The effects of harvest and extraction methods on the antioxidant content (phenolics, α-tocopherol, and β-carotene) in virgin olive oil

We studied the effects of harvesting and two processing systems (two-phase centrifugation and three-phase centrifugation) on olive oil quality. Oils extracted from high quality olives do not differ in free acidity, peroxide value and ultraviolet light absorption. Nor was the fatty acid composition affected. However, the antioxidant content of the oil was higher from green olives than from ripe olives. On the other hand, we determined that neither extraction method affects the presence of alpha-tocopherol and beta-carotene, however, the phenolic content is higher in the two-phase method due to the addition of lukewarm water that is used to dilute the olive paste. (C) 2002 Elsevier Science Ltd. All rights reserved.