OPTIMIZATION OF OLIVE PASTE EXPRESSION - MAXIMIZING YIELD BY CENTRAL COMPOSITE DESIGN APPROACH

This work shows results from an optimisation test of olive paste expre ssion. A factorial design was first used to evaluate the effect of the simultaneous variation of the following parameters on the extraction yield: pressure, compaction rate, cake thickness and solids content in the olive paste. It was found that the most important variable for th e yield is the rigid solids content, followed by pressure, cake thickn ess and compaction rate. A central composite design procedure was then applied to identify optimum conditions. The highest extraction yield (983.6 g kg(-1)) was obtained at low cake thickness (9 mm), high press ure (7598 kPa) and high solids content (450 g kg(-1)). This extraction yield is much higher than the yield obtained in commercial operations (<850 g kg(-1)). Furthermore, this result was obtained within a very short time (the time of the extraction phase at constant outflow rate, ie about 1 min), while industrial operations usually last 1 h or long er.