Olive and hazelnut oils: A study by high-field H-1 NMR and gas chromatography

High-field Nuclear Magnetic Resonance (NMR) and Gas Chromatography (GC) wer e used to analyse hazelnut and olive oils in order to evaluate the possibil ity of detecting hazelnut oil present in adulterated olive oil samples. The fatty acid composition of hazelnut oil was carefully determined and compar ed with the fatty acid composition of extra virgin olive oil. Linolenic aci d content and volatile aldehydes present only in non deodorized hazelnut oi ls were easily detected with NMR. If the content of linolenic acid was lowe r than 0.5% or if anomalous aldehydes were present, a full gas chromatograp hic analysis was performed. Different olive-hazelnut oil mixtures were prep ared and analysed by gas chromatography. Linear Discriminant Analysis (LDA) was used to analyse the GC results.