A comparative study on antioxidant properties, proximate and mineral compositions of the peel and pulp of ripe Annona muricata (L.) fruit

The leaves, seeds and roots of Annona muricata (L.) (soursop) have been studied for pharmaceutical purposes with little attention paid to the study of the pulp and peel of its fruit. This study was therefore conducted to compare the antioxidant properties, phytocontituents, proximate and mineral compositions of the peel and pulp of ripe A. muricata fruit. The percentage protein, ash and fibre contents were higher in the peel while percentage fat, moisture, carbohydrate contents and total gross energy were higher in the pulp than the peel. The K/ Na ratio of the peel and pulp were higher than 1.0 recommended. The antioxidant potentials measured by ferric reducing antioxidant power (FRAP), 1,1-diphenyl-2-picrylhydrazyl (DPPH), Fe2+ chelation and hydroxyl radical scavenging ability tests in soursop peel were significantly higher than in the pulp. The peel also showed the strongest inhibition of lipid peroxidation. Furthermore, the result revealed the highest phenolic, flavonoid and vitamin C contents in the soursop peel. Free radical scavenging potentials of the extracts were found to be proportional to their respective phenolic and flavonoid contents. The results of our present study indicate that soursop peel exhibited significantly higher mineral composition, proximate composition, antioxidant activity and phytoconstituents compared to the pulp and thus, being an agrowaste, can be explored as a viable source of natural antioxidants for the functional food and pharmaceutical applications