Abstract

Amália Uamusse and Samuel Owusu Yeboah

The physicochemical properties and fatty acid composition of the edible aril oils from four variants of Trichilia emetica Vahl (Meliaceae), obtained by Soxhlet extraction, were determined. The oil yields ranged between 42.2 – 53.8% (w/w). Determination of the stability parameters, acid value (AV) and peroxide value (PV), indicated that all four oil samples were stable to hydrolytic and oxidative stress (AV = 0.88 – 1.02 mg KOH/g and PV = 2.02 - 2.62 mEq/kg). The refractive indices (RI = 1.466 – 1.467) and the iodine values (IV = 63.42 – 78.02 mEq/kg) indicated that the four oil samples were all moderately unsaturated, while the saponification values (SV = 183.71 – 189.03 mg KOH/g) indicated that the oil samples consisted mainly of medium length fatty acid chains. GC-MS determination of the fatty acid profiles (16:0 = 40.29 – 46.76%, 18:1 = 25.28 – 30.44%, 18:2 = 24.99 – 27.64%) confirmed the moderate unsaturation and showed that all four oil samples consisted mainly of C16 and C18 carbon chains. The GC-MS findings were closely corroborated by 1H-NMR determination of the fatty acid classes. The study showed that the characteristics of the oil from the seed arils from the four variants of T. emetica were all similar to each other and compared favourably with the properties of some well-known edible household oils such as palm oil and olive oil. Hence, the four variants are all equally suitable for further evaluation towards commercial exploitation of the fruit oil.