Abstract: By using of two leaves and a bud shoot as fresh tea leave material, setting three different withering temperature (20, 28, 36℃), sampled leaves with different moisture content, then the contents of tea polyphenols, total amino acids, flavonoids, total soluble protein, soluble sugar, PPO activity, and POD activity were determined to study the effect of withering temperature on dynamic changes of main biochemical components and enzymatic activity of tea fresh leaves, and the effects of different withering temperature on main biochemical components of rolled leaves, fermented leaves and fired tea were also analysed. The results show that with the increasing of withering time, moisture content of tea fresh leaves decrease gradually, the contents of tea polyphenols, total soluble protein and soluble sugar decrease gradually accordingly, and the contents of tea polyphenols were no difference between 28℃ and 36℃, but are obviously higher than that in 20℃; the contents of soluble protein and soluble sugar are negatively correlated with temperature; the contents of total amino acids and flavonoids increase gradually, and are positively correlated with temperature; the released amount of CO2 decreased at first, then increase and decrease finally, and the amount is the largest when the withering light temperature is 36℃; polyphenol oxidase activity shows a slow downward trend, peroxidase activity shows an upward trend, and they are the highest at 28℃. The contents of theaflavins, thearubigins, and polyphenols are also the highest at 28℃; the results of sensory evaluation also shows that the liquor color and taste of black tea at 28℃ had the highest score, with the best quality.

Key words: withering, temperature, biochemical components, enzymatic activity, dynamic change