Effects of sun drying combined with baking processes on the flavor quality of Chongqing Tuocha raw tea

The quality of Chongqing Tuocha raw tea (CTRT) processed by different drying methods was analyzed. The results showed that baked then sun-dried (BS) groups sensory score were higher than sun-dried then baked (SB) groups. With baking time increasing, Amino acids levels increased, flavonoid glycosides levels decreased. Umami and sweet Amino acids levels in BS3 group (38.65 and 37.65 mg/g) were 3.27 % and 5.80 % higher than in the BS1 group. Flavonoid glycoside levels were lowest in the BS3 and BS2 (782.92 and 731.49 nmol/g). Argininosuccinic acid, N,N-dimethylglycine, isosilybin, 7,4'-dihydroxyflavone and scutellarin were tightly correlated to bitterness, L-glutamic acid and trans-4-hydroxy-l-proline were closely related to umami. Volatile components content in the BS2 group (62.36 μg/g) was 15.42 % higher than in the SB1 group. Twenty key volatile substances were screened. 1-nonen-3-one, β-Ionone, non-8-enal and trans-beta-ionone were the main aroma contributors for each group. Thus, BS3 and BS2 were favorable to improve CTRT quality.

Baking; Chongqing Tuocha raw tea (Camellia sinensis, Theaceae); Flavor compounds; Sensory quality; Sun drying.