Question

1.1   What would the effect of each reagent (control buffer; substrate buffer; citric acid and ascorbic acid) be on the browning process?                                                                                                                              (4)

Answer 1

 All the compounds reduced both the browning and the PPO process.the browning indexes produced strong correlations with the reagents activities. Ascorbic acid reduced the formed Quinone. Cysteine at a high concentration reacts with the Quinone to produces a colorless product in low concentration. Citric acid acts as a non-competitive inhibitor