ABSTRACT
Theaflavin (TF) is a component of fermented (enzymatic oxidation) catechin compounds synthesized during tea leaf fermentation, giving a golden yellow color, taste, and aroma to black tea. Theaflavins, which are rich in antioxidants, can treat cancer, obesity, diabetes and are potential as an inhibitor in SARS-CoV-2. Photo fermentation using ultraviolet (UV) has the advantage of penetrating the stoma cell wall in tea leaves and accelerating the oxidation of tea leaves that have gone through the milling process before the fermentation stage. This study aimed to optimize the photo fermentation process of theaflavin compounds from fresh tea leaves through response surface methodology (RSM). The highest theaflavin was obtained at a flow rate of 6 L/minute and a long irradiation time of 55 min, with a theaflavin content of 0.6705%. RSM states that the oxygen flow rate is the most influential factor with an R-Square value of 0.60814 means only 60.814% variation in data can be described by the model. (C) 2022 The Authors. Published by Elsevier Ltd.