Characterization of the lipoxygenases in some olive cultivars and determination of their role in volatile compounds formation

Enzymatic extracts from olive pulp (Olea europea L.) were used to characterize lipoxygenase (LOX)activity in order to determine its role in the biogenesis of the volatile compounds that influence thearoma of extra virgin olive oil. The LOX activity was tested spectrophotometrically at an optimal pHof 6.0 in three olive cultivars, Ascolana Tenera, Kalamata, and FS17. The trend of the LOX activitywas determined as a function of pH and temperature; the kinetic constants of the enzyme were alsodetermined. The highest LOX activity was observed in the FS17 fruit, which had the highestconcentrations of C 5 and C 6 compounds (aldehydes, alcohols, and ketones), followed by Kalamataand Ascolana T., respectively. Given the direct relationship between enzymatic activity and the quantityof aromas measured in the fruit, it is hypothesized that olive LOX is involved in the formation of C5and C 6 volatile compounds. To study the mechanism of the movement of the aromas from the fruitto the oil, which was obtained by simple mechanical extraction, the headspace of the oil for eachcultivar was analyzed as well as the aromatic composition in order to compare it with the aromas ofthe fruit