Evaluation Of Peroxidase (POD) Activity Of Mango (Mangifera indica) Fruit Pulp At Different Level Of Ripeness

Abstract

Crude peroxidase (POD) was extracted from unripe (UR), about to ripe (AR) and ripe (RP) mango (Mangifera indica) fruit pulp using a spectrophotometer and pyrogallol as the substrate. Peroxidase activity, the effect of pH and temperature on peroxidase activity and the kinetics of the fruit pulps were studied. The result showed that peroxidase activity was present in all the mango samples investigated. Peroxidase activity increased as the fruit pulp ripened and was highest in the ripe (RP) sample. Peroxidase enzyme exhibited maximum activity at pH 5.5, 6.0 and 6.5 for UR, AR and RP samples respectively. All the samples showed high enzyme activity at temperatures 10 0C to 20 0C. At 70 0C, 50 % enzyme activity was lost in AR sample while 60 % activity was lost in UR and AR samples. The enzyme in all the samples were completely inactivated when incubated at 90 0C. The Michaelis- Menten constant (km) for AR, UR and RP samples were 0.283 M, 0.463 M and 0.477 M respectively with a maximum enzyme velocity (Vmax) of 0.020, 0.028 and 0.030 enzyme unitts/g fruit pulp for UR, AR and RP samples respectively. The value of km suggests that POD from unripe (UR), about to ripe (AR) and ripe (RP) Mangifera indica fruit pulp can be isolated, purified, characterized and quantitatively made available for biotechnological