Polyphenol Oxidase and Peroxidase in Luffa cylindrica

Factors affecting the properties of polyphenol oxidase (PPO) and peroxidase (POD) in luffa (Luffa cylindrica) were studied for information relating to enzymatic browning of the vegetable. The temperature, time duration, pH, and concentrations of the substrates, i.e., catechol for PPO activity and guaiacol for POD activity determinations, applied for the reaction as well as the wavelength used for the spectrophotometric color measurements were analyzed. The results indicated that (1) the optimum reaction system for PPO activity determination required the applications of wavelength at 408 nm for the spectrophotometry, a temperature at 35, a pH of 6.0, and an enzyme dosage of 0.15 mL with 0.056 moL·L^-1 catechol; and, (2) the optimum reaction system for POD, wavelength at 410 nm, a temperature at 40, a pH of 5.5, an enzyme dosage of 0.1 mL with 0.067 moL·L^-1 guaiacol.