Characterization of castor seed oil extracted from the seed species native to Edo State, Nigeria

Abstract

Researchers have shown some concern over the use of castor seeds in the
preparation of local food condiment and the suitability of the oil quality
in diverse industrial applications. In Nigeria currently, there appears to be
little effort on the commercial cultivation and extraction of castor seed oil
to harness the economic potential inherent in the plant. This study seeks
to evaluate the physicochemical characteristics of castor seed oil keeping
in view the versatile applications of the oil in cosmetic, pharmaceutical,
paints, varnishes, lubricants and recently as renewable source. The oil
from castor seed obtained from Edo State, Nigeria was extracted using a
mechanically cold pressed method. The yield of the oil from the Castor
seed is 40%. The physical parameters of the seeds such as moisture
content, ash content and linear dimensions like length, width and
thickness were studied and found to be 0.32%, 6.44%, 12.02 mm, 8.20
mm and 5.06 mm, respectively. The physico-chemical analysis of the oil
showed viscosity of 0.413 cP @ 300C, pH of 5.50, saponification value
of 184.6 mg KOH g-1
, iodine value of 87.94gI2100g-1
, acid value of 5.92
mg KOH g-1
, specific gravity of 0.968 g/cm3
, refractive index of 1.477 @
27.40C, free fatty acid of 2.98% and peroxide value of 157.82 Meq/kg.
The extraction yield of 40% obtained makes the commercialization of the
seed in Nigeria feasible and profitable. The result of the analysis also
confirms the oil to be of good quality and can find application in food
industry as food additives as well as for industrial purposes.