Effect of centrifugal force (G) on stability of natural emulsions (water/oil) present in fresh virgin olive oils

Abstract

Fresh virgin olive oils (VOOs) just obtained has a cloudy appearance, due to the presence of emulsified water and solid dispersed particles. The stability of these emulsions mainly depends on the water droplet size distribution and the presence of natural emulsifying agents in the oils. In this work, the effect of centrifugation force and time on fresh unfiltered VOOs from the horizontal decanter centrifuge (HDC) and vertical centrifuge separator (VCS) has been studied. The turbidity, moisture, insoluble impurities and phenol content of the oils were analyzed. The increasing of centrifugation force and time decrease the parameters studied of the unfiltered VOOs studied. The VCS oils showed a higher stability of the emulsion, since presented slightly higher values of the parameters studied after application the different centrifugation treatments. Fresh VOOs obtained in the mills can be considered metastable natural emulsions difficult to break with the current centrifugation systems of the olive extraction process.