Effects of Seasonal Weather Variability on Olive Oil Composition in Northern Italy

Composition and quality profiling of olive oils from two cultivars (‘Casaliva’ and ‘Leccino’) in seventeen olive groves were studied for four years (1998-2001) in “Garda Bresciano” area (western cost of lake Garda, northern Italy), in relation to seasonal weather fluctuation in term of air temperature and rainfall. Fruits from adult trees of average growth and yield were harvested individually in each orchard and the oil was extracted at fruit veraison. All oil samples were obtained by a laboratory oil mill within one day from picking. The olives were crushed, malaxed and oil was extracted by hydraulic press and separated by centrifugation. All oils were classified as “virgin”. Polyphenols, tocopherols and volatile compounds were analyzed. Total polyphenols, tocopherols and volatile compounds resulted negatively correlated to maturity index, whereas ‘Casaliva’ cultivar was positively correlated to heat summation during olive maturation (from August to October).