Characterization of Varietal Virgin Olive Oils from Mendoza by their Volatile Composition

FERNÁNDEZ MARÍA DE LOS ANGELES; ASSOF MARIELA; JOFRE VIVIANA; SILVA MARIA FERNANDA

San Juan

Simposio; VIIth INTERNATIONAL SYMPOSIUM ON OLIVE GROWING; 2012

The distinctive aroma of virgin olive oil is attributed to a large number of chemical compounds of different classes such as aldehydes, alcohols, esters, hydrocarbons, ketones, furans and other volatile compounds that are not yet identified. Some of the volatile compounds found in virgin olive oil are present in the intact tissue of the fruit, and others are formed during disruption of cell structure during the virgin olive oil production due to enzymatic reactions in the presence of oxygen. In fact, cultivar, geographic region, fruit maturity and processing methods influence the volatile composition of olive oil. The aim of this work was to study the effect of the cultivar (Arauco, Empeltre, Farga and Arbequina) on the concentrations of the volatile compounds in virgin olive oils. To avoid the influence of factors other than the cultivar, olive trees were cultivated under the same agronomic (i.e. fertilization, irrigation) and pedoclimatic conditions; olive fruits were picked at the same stage of ripeness, and their oils were extracted with the same processing system. A method involving headspace-solid phase micro-extraction (HS-SPME) and gas chromatography with mass spectrometry (GC–MS) detection was optimized to investigate the volatile composition of olive oils. Three SPME fibers were tested for extraction. Carboxen/polydimethylsiloxane (CAR/PDMS-75μm) fiber was the most efficient to trap volatile compounds. Optimization of the extraction conditions was carried out using multivariate methods, such as central composite design. Volatile fractions from oils of the analyzed cultivars consisted of a complex mixture of more than 30 compounds. Both quantitative and qualitative differences were found among cultivars.