Optimization and determination of polyphenol oxidase and peroxidase activities in hot pepper (Capsicum annuum L.) pericarb

The activities of polyphenol oxidase (PPO) and peroxidase (POD) in hot pepper (Capsicum annuumL.) pericarp were evaluated using spectrophotometric method. The enzymes were extracted from the pepper pericarp 5 g with 20 mL of 0.1 M phosphate buffer solution pH 7. PPO and POD activities were determined using catechol and guaiacol as a substrate, respectively. The effects of the amounts of enzyme extract, substrate concentration, hydrogen peroxide concentration (only for POD), pH and temperature were investigated. The PPO activity was linearly increased with an increasing the amount of the enzyme extract between 20 and 200 μL. While the POD activity was also found in the same manner between 25 and 100 μL. The highest activity of PPO was obtained when using catechol concentration of 33 mM. That of POD was maximal optimized with 18 mM guaiacol and 4.9 mM H2O2. The optimum temperatures were 30°C for PPO and 40°C for POD. These optimum conditions were used to determine both enzyme activities in some varieties of hot pepper samples.