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.