Quality parameters of olive oil from stoned and nonstoned Koroneiki and Megaritiki Greek olive varieties at different maturity levels

Virgin olive oil is a natural functional food and its beneficial role in health as an integral ingredient of the Mediterranean diet is universally recognized. The effects of olive pitting, degree of ripeness and variety (Greek varieties Koroneiki and Megaritiki) were investigated on the physicochemical characteristics, antioxidant constituent contents and capacity and on the fatty acid profile of olive oil. Ripeness resulted in a decrease (P<0.05) in phenolic and tocopherol contents and the unsaturated/saturated and C18:1 omega-9/C18:2 omega-6 fatty acid ratios. The pitting technique resulted in a significant increase in phenolic and tocopherol contents, in most cases, without significantly affecting the fatty acid profile and sums. Olive oils from the Koroneiki variety showed significantly higher (P<0.05) monounsaturated/polyunsaturated fatty acid ratios, which are particularly important for the stability of the oil against oxidation. It was concluded that olive oil from pitted olives maintains a high content in bioactive compounds and a high level of antioxidant activity.