Optimization of Peroxidase Activity of Turnip (Brassica rapa) Using Response Surface Methodology

The present study is focused on the determination of optimized activity conditions of peroxidase (POD) of turnip (Brassica rapa). The enzyme is extracted from turnip with 0.5M Na₂HPO₄ (pH7.0). Peroxidase activity is evaluated by monitoring the oxidation of guaiacol to tetraguaiacol in the presence of hydrogen peroxide (H₂O₂). Before the optimization of peroxidase activity from a turnip by response surface methodology (RSM), a preliminary step is conducted for each studied parameter (pH, temperature, and NaCl concentration). Further, RSM following Box-Behnken design is used in order to refine the optimization of the conditions. Response surface analysis showed that parameter values with the highest peroxidase activity are 5.9, 29.8°C, and 1.07M for pH, temperature, and NaCl, respectively. Under these experimental conditions, peroxidase activity is found to be 4027.25U/mg. The obtained experimental value agrees with that of the calculated one, indicating the pertinence of the developed model for the optimization of peroxidase activity.