Variation of the Polyphenol Oxidase Activity in Tea Leaves (Part 1)

Variation of the Enzyme Activity Concerning the Maturity, Position of Leaf, Season, Year and Clone

Abstract

The variation of polyphenol oxidase activity in the tea leaves was examined, concerning maturity, position of leaf on the shoot, plucking season, year and clone.
The enzyme activity, indicated by the oxygen uptake (μl) per 10 mg of acetone powder(I) showed a decreasing tendency with the development of shoot. The specific activity indicated by the oxygen uptake (μl) per mg of acetone-insoluble N (II) of the clones Benihomare and Benitachiwase showed an increasing tendency with the development of shoot. But the variation was slight up to about 50% of debiraki-do in every clone.
The first leaf of shoot had a highest enzyme activity (I) and the fourth leaf had a low activity. The stem had a very higher specific activity than the leaves.
Among the clones, ANAN 1671 and Hatsu-momiji had low activities while Benihomare, Benikaori and Indo had high ones in every year.
The enzyme activity (I) in the leaves of the second season was higher than that in the other two seasons, but the specific activity (II) of the third season was as same as the second.
Correlations between the enzyme activities (I, II) and the qualities of black tea made by the Raikai method were observed all the year round but not in each plucking season.