The decrease in the health benefits of extra virgin olive oil during storage is conditioned by the initial phenolic profile

Phenols are responsible for the only health claim of virgin olive oil (VOO) recognized by the European Commission EU 432/2012 and the European Food Safety Authority. In this research, we studied the decrease in the phenolic content of 160 extra VOOs (EVOOs) after 12 months storage in darkness at 20 degrees C. Phenolic concentration was decreased 42.0 +/- 24.3% after this period and this reduction strongly depended on the initial phenolic profile. Hence, EVOOs with predominance in oleacein and oleocanthal experienced a larger decrease in phenolic content than oils enriched in other phenols. Complementarily, hydroxytyrosol and oleocanthalic acid increased significantly in aged EVOOs, which allowed their discrimination from recently produced EVOOs. These changes are explained by degradation of main secoiridoids during storage due to their antioxidant properties. Hydroxytyrosol and oleocanthalic acid can be considered markers of olive oil ageing, although they can also provide information about quality or stability.

Automated summary

The research found that the phenolic content of extra virgin olive oil significantly decreases after 12 months of storage, with the reduction strongly dependent on the initial phenolic profile. Additionally, specific phenolic compounds in aged olive oil significantly increased, allowing for differentiation from freshly produced oil. These changes are attributed to the degradation of main secoiridoids during storage, indicating markers of olive oil ageing and providing information about quality or stability.