Development of innovative analytical strategies for olive oil quality and authenticity assessment
- Autores: Beatriz Quintanilla Casas
- Directores de la Tesis: Stefania Vichi (dir. tes.), Alba Tres Oliver (codir. tes.)
- Lectura: En la Universitat de Barcelona ( España ) en 2022
- Idioma: inglés
- Tribunal Calificador de la Tesis: María Carmen Vidal Carou (presid.), Itziar Ruisánchez Capelastegui (secret.), Enrico Casadei (voc.)
- Programa de doctorado: Programa de Doctorado en Alimentación y Nutrición por la Universidad de Barcelona
- Materias:
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- Resumen
Olive oil (OO) is a highly appreciated food product due to its nutritional value and organoleptic properties, marketed worldwide. In spite of being one of the most regulated food products, its high economic value becomes a motivation for different types of fraudulent practices. Besides, some of the current official control procedures result inefficient to either detect emerging adulterants or verify some label-declared properties on OOs, thus triggering the opportunity of fraud. As a result, the latest official reports from the European Commission place OO on the top of the most notified food products in regards of fraud and non-conformities. In addition to the mistrust on the OO sector, fraudulent practices put food safety on great risk due to the loss of traceability. Therefore, emerging trends in food analysis should be considered in order to develop instrumental tools that support the current reference protocols.
For this reason, the present thesis aims at contributing to guarantee OO quality and authenticity by developing prediction models based on suitable markers as well as the appropriate analytical and chemometric techniques, focusing on the enhancement of the following issues: i) supporting the organoleptic assessment of virgin OOs by the sensory panels, ii) detecting blends of OO with low amounts of other vegetable oils and, iii) verifying the geographical origin of virgin OOs. Pursuing the highest efficiency, authentication models have been developed following innovative untargeted approaches, such as profiling and fingerprinting, given the advantages over traditional target analyses.
Virgin OO chromatographic fingerprints determined by HS-SPME-GC-MS were used to build classification models aiming at different purposes. Fingerprints of virgin OOs sesquiterpene hydrocarbon fraction proved to be successful for geographical authentication, from European label-declared oils to specific geographical indication schemes. This screening tool could serve as an instrumental support for the documental review process, which is currently performed by the control bodies to check the compliance with the mandatory label-declared origin. On the other hand, models based on virgin OO volatile fingerprints resulted the fit-for-purpose screening tool for the assignment of virgin OO commercial category (extra virgin, virgin or lampante OO). In order to provide full support to the sensory panel, together with the last tool focused on olfactory-related compounds, an accurate prediction of taste-related positive attributes in virgin OOs was also achieved by fluorescence spectroscopy.
An untargeted profiling, achieved by a high-throughput technique such as shotgun triacylglycerol high-resolution mass spectrometry, was proposed to build authentication models discriminating genuine from adulterated OOs. The developed models allowed the detection of low concentrations of high-linoleic or high-oleic vegetable oils, including some considered as emergent adulterants. This authentication tool would allow an efficient screening according to the actual OO production rate.
Additionally, a protocol to validate the analytical signal of chromatographic fingerprints has also been suggested. This would be a first step of a comprehensive validation procedure for untargeted methods, which is not currently available and it is required to achieve their transferability as future reference methods. Meanwhile, the promising strategies developed to assess the quality and authenticity of OOs could be soon implemented as screening tools to support the current reference methods and to guide control bodies’ inspections.
