Characterization of Schinziophyton rautanenii (Manketti) nut oil from Namibia rich in conjugated fatty acids and tocopherol

The Schinziophyton rautanenii tree is an important food source for many communities of the African continent. Oil extracted from the Manketti nut is of great economic value, due to its unique composition and properties. In this study, the physical and chemical characteristics of the oil obtained from three extraction methods – cold pressed, traditional and Soxhlet extraction – were investigated and compared. Oil yield of the nut was found to be 42.6 ± 0.84%. Good quality characteristics, including saponification values (184–189 mg KOH/g), iodine values (120–131 g/100 g), acid values (0.959–2.44 mg KOH/g) and peroxide values (1.80–3.98 meqO2/kg) were found for the Manketti nut oil. The total tocopherol content was in the range of 144–206 mg/100 g of oil, with γ-tocopherol as the dominant tocopherol. The oil was rich in conjugated fatty acids, α-eleostearic (9Z,11E,13E-octadecatrienoic acid) (24–36%) and linoleic acid (9Z,12Z-octadeca-9,12-dienoic acid) (31–32%), making it a potential candidate in the nutraceutical and cosmetics industry.