ABSTRACT
We determined the molecular weight and some properties of multiple forms of phenol oxidase from tea leaves and four other perennial plants. It was shown that multiple high- and low-molecular forms of phenol oxidase differed in substrate specificity. Low-molecular forms of the enzyme mostly demonstrated hydroxylase activity, while high-molecular forms showed catechol oxidase activity. It was revealed that the withering stage of black tea production is accompanied by the formation of only high-molecular forms of phenol oxidase, which possess catechol oxidase activity crucial for the procurement of oxidative reactions and the quality of the product.
Subject(s)
Camellia sinensis/chemistry , Monophenol Monooxygenase/chemistry , Plant Leaves/chemistry , Plant Proteins/chemistry , Tea/chemistry , Catechol Oxidase/chemistry , Desiccation , Food Technology , Isoenzymes/chemistry , Mixed Function Oxygenases/chemistry , Molecular Weight , Oxidation-Reduction , Substrate SpecificityABSTRACT
The possibility to regulate phenoloxidase activity with sulfur dioxide was studied. It was found that this compound is a potent inhibitor of phenoloxidase of the reversible and mixed type. The inhibitory effect of sulfur dioxide on phenoloxidase provided grounds for a new biotechnological approach to the production of instant green tea. This approach allows increasing the yield of the extractive and the proportion of phenolics in the extractive, thereby improving the organoleptic quality of the product.
