Gene expression and enzyme kinetics of polyphenol oxidases in strawberry and their possible involvement in enzymatic browning reactions in strawberry nectar

Polyphenol oxidase (PPO), an enzyme responsible for the oxidation of a wide range of polyphenols in plants, is believed to play a major role in this browning effect. In this study, four recombinant PPOs were analyzed for their substrate specificity.

Additionally, gene expression levels of these PPOs were assessed in 10 cultivars of Fragaria × ananassa across five ripening stages. To investigate potential browning inhibitors, strawberry nectar was prepared with different additives: • Phloretin at concentrations of 30 and 60 µmol/L • Aubergine powder at a 1:1 w/v ratio • Clear apple juice as a substitute for water in the nectar formulation The dataset presented here includes raw data from the kinetic study (absorbance values).