Fatty acids and sterol composition of 'Empeltre' virgin oil in Ebro Valley and Balearic Islands

‘Empeltre’ clonal selection was carried out in Spanish NE since 1998 until 2002, within 79,000 ha along South Aragon, Catalonia, North Valencia, La Rioja, Navarra and Balearic Islands. After discarding trees which were different from ‘Empeltre’, 69 clones from this cultivar were selected and studied in situ during four years in order to compare virgin oil characteristics for ‘Empeltre’ cultivar within its original growing area. Environmental effects on fruit and olive oil composition were studied for five years. Results show significant differences related to original area for fatty acid composition explaining up to 72% of total variability, without any significant interaction between area and year. On the other hand, fruit characteristics and sterols composition show a significant area×year interaction. Mean values of the growing areas are reported. Discriminant analyses show a certain specificity level for fatty acids and sterols composition, as well as for fruit characteristics, related to growing area. Cluster analysis shows that South Aragon, North Valencia and Navarra have a similar fatty acid composition, while La Rioja (whit more ripe fruits), Balearic Islands (lower latitude and clearly different climate) and Catalonia belong to different clusters each one. Concerning sterols composition, South Aragon and North Valencia belong to the same cluster, then Navarra and La Rioja, and Balearic islands and Catalonia performs a third group. Canonical correlation analysis shows some interesting relations between fruit characteristics and fatty acids and sterols composition, suggesting that cultural practices and climatic factors that affect fruit development and ripening also promotes oil variations. In fact, larger fruits and those with a high flesh to pit ratio are usually richer in linoleic acid and poorer in oleic acid; in addition, fruits with a lower ripening index are usually richer in palmitic acid. Sigmasterol and campesterol seem higher when growing conditions increase fruit water content, while the same conditions produce oils lower in β-sitosterol and Δ7-avenasterol, although mill processing factors could be related by specific partition coefficients of these compounds. These results show certain variability within ‘Empeltre’ virgin oil characteristics that can be explained by environmental conditions that can modify fruit development and ripening.