Effects of Shaking Operation on Sensory Quality and Theaflavins in Tanyang Gongfu Black Tea

Objective Effects of varied shaking operation on the sensory quality and formation of theaflavins (TFs) and four monomers of Tanyang Gongfu black tea were analyzed.

Method One bud and two or three leaves were plucked from ‘Jinmudan’ tea bushes and processed under the standard floral and fruity scented Tanyang Gongfu black tea procedure with light, moderate or heavy shaking, along with no shaking as control. The relative contents of total TFs and 4 monomers (i.e., TF1, TF2a, TF2b, and TF3) in the processed teas were determined by HPLC with relative ratios calculated. A sensory evaluation on the tea samples was conducted by a taste panel.

Result The tea made with moderate shaking yielded the highest contents of TF2a, TF3, and total TFs among all samples, while the light shaking produced the greatest TF1 and the heavy shaking TF2b. The sensory evaluation scores were 88.05 on control, 89.45 on the lightly shook samples, 91.35 on the moderately shook teas, and 89.25 on the heavily shook specimens. The panel judged the moderate shaking produced tea tasted more mellow, brighter in color, and stronger on floral-fruity aroma than the other treatments.

Conclusion It appeared that by moderately shaking the leaves in the tea making process, most TFs, TF2a, and TF3 could be formed with improved sensory quality of the resulting tea.