Properties of polyphenol oxidase in mango (Mangifera indica) kernel.
Arogba S. S., Ajiboye O. L., Ugboko L. A., Essienette S. Y., Afolabi P. O.
Author Affiliation: Department of Food Technology, The Federal Polytechnic, PMB 1037, Idah, Kogi State, Nigeria.
Journal of the Science of Food and Agriculture 77 : 459-462
Abstract : Polyphenol oxidase (PPO) [catechol oxidase] activity of filtered extract of ground mango kernel suspension (400 g litre-1) was studied spectrophotometrically at 420 nm using catechol as substrate. The enzyme was most active at pH 6.0 and 25°C. Activity was reduced by 50% at pH values of 5.0 and 7.1, and also at temperatures of 14°C and 30°C. The calculated activation energy and the Michaelis constant (Km) were 21.4 kcal mol-1 °C-1 and 24.6 mM, respectively. The Vmax value was 2.14 units g-1 mango kernel. The heating time to inactivate PPO decreased rapidly to 10 min when temperature increased to ?70°C at 50% activity.