Mixed processing improved the theaflavin, theanine and aroma components of Congou black tea

Congou black tea is mainly processed from single variety leaves, with obvious variety characteristics. This study investigated the effects of mixed processing withered leaves varieties on sensory quality, the volatile and non-volatile compounds of seven Congou black tea samples. Sensory quality evaluation revealed that the Congou black tea with three leaves varieties were fresher, more floral and had coordinate taste. The total quality score was in the order: MPH > H > M&H > M > M&P > H&P > P. However, samples MPH and M&H have a higher content of theaflavins and amino acids, especially theanine. Furthermore, 130 volatile substances were identified in seven black teas by using HS-SPME/GC-MS. M&H and MPH have more aroma types and total amount than that of M, P and H. The mixed processing of withered leaves may fully use the catalysis of endogenous enzymes to increase the 19 kinds of black tea key aromas including Benzyl alcohol, trans-2-hexenyl hexanoate, Hexyl hexanoate and Methyl jasmonate. Thus, blended processing can enhance the taste, aroma and LC quality of black tea.