This study was aimed at extracting and purifying T. catappa seed oil
with a view to investigating the effect of processing on the
composition and antioxidant activity of the oil. Oil was extracted from
the dried and roasted T. catappa seed and subjected to degumming and
bleaching. The different processed oils were analysed for their fatty
acid, phytosterols, and fat soluble vitamins composition. Antioxidant
properties of the oils were also determined by measuring the
Diphenylpicrylhydrazyl (DPPH) radical scavenging activity and
inhibition of heat induced peroxidation. Roasting and processing caused
a reduction in acid value, increased peroxide value, but had no effect
on the iodine and saponification values of T. catappa oil. Palmitic
acid was the most abundant saturated fatty acid (42.466%) while oleic
acid was the most abundant unsaturated fatty acid (23.445%). Roasting
significantly reduced fatty acid concentration of the oil, and
bleaching of both unroasted and roasted oils increased the
concentration of fatty acids except linoleic acid. Gamma-sitosterol and
Beta-sitosterol were present in appreciable amounts only in the crude
oils. Roasting increased Vitamins A and D concentrations but
drastically reduced that of vitamin E. Degumming had no effect on the
fat soluble vitamins of T. catappa oil, but bleaching significantly
reduced the concentrations of all the vitamins. The DPPH radical
scavenging activity of the seed oil was between 26.93 ± 15.42% and
65.47 ± 31.59%. Refining increased the free radical scavenging
activity of the unroasted oil, but did not affect the antioxidant
activity of roasted oil. The capacity of the oil in preventing heat
induced peroxidation was comparable to that of Butylated hydroxytoluene
(BHT). Processing of the oil significantly increased its antioxidant
activity. Loss of vitamin E did not affect the antioxidant activity of
the oil. Thus, suggesting the presence of a heat stable antioxidant in
the oil. This study indicated T. catappa seed oil to be potential
pharmaceutical oil with good antioxidant characteristics