Description of subject. In Democratic Republic of Congo, a wide range of plants, both domestic and wild, contains fat that can be valued in various areas of life. After extraction of the oil by pressure or by means of solvents, the meal contains minerals with a certain nutritional value. Thus, a study relating to this question was carried out.
Objectives. The objective of the research is to promote the valorization of oil cakes, by-products of unconventional oilseeds with a view to considering their use in the food ration.
Methods. The oil was extracted from ten unconventional oilseed species: Allophylus africanus (AA), Carapa procera (CP), Cannabis sativa (CS), Coula edulis (CE), Hura crepitans (HC), Monodora myristica (MM), Ongokea gore (OG), Moringa oleifera (MO), Pentadesma butyraceae (PB), Pentachletra eetveldeana (PE) using petroleum ether as solvent. The oil cakes obtained from the extraction of oil from these oil seeds were analyzed and their mineral composition was determined. The crude ash was obtained after calcining the grain powder in a muffle oven. The composition of major minerals (calcium, magnesium, potassium, phosphorus and sulfur) was determined by X-ray fluorescence spectrometry at CGEA/CERN-K.
Results. The results showed that the meal of Pentadesma butyraceae (PB) contained (per 100g of dry matter) the highest amount of Ca (849.80 mg). Carapa procera (CP) had the highest K content (925.22 mg). The oil cakes of the species Hura crepitans (HC) (59.75 mg), Ongokea gore (OG) (59.92 mg) and Moringa oleifera (MO) (57.26 mg) gave a higher phosphorus content than the others.
Conclusion. The analysis revealed the presence of five major mineral elements: Ca, Mg, K, P and S. All the oil cakes of the species under study have appreciable quantity of minerals and could be used as food supplements for both man only or for cattle.
Keywords : Oil cake, unconventional oilseeds, mineral elements, DRC.