Processing Technology and Quality Evaluation of 'Bashanzao' Purple Bud Leaf Black Tea

In order to explore the processing process of black tea and its preparation of tea from 'Bashanzao' purple bud leaves. In this study, the purple bud leaves of 'Bashanzao' were selected as raw materials, and the process optimization was carried out based on the processing technology of Wanyuan black tea. The key processing technologies of black tea (withering, fermentation and drying) were carried out by single factor experiment and orthogonal experiment. The optimal process parameters of purple bud leaf black tea were determined by sensory score and ratio of the sum of theaflavins and thearubigins to theafuscin TFRB, to explore the effects of different parameters of key processing technology on the quality of black tea. Taking the green buds and leaves of 'Fuding Dabai' as the control, the new shoots of one bud and one leaf were collected and processed into black tea according to the optimized processing technology. The prepared tea sample and 'Bashanzao' purple bud and leaf black tea passed sensory evaluation, determination and analysis of internal quality components and aroma components. The results showed that the optimal processing technology of 'Bashanzao' purple bud leaf black tea was withering time 21 h, fermentation time 4.5 h, drying temperature 90 ± 2 ℃, and the highest sensory score was 92.83 ± 0.19. The sensory quality of 'Bashanzao' purple bud leaf black tea was better than the control. The contents of tea polyphenols, amino acids, soluble sugar, water extract, caffeine, theaflavin and thearubin were 12.58%, 3.62%, 2.89%, 37.89%, 4.61%, 0.38% and 3.57% respectively, which were higher than the control. TFRB was 1.07, which was its fresh taste, the material basis of red and bright soup. The contents of total amino acid components, fresh amino acid components and sweet amino acid components were 32.35, 22.68 and 3.45 mg/g respectively, which were 10.03%, 7.28% and 26.84% higher than the control respectively. 43 aroma components were detected, and the total amount was 57.72 μg/g, 11.67% higher than the control group. The processing technology of 'Bashanzao' purple bud leaf black tea determined in this study has excellent tea quality.