A system to control the atmosphere in the headspace of the malaxation machine to improve the fatty acid composition of extra virgin olive oils

In recent years, oxygen content regulation during malaxation has been noted as a process parameter. As concluded by many studies, the presence of oxygen during malaxation has a key role in for improving the quality of Extra Virgin Olive Oil (EVOO) in terms of volatile and phenolic components. There are, however, very few studies of the influence of oxygen in the malaxation machine headspace on the fatty acid composition of Extra Virgin Olive Oil (EVOO). The aim of this study is to evaluate the influence of oxygen in the malaxation machine headspace on Nocellara del Belice EVOO fatty acids. During of the malaxation process, the atmosphere inside the malaxation machine was modified by blowing pure oxygen from cylinders at specific stages of the process (i.e. 15, 25, and 35 minutes after the start of malaxation), using a system which ensures the automatic and continuous maintenance of a known amount of oxygen into the headspace at a given moment throughout the malaxation process. The results show that the amount of saturated and unsaturated fatty acids present in EVOO depends specifically on the timepoint of the malaxation process when oxygen is blown into the head space of the machine and much less on the amount of oxygen. The study confirms that monitoring and controlling the atmosphere inside the malaxation machine is necessary to obtain high quality EVOO with strong nutraceutical properties.