Changes in Olive Paste Composition During Decanter Feeding and Effects on Oil Yield

In olive oil production, olive paste is fed into a decanter in order to separate the oil from solids. The decanter is usually fed by a mohno or lobe pump. In this study, we analyze the composition of olive paste and pomace at the beginning, middle, and end of decanter feeding. The results show a change in paste composition with the two types of pumps. In both cases, olive paste contains a higher percentage of water and oil at the beginning of decanter feeding than at the end. This phenomenon is probably related to the different viscosity of the three components in the system. Furthermore, as the level for the recovery of olive oil is fixed, the change in the solid/liquid ratio causes product loss. This loss is demonstrated and quantified through the measurement of pomace oil content. Practical Applications: The paper quantifies the effect of the olive paste transport from malaxers to decanter on the olive oil yield. The transport causes a change in the relative composition among oil, water, and solids. The decanter centrifuge is not able to separate efficiently paste with different compositions. This causes marked product losses. The presented data could lead to the development of a control system able to limit the losses. In this study the ratio of solids, water and oil in the olive paste at the beginning, middle, and end of decanter feeding are tested. Change in paste composition with the two types of pumps. Olive paste contains a higher percentage of water and oil at the beginning of decanter feeding than at the end. The level for the recovery of oil is fixed and the change in the ratio causes product loss that is quantified through the measurement of pomace oil content