Physical and Nutrient Characterisation of Raw and Processed Castor (Ricinus communis L.) Seeds in Nigeria

Castor bean (Ricinus communis L.) is an oilseed shrub of significant economic importance because of its several potential in industry and medicine. Castor seeds from four different locations in Nigeria were sampled and investigated for physical and chemical properties. The seeds size ranged from 0.08-0.9 g by weight and 0.8-1.9 cm by height. Since size is a continuous variation, the seeds were categorized into the small seeded variety (SSV) and the large seeded variety (LSY). More time and energy were expended in dehulling the SSV beside a considerable amount of kernel that were lost to the hull during processing. A tonne of castor seed generated about 53% of kernel for LSV compared to 49% kernel in SSV indicating a higher waste stream for SSV. The fibrous seed coat of 25% was obtained in LSV compared to 31% in SSV. The oil content ranged from 35- 37% with higher oil yield in SSV. The energy values and the protein content showed numerical differences in the two seed types. Crude protein content of 26.7% and 24.6% and crude fat of 47.3% and 49.4% and gross energy values of 6.59 kcal/g and 6.89kcal/g were obtained for LSV and SSV respectively. The anti nutritional factors measured revealed that the lectin component of 4.7HU mg/ml obtained for LSV and 3.1HUmg/ml obtained for SSV was lower in LSV because more of the material was required to produce positive agglutination. Values of O.41% and 0.48% phytate and 0.94% and 0.79% oxalate were obtained in LSV and SSV respectively. Different processing methods were attempted on the seed meal samples to neutralize the antinutrients present in them. Lectin were better inactivated with extraction with lye water, pH 9.5 and moist heating at 100°C for 20 min. Phytate levels were slightly decreased by fermentation for 3-day. Handling and nutrient profile favoured LSV over SSV and may have higher preference in livestock feeding system when treated with lye.