Seasonal dynamics of oil accumulation and fatty acid composition in olive varieties in northwestern Argentina.

RONDANINI D.P.; CASTRO D.; SEARLES P.; ROUSSEAUX M. CECILIA

San Juan

Simposio; VII International Symposium on Olive Growing; 2012

International Society of Horticultural Science

Fatty acid composition of some virgin olive oils from warm valleys of NW Argentina frequently are not within the standard ranges indicated by the IOOC, even in olive varieties that meet standards in their zones of origin in the Mediterranean basin. The most common defects are low oleic, high palmitic, and high linoleic acid contents. In order to determine how such fatty acid values are achieved, the evolution of fatty acid composition was analyzed in six olive varieties growing in three warm valleys in La Rioja, NW Argentina. A general bi-linear model was fitted to each variety, and four contrasting patterns of oleic acid dynamics during ripening were observed: (1) a brief plateau followed by an early, sharp linear decrease (Arauco and Arbequina); (2) a long plateau followed by a late linear decrease of moderate slope (Barnea and Manzanilla); (3) a brief plateau followed by a slow linear decrease starts early (Frantoio); and (4) no decrease (Coratina). Three novel contrasting patterns of increase (Arbequina and Arauco), slight decrease (Barnea, Manzanilla and Frantoio) and strong reduction (Coratina) of palmitic acid have been also identified. Minimum temperature during oil synthesis period (ranging 16-21ºC) was negatively related to final oleic acid content. These findings bring a physiological description about how particular fatty acid composition is reached in virgin olive oils from varieties growing in warm valleys from NW Argentina, and how they can fail in their purity analysis, although they are effectively virgin olive oils obtained from fresh fruits of olive varieties.