Automated control system for modified atmosphere in malaxer during olive oil extraction

The malaxation phase is reported in literature as one of the most important stages in extra virgin olive oil extraction, because it determines the balance between the quality and quantity of oil extracted. Numerous studies have shown that time and temperature of malaxation and amount of oxygen during the malaxation process influence the quality and quantity of extracted oil. In order to provide a tool useful in this research field, the authors have developed a study to design and build a prototype malaxer machine equipped with sophisticate apparatus (sensors and equipments) able to monitor and control the fundamental malaxing parameters. The goal of this research has been to integrate in a single prototype different tools and make it able to be working in the industrial plant. The efforts of the authors in this direction are justified by the belief that specific phenomena can be better explained when the research has been carried out in the industrial scale-up. The system consisted of the oxygen probes installed in the headspace and in the olive paste, a micro-oxygenator for infusion of oxygen in paste, never studied before, a head space nitrogen infusion system equipped to over-pressure valves and a torquemeter able to read a torque value in real time. The integrated system used on a prototype malaxer successfully passed the functionality test. The research demonstrated that this system makes it possible to vary the oxygen amount in the malaxer headspace as well as in the olive paste. The automated control system is definitely a useful tool for future research in the olive oil extraction process.