Variations in seed traits of castor (Ricinus communis) accessions collected from Enugu state, Nigeria

Abstract

Four accessions (Accessions 1, 2, 3 and 4) of castor (Ricinus communis) were grown in Botanical Garden of the University of Nigeria, Nsukka in the derived savanna of southeastern Nigeria for two cropping seasons (2013 and 2014) in a randomized complete block design. The seeds harvested from them were subjected to chemical analysis. A soxhlet extraction was used for the extraction of the oil, using hexane as solvent. The oil was recovered by simple distillation of the solvent. The residual oil obtained was investigated for physicochemical parameters and fatty acid composition. The results showed free fatty acid compositions of linoleic acid (0.5%), stearic acid (1.3%) and palmitic acid (1.5%). The results of oleic, linolenic and ricinoleic acids were also reported. The physicochemical analysis showed that castor seed and oil had saponification value of 182.9 mg/g, moisture content of 4.4%, acid value of 3.085 mg/g, viscosity of 110.41 cP, pH of 6.11, iodine value of 8.46 mg/g, specific gravity of 0.962 and refractive index of 1.477˚C. The proximate analysis showed that moisture content of castor seeds varied from 9.02 to 9.66% while crude oil varied from 22.9 to 27 g. The results obtained were discussed in relation to the use of castor seeds in the preparation of local food condiment and the suitability of the oil quality in diverse industrial applications.

Key words: castor plant, fatty acid, physicochemical, iodine value, derived savannah