chose as the research system. The Congou black tea of different processing technique, measured by single factor and orthogonal experiments, is analysised by the metabolic profiling and the sensory evolution. The metabolic profiling includes the non-targeted analysis and the targeted analysis. The untargeted profiling analysis is the non-polar phase and polar phase from Congou black tea of difference processing technique by GC-MS. The date in mass spectrum was analyzed and identified based on NIST and Wiley database. The difference between Congou black tea of different processing technique was measured by PCA and PLS. The targeted profiling analysis means analysis of amino acid, catechins, caffeine and flavonoids from Congou black tea of different processing technique by HPLC. significance test of different influence in amino acid, catechinic acid, alkaloid, flavone of diverse processes which was measured from SPSS software. In the sensory evolution, the quality of Congou black tea of different processing technique depends on comment and grade. The main results are as following:The contents of volatile composition in Congou black tea of different processing technique are very different. The main contents of volatile composition are unsaturated alkyl hydrocarbon, saturated alkyl hydrocarbon, acids, alcohols, ketone, aldehydes and esters. In the orthogonal experiment20kinds of VIP component information are got from PLS-DA analysis and identification. The content in group A2B1C2and A2B3C1are high. So they are the better processing technique.In the single factor experiment20kinds of VIP component information are got from PLS-DA analysis and identification. The content in black tea under sun withering and1.5h sun withering and indoor withering are high. So they are the better withering factors. The content in black tea under freeze drying and the freeze drying after baking are high. So they are the better withering factors.The differences in contents of non-volatile composition in Congou black tea of different processing technique are little. The main contents of non-volatile composition are sugars, acids, alcohols. In the orthogonal experiment20kinds of VIP component information are got from PLS-DA analysis and identification. The content in group A2B1C2and A2B3C1are high.So they are the better processing technique.In the single factor experiment20kinds of VIP component information are got from PLS-DA analysis and identification. The content in black tea under1.5h sun withering and indoor withering and sun withering are high. So they are the better withering factors. The content in black tea under105℃then60℃drying and90℃drying are high. So they are the better withering factors.The contents of amino acid in Congou black tea of different processing technique are very different. Leu, L-The, Pro, Glu, Asp and Ser are all in high content. In the orthogonal experiment the content in A3B3C2are the higher than in A1B2C2while A2B2C3and A3B1C3are the lowest. In single factor experiment content in blast withering is the highest. Next is the freeze-drying after baking group, the tea with freeze-drying and90℃drying are the lowest.The contents of catechins, caffeine, flavonoids in Congou black tea of different processing technique are various. The contents in A1B1C1are the highes, the next is A2B1C2, A3B1C3and A2B3C1are the lowest. In single factor experimenthet content in black tea with1.0h sun withering and natural withering is the highest, the next is under1.5h sun withering and natural withering, the90℃drying and105℃then60℃drying are the lowest.In the sensory evolution of Congou black tea of different processing technique the assessment in A2B1C2, are the best. The next one is A1B3C3, A1B1C1and A2B3C1are the lowest. In single factor experimenthet content in black tea with sun withering is the highest, the next one is90℃drying, the tea with freeze-drying after baking and freeze-drying are lowest.In summary,In the orthogonal experiment A2B1C2is the best processing technique.In the single factor experiment the black tea under sun withering is the best withering factor and105℃then60℃drying is the best withering factor.