EFFECT OF EXTRACTION SYSTEMS ON THE QUALITY OF VIRGIN OLIVE OIL

Research has been carried out to ascertain the effects of different processing systems on olive oil quality. Tests were performed in industrial oil mills that were equipped with both pressure and centrifugation systems. Results show that oils extracted from good quality olives do not differ in free fatty acids, peroxide value, ultraviolet absorption and organoleptic properties. Polyphenols and o-diphenols contents and induction times are higher in oils obtained from good quality olives by the pressure system because it does not require addition of water to the olive paste. The centrifugation system requires the addition of warm water to the olive paste and helps to obtain oils with a lower con tent of natural antioxidants. Oils obtained from poor-quality or from ripe olives in continuous centrifugal plants are lower in free fatty acids than those obtained by the pressure system.