NATURAL ANTIOXIDANTS IN THE UNSAPONIFIABLE FRACTION OF VIRGIN OLIVE OILS FROM DIFFERENT CULTIVARS

An investigation on carotene, alpha-tocopherol and squalene contents o f olives from six different cultivars and 15 virgin olive oils produce d in Molise region in 1995 was carried out. Olives were harvested at d ifferent stages of ripeness and oil was extracted in industrial plants by pressure or centrifugation systems. The concentration of carotenes , alpha-tocopherol and squalene have been correlated, both in fruit an d oil samples, with the olive ripeness index. In particular a signific ant linear correlation (R-2 = 0.95) has been found between olive ripen ess index and olive carotene content. In order to evaluate the stabili ty of the extracted oil, a 6 month storage test at room temperature in the dark has been carried out. In addition to the nutritional relevan ce of beta-carotene and alpha-tocopherol, the compounds studied are al so characterised by antioxidant activities. Within the same cultivar, tocopherol and squalene stability was inversely related to the degree of ripeness. In general, storage losses ranged, probably due to differ ent antioxidant mechanisms, from 0 to 10% for carotene, from 14 to 32% for tocopherol and from 26 to 47% for squalene. (C) 1998 SCI.