Chemical characterization and oxidative status of olive oils extracted by expeller pressing and supercritical CO2 extraction: Impact on quality standards and their regulatory recognition

Abstract

Innovative extraction methods, such as the sequential combination of expeller pressing and supercritical CO₂ (SC-CO₂), were applied to obtain high quality olive oil (OO) while improving sustainability and reducing environmental impact. In this study, the physicochemical properties of the oils obtained at the Spanish Association for Standardization and Certification were evaluated following the quality standards established by the European Union and the International Olive Council. The results revealed that the combined yield of the sequential process was 87 %, significantly higher than centrifugation-based extraction methods, which typically yield around 75–80 %. The oils showed high phenolic concentrations (1013–1855 mg/kg), and superior oxidative stability, underlining their potential for functional and premium market applications. Acidity and peroxide values are lower than those established for virgin olive oil. However, some parameters (e.g., K232 and K270) exceeded these limits, probably due to the unique extraction processes employed. These results highlight the need to update regulations to include new extraction methods and validate these oils as high-value sustainable products.