Nineteen cultivars of hazelnuts (Corylus avellana L.) collected during the 2001 crop, from Vila Real, Portugal, were analysed for chemical composition, including
moisture, total oil content, crude protein, ash, carbohydrates
and nutritional value. Fat was the predominant
component, ranging from 59.3 to 69.0%. Total oil was extracted
and analysed for fatty acid and sterol compositions
and oxidative stability. Fatty acid and sterol compositions
were determined by Gas–Liquid Chromatography coupled
to a Flame Ionisation Detector (GLC/FID). Monounsaturated
fatty acids, particularly oleic acid, were predominant
(78.7–84.6%). Total phytosterol content ranged from 133.8
to 263.0 mg/100 g of oil. Among the nine sterols identified and quantified, β-sitosterol was the major one with
a mean percentage of 83.6%, while Δ5-avenasterol and
campesterol were the second and the third components of
the group with mean values of 6.1 and 5.8%, respectively.
Since hazelnut oil can be used in olive oil adulteration,
the values obtained were compared with published mean
values of olive oils from different geographical origins.
