Development of a Simplified System for the Continuous PEF Treatment of Olives Paste

Abstract

The olive oil extraction is a complex process that requires several machines arranged in series until the plant is built. Currently, the extraction process does not allow the totality of the oil present in the olives to be extracted, unfortunately a significant amount of the product is lost in the by-products and waste. Recently the pulsed electric fields (PEF) applied to the process have given positive effects by increasing the percentage of oil extracted compared to the traditional plant configuration. In order to allow a greater diffusion of this technology in the mill, a simplified PEF plant it has been developed specifically for small oil extraction plants and an experimental test program has been developed to verify the effectiveness of the technology. A comparative experimental tests plant was carried out using two different varieties of olives (Frantoio and Leccino) treated at two different specific energies (4.0 and 5.0 kJ kg-1), the amount of olive oil lost in the pomace and extractability was found. The results showed that the treatment of the olive pastes in the pre-malaxation (5.0 kJ kg-1) led to significantly increased oil extractability compared to the control by about 4% (absolute value) for the Frantoio variety, and by about 3 % (absolute value) for the Leccino variety, while reducing the percentage of oil lost in the pomace. Further studies on the better adjustment of the operating parameters of the PEF system seem to be needed.