Chemical content of the seeds and physico-chemical characteristic of the seed oils from Citrullus colocynthis, Coccinia grandis, Cucumis metuliferus and Cucumis prophetarum of Niger

Abstract

The aim of this study was to determine the chemical composition of the seeds of Citrullus colocynthis, Coccinia grandis, Cucumis metuliferus and Cucumis prophetarum belonging to the family of Cucurbitaceae. For each variety, the ash, protein, fat, calcium, copper, iron, phosphorus, magnesium, potassium, sodium and zinc were determined. The oils were characterized by the determination of the acid (IA), iodine (II), saponification (IS), refraction (IR) numbers as well as the fatty acids and anti-oxidants composition and the non-saponification percentage. Our results showed: 13.19-26.86 % protein content, 14.48-24.62 % fat content, and 2.00-4.46 % % ash content. Respectively the mineral matter was as follow calcium (246.90-569.47 mg/100 g); copper (5.10-5.79 mg/100 g); iron (10.95-15.57 mg/100 g); magnesium (209.83-289.07 mg/100 g); potassium (465.27-1205.12 mg/100 g); phosphorus (30.03-49.13 mg/100 g); sodium (11.89-16.67 mg/100 g) and zinc (1.05-2.92 mg/100 g). The physicochemical characterization of the oil revealed that: IA was within 2.90-6.31 mg of KOH/g, Is within 171.67-208.90 mg of KOH/g, II within 138.10-14674 g of iodine for 100 g of oils and IR within 1.4607-1.4620. The non-saponification percentage was within 1.07-3.39 % and the predominant fatty acids were palmitic acid (15.12-17.29 %), stearic acid (7.65-9.04 %), oleic acid (10.77 %-18.57 %) and linoleic acid (56.21-64.188 %). The study of the anti-oxidants fraction showed: 804-80 mg/kg α-tocopherol content, 83.14-619.37 mg/kg γ-tocopherol content and 0.05-0.23 mg/kg β-carotene content. © 2007 Chemical Society of Ethiopia.