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Properties of polyphenol oxidase in mango (Mangifera indica) kernel

1998; Wiley; Volume: 77; Issue: 4 Linguagem: Inglês

10.1002/(sici)1097-0010(199808)77

1097-0010

Sunday Salifu Arogba, O L Ajiboye, L A Ugboko, S Y Essienette, P O Afolabi,

Pineapple and bromelain studies

Polyphenol oxidase (PPO) 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 time to heat inactivate PPO decreased rapidly to < 10 min with increasing temperature of ⩾ 70°C at 50% activity. © 1998 SCI.