The Improvement of Phenolic Contents, Antioxidant Activity, and the Appearance of Black Tea Extract by Combination Viscozyme and Tyrosinase Addition

The problem with ready-to-drink (RTD) black tea is a long manufacturing process and contains phenolic compounds and low antioxidant activity due to the enzymatic oxidation process. Viscozyme is an enzyme that degrades plant cell walls during extraction so that it releases active components from the cell wall, such as phenolic contents and antioxidant activity. Meanwhile, tyrosinase includes the polyphenol oxidase enzyme, which can take advantage of catechins conversion into theaflavins and thearubigins. This study aimed to determine the addition of viscozyme and tyrosinase combination to increase the content of phenolic compounds, antioxidant activity, and improve the appearance of black tea (color). The study used young leaves that had their enzymes inactivated was added with viscozyme to fresh tea leaves extract. The tea extract that had been given viscozyme was then added with tyrosinase, and the incubation was carried out. The addition of tyrosinase with higher concentrations (3,571 U/mL) and longer incubation times (40 min) decreased total phenolic contents, antioxidant activity using DPPH free radical scavenging method, increased tea cream formation (precipitation that forms as the tea cools), the compound of theaflavins, thearubigins, and TF:TR ratio (comparison of theaflavins and thearubigins contents) in tea extracts that had been treated with viscozyme. The combination of viscozyme and tyrosinase gave higher total phenolic compounds, antioxidant activity, theaflavins, thearubigins content, and TF:TR ratio compared to control and could prevent the formation of tea cream. The use of viscozyme 250 µL and tyrosinase 3,571 U/mL for 20 min on ready-to-drink black tea gave the best effects in this study. © 2025, Walailak University. All rights reserved.