Characterization of Chilean hazelnut (Gevuina avellana Mol) seed oil

The fatty acid composition, tocopherol and tocotrienol content, and oxidative stability of petroleum benzene-extracted Gevuina avellana Mol (Proteaceae) seed oil were determined. Positional isomers of monounsaturated fatty acids were elucidated by gas chromatography-electron impact mass spectrometry after 2-alkenyl-4,4-dimethyloxazoline derivatization. This stable oil (Rancimat induction period at 110 degrees C: 20 h) is composed of more than 85% monounsaturated fatty acids and about equal amounts (6%) of saturated and polyunsaturated (principally linoleic) fatty acids. Unusual positional isomers of monounsaturated fatty acids, i.e., C-16:1 Delta(11), C-18:1 Delta(12), C-20:1 Delta(11), C-20:1 Delta(15), C-22:1 Delta(17), and presumably C-22:1 Delta(19) were identified. The C-18:1 Delta(12) and C-22:1 Delta(19) fatty acids are described for the first time in G. avellana seed oil. While only minute quantities of alpha-, gamma-tocopherols and beta-, gamma- and delta-tocotrienols were found, the oil contained a substantial amount of a-tocotrienol (130 mg/kg). The potential nutritional value of G. avellana seed oil is discussed on the basis of its composition.