Selected Under-exploited Plant Oils in Nigeria: A Correlative Study of their Properties

Abstract

This study examined the physicochemical properties of seven under-exploited plant oils in Nigeria,namely; Hevea brasiliensis seed oil (HBSO), Prunus dulcis seed oil (PDSO), Afzelia africana arilcap oil (AAACO), Jatropha curcas seed oil (JCSO), Sesamum indicum seed oil (SISO), Canariumschweinfurthii seed oil (CSSO) and Hura crepitans seed oil (HCSO). Characteristics such ascolour, percentage yield, specific gravity, freezing/melting point, acid value, free fatty acid, iodinevalue, and saponification value were investigated. The results showed that they have differentcolours and are liquid at room temperature. The percentage yield of the extracted oils varied from34 to 55.39%. The specific gravities which were observed to agree with what is obtainable in mostvegetable oils were in the range of 0.91 in PDSO to 0.948 in CSSO. The freezing/melting pointsshow that CSSO (8.89 °C), AAACO (6.39 ºC) and JCSO (3.18 ºC) have greater amounts ofsaturated fatty acids than SISO (–6.21 ºC), HCSO (–15.34 ºC) and HBSO /PDSO (–18 ºC). Theacid values and free fatty acids of the oils were in the range of 2.13–17.49 mg KOH/g and 1.07–9.648%, respectively. The iodine values of HBSO, PDSO, JCSO, and SISO (104–128.9 mgiodine/100 g) and AAACO and CSSO (68–77 mg iodine/100 g) placed them in the semi-dryingand non-drying class, respectively. Their saponification values (137.2 to 210 mg KOH/g oil)suggest their possible applications in the soap industry. The results generally present a deductivejustification for the usage of the studied plant seed oils for some industrial and other applications. Keywords: Plant seed oils; physicochemical properties; potential applications;