Mild separation system for olive oil: quality evaluation and pilot plant design

Abstract

The entire process of olive oil extraction involves the breakage of olive fruits to obtain a paste, the kneading of the paste, a centrifugation, and a further cleaning, performed by a disc stack centrifuge, to separate the residual water. In this research, in order to evaluate the effect of final centrifugal separation on olive oil quality and to both define and design the settings of a innovative separation system, olive oil was separated off from water using an accelerated separation process, tested in comparison with a disc centrifuge. The laboratory plant used for the trials was constituted by a twin cylindrical separator equipped with 4 variable frequency inverters, in order to regulate the fluid flow rates in the plant. Oil samples were collected during the trials to evaluate the influence of the proposed innovative process on oil quality; measuring some parameters as free acidity, peroxides (PV), specific extinction coefficients K232 and K270, chlorophylls , carotenoids, total polyphenols (POL) and turbidity. Results showed statistically significant differences (p-values<0.05) in some parameters as POL, PV, and ultraviolet absorption K232 and K270.