Compositional Studies of Rattle Box (Crotalaria retusa L.) Seeds Found in Nasarawa State, Nigeria

Abstract

The rattle box (Crotalaria retusa L.) is a lesser known plant grown wild in Nigerian soil. Studies were conducted on its seed flour and oils to determine their suitability, using standard analytical techniques. The result of mineral composition revealed that magnesium was the most abundant mineral (50.82 mg/100 g) while the least was arsenic (0.03 mg/100 g). Lead, cadmium and chromium were not at detecting limit of AAS. The most concentrated fatty acids were stearic acid (11.02%) < oleic acid (15.50%) < linoleic acid (57.54%). Caprylic, margaric, capric, lauric, myristic, arachidonic, erucic and lignoceric acids were all determined but not detected. Unsaturated fatty acids predominated in all the samples with only linoleic (57.54%) available as essential fatty acid. The results of physicochemical parameters of the seed oils determined were: Colour (yellow), acid value (1.10 mg KOH/g), iodine value (46.34 g/100 g), saponification (161.28 mg KOH/g), peroxide value (5.26 meq/kg), specific gravity at 25°C (0.88), kinetic viscosity at 40°C (4.91), unsaponifiable matter (1.92%) and flash point (231.00). The results showed that Crotalaria retusa seed oils may not be used as edible oils due to their instability as frying oils but may be useful industrially for the manufacture of products such as paints and shampoos.