Comparative Study on the Nutritional and Antioxidant Components of Fruit Parts of Citrullus lanatus

Aim: Citrullus lanatus is a fruit widely consumed for its pulp though incompletely, as its other parts (seed and rind) are discarded and may possibly offer bioactive compounds involved in ameliorating certain disease conditions. Hence, this study aimed at comparatively investigating the nutritional composition and antioxidant properties of the seed, pulp and rind of C. lanatus so as to inform the inclusion of these different parts into the fare of the people.

Methodology: Standard analytical methods of Association of Official Analytical Chemists were used to determine proximate, phytochemical, vitamin, mineral and antioxidant aspects of the fruit parts. The results were analyzed using Student’s t-test at .05.

Results: The proximate analysis showed a high moisture value in the pulp (93.34 +/- .82) followed by the rind (77.11 +/- 3.44) and the seed (10.00 +/- .48). High crude protein and fiber contents were both noted in the seed followed by the rind and pulp. Mineral determinations revealed potassium to be abundant in the rind (452.31mg/kg) than the seed (305.7mg/kg) and the pulp (100.5mg/kg), followed by calcium occurring more in the rind (292.61mg/kg) than in the pulp (257.21mg/kg) and seed (227.45mg/kg) and then manganese being the least concentrated among the minerals. The investigated phytochemical principles revealed the highest concentration of cardiac glycosides in the seed (14.82 +/- .66) than the rind (1.95 +/- 0.80) and pulp (1.10 +/- 0.17), followed by saponins occurring most in the rind (12.05 +/- 3.91) than the seed (10.17 +/- 0.63) and pulp (.13 +/- .01). The seed had the highest DPPH scavenging activity followed by the rind and pulp respectively. The seed also showed a higher reducing power and lipid peroxidation capacities than the other fruit parts suggesting a potent property for antioxidant activity in the fruit parts of C. lanatus.

Conclusion: The findings imply that both seed and rind of C. lanatus can be good sources of nutritional, phytochemical and antioxidant components in addition to the pulp which is commonly consumed and these may be implicated in management of certain diseases with further evidential research.