Assessment of Vitamins, Minerals and Phytochemical Variability in Watermelon (Citrullus lanatus) Varieties from South-West Nigeria

Background and Objective: Watermelon is a commonly consumed tropical fruit in developing countries including Nigeria. The pulp of the fruits is mainly consumed while the seeds and rinds are discarded, causing environmental pollution. This study investigated the nutritional composition of watermelon seeds and rinds for possible food or feed usage. Materials and Methods: Field experiments were conducted between August-November, 2016 in Ogbomoso to determine the variability of vitamins and minerals content among the pulp, seed and rind of four watermelon varieties (Sugar Baby, Kaolack, Grey Belle and Collos F1). At fruit maturity, six fruits per variety weighing 3 kg were randomly selected for vitamin (vitamin A, C and E) and mineral (calcium, magnesium, potassium, iron, zinc and copper) analyses. Results: The results of the experiment showed there are variations in the vitamins and mineral content of watermelon pulp, seed and rind. Kaolack pulp has the highest concentration of vitamin C (8.16 mg/100 g) while the seed and Collos F1 rind have the highest concentration of vitamin E (0.130 mg/100 g) and A (450.00 μg/100 g), respectively. Mineral content was higher in the seed and rind than in pulp. Collos F1 seed had the highest calcium content of 532.1 mg/100 g while Potassium content was found in larger quantities in Kaolack seed (1144.4 mg/100 g) while Kaolack rind had the highest Zinc (3.04 mg/100 g). Conclusion: The vitamins and minerals that are abundant in the rind and seed which are often discarded are good sources of vitamin and mineral elements that play various physiological functions in the human body. Also, the rind and seed can be used in animal feed.