A HIGH-FIELD H-1 NUCLEAR-MAGNETIC-RESONANCE STUDY OF THE MINOR COMPONENTS IN VIRGIN OLIVE OILS

High-field (600 MHz) nuclear magnetic resonance (NMR) spectroscopy was applied to the direct analysis of virgin olive oil. Minor components were studied to assess oil quality and genuineness. Unsaturated and sa turated aldehyde resonances, as well as those related to other volatil e compounds, were identified in the low-field region of the spectrum b y two-dimensional techniques. Unsaturated aldehydes can be related to the sensory quality of oils. Other unidentified peaks are due to volat ile components, because they disappear after nitrogen fluxing. The sta tistical analysis performed on the intensity of these peaks in several oil samples, obtained from different olive varieties, allows clusteri ng and identification of oils arising from the same olive variety. Dia cylglycerols, linolenic acid, other volatile components, water, acetic acid, phenols, and sterols can be detected simultaneously, suggesting a useful application of high-field NMR in the authentication and qual ity assessment of virgin olive oil.