Microwave and megasonics combined technology for a continuous olive oil process with enhanced extractability

The malaxation step is a lengthy batch operation in the traditional olive oil extraction, consisting of kneading and shearing the olive paste. This study evaluated the ability of microwave heating to substitute the malaxation process without and with megasonic treatment of the paste. An industrial microwave and megasonic prototype was installed in a commercial olive oil plant. Four processing scenarios were evaluated. The average olive oil yield obtained by using microwaves, showed no significant difference with respect to the traditional malaxation. Yields showed increased extractability after exposing the microwave-treated and malaxed paste to a megasonic field by 1.98% and 2.25%, respectively. The oil content in the pomace verified the yield trends observed. Both microwave and megasonic treatments reduced the consistency of the paste. This study confirms the ability of microwave-treated to substitute the malaxation and for the first time demonstrates the ability of a subsequent megasonic intervention to increase yields. Industrial relevance The results of this paper demonstrated the ability of microwave treatment to substitute the traditional malaxation process and for the first time demonstrates the ability of a subsequent megasonic treatment to further aid the process towards increased yields. The study carried out in an oil extraction industrial plant confirms that it is possible to insert microwave and megasonic prototypes in an industrial line to overcome the batch nature of the malaxation process, thereby producing a continuous process. The combination of microwave and megasonic equipment into a modular unit could represent a new frontier for olive paste conditioning in olive oil extraction plants. This work revisits the layout of the extraction olive oil line to reduce the plant's complexity.