EXTRACTION OF THE OIL FROM THE OLIVE PAST ES BY BIOLOGICAL AND NOT CONVENTIONAL INDUSTRIAL TECHNICS

Experiments of olive oil extraction, from the Leccino Dritta and Carol eo varieties, by the continous centrifugation system were carried out, comparing two process techniques, which were: a) double olives crushi ng; b)treatment of the olive pastes (obtained grinding just one the ol ives) by the Olivex (R)-enzymatic complex with activities prevalently pectolitic. These techniques cause both (the first mechanically, the s econd chemically) the disintegration of those oleiferous paste cells, that are still intact after a single grinding of the olives, inducing an additional milling effect. The results of this comparative study po inted out that the single grinding carried out by the crushers at the moment available is a not very efficacious method, and is without doub t the main causal factor of the incomplete oil extraction. The techniq ues above mentioned, in fact, induced both a considerable increase of the oil percentage extracted, although the fat rate of the olive resid ues appeared still rather significant: that showed that the optimizati on of the first preparation step of the olive paste (crushing) was a p roblem no very easy to resolve. The effect of the techniques based on the enzymatic formulation use, however, resulted still more significan t, because this technological adjuvant causes the breaking of the oil- water and oil-solids emulsions too. Besides the oils obtained by the b iological techniques showed slightly lower values of the: K232, K270, humidity and impurities percentage, chlorophyllic and phaephytinic pig ments content, chlorophyllic and carotenoids indices, purity of chroma (sigma%), Naudet index of the integral colour; and higher of the: R r atio, pholyphenols and o-diphenols content, GQ11 and GQ12 global quali tative indices, limpidity, brightness of value (h%), total triterpenic alcohols content, induction time (evaluated by the accelerated Swift t est), indicating a longer shelf-life. Finally they got a higher sensor ial score