Effect of amurca on olive oil quality during storage.

Total phenolic compounds (TPC), antioxidant activity (AA), lipid peroxidation inhibition (percent) (LPOIP), free fatty acid and peroxide values were measured in olive oil samples over the period of 12 months in comparison with oil samples extracted from amurca (olive oil lees) and olive oil samples taken from the bottom of the canister (near amurca) after 12 months of storage. Olive oil samples taken over the period of 12 months possessed decreasing amounts of TPC, AA and LPOIP, which led to increased peroxide and free fatty acid values. In contrast, oil extracted from amurca and olive oil samples taken from the bottom of the container after 12 months of storage possessed significantly higher TPC, AA, LPOIP and consequently lower free fatty acid and peroxide values. These results show that the presence of naturally occurring amurca (sediment) in stored olive oil stabilizes olive oil quality during storage.