FRUIT RIPENING STAGE EFFECT ON THE FATTY ACID PROFILE OF 'ARBEQUINA' AND 'PICUAL' OLIVES IN URUGUAY

Uruguay is one of the countries with favorable conditions for the development of olive tree culture. Olive oil is mainly composed by triglycerides, formed by different fatty acids which confer a main portion of its properties. Its acidic composition varies mainly with variety, local climatic conditions and fruit maturity degree. The objective of this work is to know the influence of fruit maturity stages on the fatty acid profile in the ‘Arbequina’ and ‘Picual’ varieties cultivated in Uruguay. According to skin and flesh color, fruits at six stages of maturity were used for extraction of lipids and percent fatty acid composition was determined through gas chromatography on methylated byproducts, palmitic, palmitoleic, estearic, oleic, linoleic and linolenic. Across different maturity stages and on ‘Arbequina’ and ‘Picual’ the C16:0 was constant and showed a value of 20 and 19.5% respectively, showing no significant changes. The C16:1 and C18:2 significantly increased from the M1 to the M6 stage in ‘Arbequina’ and ‘Picual’ (C16:1 increased from 1.9 to 3.3 and 1.5 to 2.2 respectively; C18:2 from 8.0 to 13.3 and 1.6 to 6.5% respectively). C18:1 and of C18:3 levels significantly decreased in oils originated from fruits with more advanced maturity (C18:1 varied from 67 to 60 and 74 to 70 respectively; C18:3 varied from 0.6 to 0.4 and 0.7 to 0.5%, respectively). With advancing maturity, C18:0 level decreased in ‘Arbequina’ (1.7 to 1.4%) and increased in ‘Picual’ (1.8 to 2.5%), both showing significant variations. With advancing maturity and on both varieties, ratios between monounsaturated and polyunsaturated fatty acids decreased, and the decrease was greater in ‘Picual’. Focusing on the potential oil quality, preliminary data emphasize the importance of understanding the effect of maturity stages as related to the development of olive harvest indexes.