Development of a Prototype for Extra-Virgin Olive Oil Storage with Online Control of Injected Nitrogen

摘要

The conservation of oil is a very complex operation because, to maintain the quality level over time, it is necessary to take precautions to avoid increased acidity and the onset of rancidity caused by oxidation, as well as problems related to the anaerobic fermentation of suspended matter in the oil or deposited on the bottom of the storage vessels. This article describes the development of a prototype integrated olive oil storage system. The storage system consists of a nitrogen gas generator, three stainless steel tanks, and a feedback controller for nitrogen concentration and tank temperature. In the first experiment, three tanks were used to test the functionality of the system. The experimental design was based on the creation of a different modified atmosphere in the headspace of each tank using the nitrogen gas generator and feedback controller. In the second experiment, four tanks were used to validate the functionality of the prototype system using a different type of extra-virgin olive oil. The results of this research show that the prototype performed well in terms of its ability to detect and adjust the atmosphere of the tank headspace. In the first experiment, the oxygen percentage in the headspace of the three tanks remained between0.7% and 0.9%. Chemical analyses of acidity, total phenol content, and peroxide index showed that the controlled headspace made it possible to maintain acidity levels within the range of 0.30% to 0.37%, total phenol content in the range of 247 to 252 ppm (gallic acid equivalent), and peroxide index values in the range of 8.80 to 9.70 meq 02 per kg of oil during the experiment. The proposed prototype provided effective control and regulation of the oxygen concentration in the headspace of the tanks andcan help maintain the chemical characteristics of extra-virgin olive oil over time. The second experiment confirmed that the prototype storage system was able to maintain the chemical characteristics of the stored extra-virgin olive oil.