Determination of phenolic compounds in wines with enzyme electrodes fabricated by immobilization of polyphenol oxidase in conducting copolymers

Abstract

A copolymer of pyrrole with a new monomer (MBTA) containing an ester group derived from 3-thiophene acetic acid and (S)-(-)-2-methylbutanol was used as the matrix for immobilization of polyphenol oxidase. Enzyme electrodes were constructed by entrapment of enzyme in the conducting copolymer during the electrochemical polymerization of pyrrole. The performance of enzyme electrodes was optimized by examining the effects of pH and temperature on enzyme activity. The changes in the maximum reaction rate (V max) and Michaelis-Menten constant (K m) upon immobilization were investigated in addition to shelf-life and operational stability. By using these enzyme electrodes the total amount of phenolic compounds in red wines of Turkey was also analyzed.