Roles of enzymes in tea: From plant to cup

Abstract

Enzymes are biocatalysts, that increases the velocity or rate of a chemical reaction without undergoing any change in the overall process. Main roles of enzymes are to accelerate a reaction, breakdown compound molecules to its simpler form, regulation of metabolism, maintenance and repair tissues. There are many enzymes present in tea plants which play an important role from growing to processing. Cellulolytic enzyme helps to break the cellulose which help to growth of the plant. Amylase helps to breakdown the starch into simpler sugar and also help in plants defense mechanism. Like that, protease enzyme breakdown the proteins into amino acids, which are essential for various metabolic processes in the tea plant. Phenylalanine ammonia-lyase, Flavonol synthase, Dihydroflavonol 4-reductase etc. are some important enzymes which taking part during the Flavonoid pathway leading to biosynthesis of catechins. Peroxidase and polyphenol oxidase are two major enzymes of black tea processing, which contribute to the colour, flavour, and aroma of black tea (Guo et al., 2021). Other enzymes like lipoxygenase are also responsible for colour and aroma of tea. Theobromine synthase involved in the biosynthesis of theobromine, a xanthine alkaloid that is present in tea leaves, which is responsible for the mildly stimulating effect of tea. β-Glucosidase is an important enzyme in developing the aroma and flavour profile of semi-fermented and fully fermented tea by breakdown of glucosidase bond to aromatic compound (Supriyadi et al., 2021). Catecholase play roles in oxidation of polyphenols in tea, contributing to the characteristic colour and flavour, especially in black and oolong teas. Enzyme role is important as it can enhanced aroma, colour and flavour of tea. As the enzymes are specific to its substrate so by manipulating the enzymes we can produced customized tea which can full fill the demand of modern customer. Also modifying the enzyme activity, we can optimize the antioxidant enhanced tea which is beneficial for health.