INFLUENCE OF WATER ADDITION ON THE PERFORMANCE OF THE TWO-WAY OLIVE PASTE DECANTERS
A close inverse correlation has been observed among olive fruit and cake humidity, which go together, and dry olive cake oil content when using the two-way decanter recently introduced in the paste centrifugation oil extraction system. Therefore three trials were carried out at the end of the 1992–93 season to determine: a) whether the increase in humidity brought about by water addition to the olive paste to be injected to the decanter could allow for producing olive cakes with smaller oil content, and b) the best site for adding that water, to the mixer or directly to the decanter. Water addition at rates of around 10% to 30% of the fruit weight to be milled were compared to the non-addition used in this new olive oil extraction method and vegetation water was not produced in neither one. A Pieralisi decanter and 'Picual' olive fruit of 38% humidity were used. Analytical determinations concerned the olive oils (free acidity, k270 and k225, peroxide index, AOM stability and organoleptic characterization) and olive cakes (humidity and oil content). Main results were as follows: 1) the oil content (refered to dry matter) of the olive cake produced by this two-way decanter diminished by adding a certain amount of water to the olive paste; 2) the addition of that water was more efficient when injected directly to the decanter; 3) under the working conditions stated above the addition of water at a rate higher than 10%–15% of the fruit weight did not significantly diminish the dry olive cake oil content, and 4) no difference in olive oil quality was observed as a consequence of the different treatments.
Hermoso-Fernández, M., Uceda-Ojeda, M. and González-Delgado, J. (1994). INFLUENCE OF WATER ADDITION ON THE PERFORMANCE OF THE TWO-WAY OLIVE PASTE DECANTERS. Acta Hortic. 356, 341-343