Immobilized polyphenol oxidases (IPPO) was applied for the synthesis of theaflavins using tea catechins as substrates. A Response Surface Methodological (RSM) study was conducted using a five-level, five-variable, central composite rotation design (CCRD) to select the optimum catalysis conditions for theaflavin transformation from tea polyphenol through immobilized enzyme membrane. Five important variables were considered, namely, incubation duration, enzyme/substrate ratio (E/S, Activity Units/ml-AU/ml), a...