Variables affecting the volatile compounds profile of commercial extra virgin olive oils produced in two cooperative mills

The volatile organic compound (VOC) content of a total of 88 extra virgin olive oil (EVOO) samples was investigated over two consecutive years in two cooperative mills. The oils were analysed by solid phase microextraction gas chromatography coupled with mass spectrometry (SPME-GC/MS) identifying 82 VOCs. PLS-DA models enabled good clustering emphasizing the importance of seasonality in the VOC profile. Many VOCs seem to keep the same behaviour between the two years independently from the mill. When both the year and the mill were used as response variables the model explained only 50% of the variance within the dataset. Therefore, the weight of the multifactorial “season” variable seems to be higher than the multifactorial variable “milling”. Some VOCs showed correlations with the fruit temperature before milling as well as with the health status of the olives. Valencene appeared to be positively correlated with the acidity of the oil samples. Therefore, the elevated valencene levels observed in some of the samples may be linked to the health status of the olives before milling. (E)-3-hexenyl acetate could be used as a distinctive marker of the oils produced with the autochthonous Tuscan cultivar Olivastra di Seggiano.