Influence of the feed pipe position of an industrial scale two-phase decanter on extraction efficiency and chemical-sensory characteristics of virgin olive oil

BACKGROUND: Nowadays, olive oil extraction is basically achieved by means of two-phase decanters, which allow a reduction of water consumption and the leaching of phenolic compounds. Despite this, most of the working settings derive from studies carried out on three-phase decanters. Hence, the aim of the present studywas to assess the influence of two-phase decanter feed pipe position (FP) on the extraction efficiency and chemical-sensory characteristics of virgin olive oil. Three different positions were considered: at 825mm(FP1), 610mm(FP2) and 520mm(FP3) fromthe outlet of the oily phase. RESULTS: Position FP3 allowed the highest oil recovery (up to 10%), the lowest percentage of oil in the olive pomace and, in general, a regular trend in terms of oil extraction efficiency. However, the oily must that came out of the decanter was not completely clean in terms of residual content of solid sediment and water. The feeding position partially affected the profile of antioxidant compounds. CONCLUSION: In two-phase decanters, loading the olive paste close to the outlet of the oily phase is recommended to increase the extraction efficiency without jeopardizing the chemical-sensory characteristics of virgin olive oil.