Comparative Chemical Evaluation of Three Species of Melon (Cucumis melo, Cucurbita moschata and Cucumeropsis mannii) Seeds

Abstract

Aim: This study evaluates the nutritional composition of three species of melon seeds (Cucumeropsis mannii, Cucumis melo, and Cucurbita moschata). The seeds were obtained from Nasarawa State, Nigeria. Methodology: Phytochemical constituents and proximate composition was determined by the method of Association of Official Analytical Chemists method (AOAC). Vitamins, amino acids and minerals were determined by standard methods. Oils were extracted from the samples using soxhlet apparatus with n-hexane. Results: The result of phytochemical analysis revealed the presence of phenol, alkaloids, terpenes, triterpenes, cardiac glycoside, sterols, terpenoids and tannins in the three species. The proximate composition revealed that crude fat is high in all the samples with C. moschata having the highest (41.23%) while C. mannii have the highest crude protein (26.31%). The result also reveals that all the samples have low carbohydrate (11%, 14% &13%) for C. mannii, C. melo and C. moschata respectively. The result of mineral composition reveals that potassium is high in all the samples with C. moschata having the highest (84.62 mg/100g) while Cadmium is the lowest (0.06mg/100g). The varieties also contain β-carotene, α-tocopherol and Ascorbic acid where β-carotene is the most abundant in the three varieties. The amino acid composition revealed leucine, alanine, phenylalanine, arginine, glutamic acid serine and aspartic acid to be the highest in all the samples. The percentage oil yield from the seeds were 32.90%, 31.38%, and 37.28% for C. mannii, C. melo and C. moschata respectively. The physicochemical properties of the oil obtained revealed acid value (mgKOH/g) in the range of 0.38-0.53. Saponification value (mg/KOH/g) 152.5-168.3, Iodine value (g/I2/100g) 92.7-119.5 free fatty acid (%Oleic) 2.34-3.66. Peroxide value (meqKOH/g) 4.56-6.38 and the pH in the range of 6.09-6.18 for C. mannii, C. melo and C. moschata respectively. Conclusion: The three melon seeds species contain almost similar nutritional composition. This justified the use of the melon seeds for industrial, food, medicinal and cosmetic purposes.