A preliminary evaluation of antioxidant compounds, reducing potential, and radical scavenging of pawpaw (Asimina tribloba) fruit pulp from different stages of ripeness

This study reports preliminary findings for total phenolics, flavonoids, ascorbic acid, reducing potential, and radical scavenging of pawpaw pulp extracts from underripe, ripe, and overripe fruits. Total phenolics were affected by ripeness {underripe = ripe > overripe}, as were flavonoids (ripe < underripe < overripe). Reducing potential and radical scavenging were highest in ripe pulp and lowest in overripe pulp. Total phenolics were positively correlated with reducing potential and radical scavenging. Storing pawpaws at 4 °C for 7 d prior to methanol extraction affected total phenolic levels, ascorbic acid, and flavonoids, but had no effect on reducing potential or radical scavenging. Cooking pawpaws prior to extraction did not decrease the reducing capacity or radical scavenging. Storing pawpaw pulp extracts at −18 °C for 300 d increased reducing potential and radical scavenging. Storing pulp at −18 °C for 300 d before extraction caused a fourfold increase in total phenolics and flavonoids. These results indicate that pawpaw pulp from varying ripeness levels is a potential source of natural phenolic and flavonoid antioxidants that could lead to the development of value-added products from pawpaw.