Unlocking the Nutritional Potential of Watermelon Seed Derivatives: A Comparative Analysis of Cake, Oil, and Powder

Background and Objective: Watermelon seed cake, a by-product of watermelon seed oil extraction, is a potentially valuable source of nutrients. However, its chemical composition and proximate analysis are not well documented. This study aims to investigate the proximate composition and chemical characteristics of watermelon seed cake, oil, and powder, to explore their potential applications in food, feed, and industrial sectors. Materials and Methods: Watermelon seed cake, oil, and powder were obtained from a local oil mil. Proximate analysis was performed using standard methods, and the chemical composition was analyzed. The watermelon seed passed several processes which including cleaning, drying, grinding, and particle sizing, to obtain the powder. The ash content was determined by incineration, fat content was assessed by the use of solvent extraction through the Soxhlet apparatus, protein content was quantified using the micro-Kjeldahl Method, and crude was measured by sequential digestion and ashing. Carbohydrate was calculated by difference. The oil was extracted using the Soxhlet technique, which is the common method for oil extraction. Results: Proximate analysis revealed that watermelon seed cake contained. 11.18% moisture content, 3.57% ash content, 18.9% crude fibre, 13.72% crude fat, 10.47% crude protein, 42.16% carbohydrate, and 89.35% dry matter. The oil contained specific gravity of 0.92 g/cm³, acid value of 3.5 mg KOH/g, peroxide value of 2.9 mg KOH/g, iodine value of 75.0 mg KOH/g, saponification value of 149.0 mg KOH/g, viscosity ( at 26.7°C) of 50.00 cP, refractive index of 1.45 while the powder contained moisture content 10.65%, ash content 5.1%, crude fibre 7.9%, crude fat 2.77%, crude protein 5.95%, carbohydrate 67.65% and dry matter 89.35% Conclusion: This study provides valuable information on the proximate analysis of watermelon seed cake, oil and powder. The results highlight the potential of watermelon seed cake, oil, and powder as a nutritious ingredient for food and feed applications, while underscoring the importance of sustainable utilization of these underutilized resources.