Abstract

Rubber seeds from the rubber tree (Hevea brasiliensis) are in abundance in Nigeria from which non-edible oil could be obtained. However, the seeds are wasted in the rubber plantations annually even though the extractable oil has potential technical applications. If the full potentials of the oil are to be realized, there is need to have a data base information on the oil extraction process and its properties. Rubber seeds were collected from different rubber clones and extracted first by n-hexane to determine the yield characteristics. Second, the seeds were extracted by a hydraulic press at varied operating conditions: pressure range (5-8MPa), temperatures, 40-90^°C; and moisture content, 7-16 %. The effect of particle size and other operating variables on oil yield were studied. The physico-chemical properties of the extracted oil were evaluated. It was found that the percentage oil yield from the seeds of the rubber clone NIG800 at 45.03% was higher than the yield from other clones; GTI (40.21%) and RRIM 707 (38.42%) when the particle size of 1.16mm was used. Oil yield increased with increase in temperature and pressure. Maximum oil yield was obtained during mechanical pressing at a moisture content of 10% (wt), temperature of 70⁰C and pressure of 8MPa. The physicochemical characteristics of the oil showed high incidence of free fatty acid (FFA) of 37.96% (wt) and the high iodine value (IV) of 142.45 is indicative of the presence of high unsaturation.  Rubber seed oil could therefore serve as semi-drying oil used in ingredients for surface coating and in the formulation of products where the presence of unsaturation is important.

Key words: Rubber seed oil, extraction, particle size, temperature, moisture content.