Olive oil quality and authenticity methods based on sterol analysis: a review

Virgin olive oil (VOO) is highly regarded worldwide not only for its distinctive sensory characteristics but also for its widely recognized health benefits, positioning it as one of the most valuable vegetable oils. Nevertheless, these desirable properties also make VOO a frequent target of food fraud, including issues related to the verification of geographical origin, mislabeling of the commercial category, or blending with other vegetable oils. Sterols, a group of minor compounds within the unsaponifiable fraction of olive oil, are considered key markers for evaluating both quality and authenticity. Several factors could influence the sterol composition, such as the geographical region, olive cultivar, and processing techniques. Gas chromatography (GC) coupled with flame ionization detection (FID) or mass spectrometry (MS) yet remains the most commonly used standard approach for sterols analysis, despite certain inherent limitations. However, liquid chromatography (LC), particularly when combined with MS, has also gained increasing interest as an effective alternative. Additionally, methods including ambient MS or spectroscopy have also been proposed for sterol profiling. This review aims to provide an overview of the role of sterols in ensuring VOO quality and authenticity, current methodologies used for their analysis, as well as key markers for detecting fraudulent practices in olive oil. • High market value makes VOO a frequent target of food fraud. • Sterols are key markers for evaluating both quality and authenticity. • Several factors influence sterol composition: geographic, botanical, and processing techniques. • An overview of the role of sterols in the assessment of VOO quality and authenticity is provided. • Both methods and key markers for detecting fraudulent practices are discussed.