Echium seeds oil represents an excellent alternative as omega-3 fatty acids vegetal source, but its high polyunsaturated fatty acids proportion make it very susceptible to oxidative damage, leading to the formation of fishy odor during the seeds crushing. Our objective was to evaluate the influence of pro-oxidant enzymes on oxidative stability of echium oil, submitting the seeds to a thermal treatment, and characterize the volatile compounds formed during the oil extraction. Echium seeds were heated at 95°C for 15 min and some pro-oxidant enzymes activity was evaluated. Soybeans were applied as a control sample. Markers of oxidative stability and volatile compounds were identified and quantified. No activity of any lipoxygenase isoform (LOX-1, LOX-2 and LOX-3) was found in the echium seeds, while cytochrome c activity was observed, but it was not inactivated by the thermal treatment. In fact, the thermal treatment increased the hydroperoxide concentration in the echium oil, suggesting that different from soybean, echium oil was more susceptible to a non-enzymatic oxidation. Among the major volatile compounds found in the echium oil, (E)-2-octenal, 2,4-heptadienal, 3,5-octadien-3-one and hexanal were the main secondary compounds associated to echium seeds crushing odor. These results suggested that the oxidation of echium oil is not catalyzed by lipoxygenases and that the thermal treatment applied in this study is not recommended, because it increased the non-enzymatic oxidation of the echium oil. Other strategies should be evaluated aiming to prevent the oxidative damage of echium oil during the extraction and storage.
OXI-004: Effect of Thermal Treatment on Pro-oxidant Enzymes Inhibition and Volatile Compounds Profile during Oil Extraction from Echium Seeds
