Physicochemical properties and fatty acid composition of star fruit (Averrohoa carambola) seed oil

Abstract

To meet the increasing demands for oil, improvements are being made to produce unique and desirable oils, therefore increasing interest in newer sources of edible oils from natural sources. The physicochemical properties and fatty acid composition of Averrohoa carambola seed oil were determined. Physicochemical properties were determined using standard techniques and the fatty acid profile was obtained using Gas Chromatography Mass Spectroscopy (GC-MS). Soxhlet extraction (using petroleum ether) of the oil from sundried and crushed seeds of Averrohoa carambola gave light yellow oil with a yield of 28.45% oil per 100 g of the seeds. Other physicochemical properties of the oil determined were as follows; moisture content (7.2%), specific gravity (0.705), refractive index (1.421), acid value (0.68), free fatty acid (0.84), iodine value (140.50 g I₂ 100 g^-1), saponification value (190.0 mg KOH g^-1) and peroxide value (16.0 mEq kg^-1). The fatty acid profiles were revealed using Gas Chromatography Mass Spectroscopy (GC-MS). Linoleic (36.01%) and oleic (34.05%) were detected as the major fatty acid while palmitic (6.75%) and stearic acid (3.09%) were the saturated acid found in the oil. The compositions of the saturated fatty acids (SAFAs), monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs) were found to be 10.43, 34.44 and 51.98% respectively. Hence, the oil has a relatively high percentage of unsaturated fatty acid (86.42%). The outcome of this study showed that Averrohoa carambola seed oil may find wider industrial application and could be a nutriceutical resource or functional foods ingredient. Hence, the oil may be edible subject to toxicological test.

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Keywords: Characterization, levels, saturated, monounsaturated, polyunsaturated, standard techniques