In-house validated analytical methods into the OLEUM Databank
The work carried out within the analytical work packages (3 and 4) has delivered a series of analytical methods that aim at a improving the control of virgin olive oil quality and authenticity. These methods have resulted from an exhaustive research in the first period of the project in which different approaches have been tested, optimization of variables has been carried out, and a high number of virgin olive oil samples with different origins, quality and compositional characteristics have been analysed. All this research converges in the exercise of validation of selected methods coordinated by the work package 6 for the technology transfer and the networking (QUB and Fera). The objective is to check the methods in a wide spectrum of labs and end users, to see their performance, and collect feedbacks that can be highly beneficial to promote their use in routine control.
The full validation activity (pre-trials, already concluded, followed by trial proper phase, in progress) is focused on:
i) the “Quantitative Panel test” that includes the analysis of volatile compounds by a targeted SPME-GC-FID/MS method (CSIC, ITERG, UB, UNIBO, UNIUD, UNIPG, NESTEC) developed in parallel with a rapid untargeted SPME-GC-MS screening approach (UB) and the use of two new Reference Materials for sensory analysis (CSIC, UNIBO, EUROFINS, ITERG, IPTPO, UZZK, ZRS);
ii) an UHPLC-DAD method (AUTH) to quantify the polar phenolic compounds (so called “polyphenols”) in relation with the health claim (hydroxytyrosol, tyrosol and derivative compounds);
iii) a revised approach for the preparative phase by HPLC-UV-Vis (UNIBO) or SPE (CSIC) of fatty acid ethyl esters and their analysis by GC-FID
iv) a new method for the GC analysis of free and esterified sterols (UNIUD).
In the last months, OLEUM project has delivered also results from studies that have served to carry out the selection of the four methods previously detailed and has led to the next steps in the project. All the proposed analytical solutions have been already in-house validated and, also if some of them have not been selected by the validation exercise, still are valuable results that are going to be included in a repository, the OLEUM Databank (WP5, JRC). These methods are those based on fast gas chromatography (UNIBO), GC-IMS (UNIBO) and NMR (EUROFINS) as untargeted approaches for the quality discrimination of samples based on profiles in volatile and minor compounds, fluorescence spectroscopy (SMART ASSAYS) for the rapid determination of bioactive lipophilic phenolic compounds, electrical impedance spectroscopy (UNIBO) applied as a portable system for the measurement of free acidity, HPLC-RI and GC-FID analytical approached (ITERG, CSIC, EUROFINS, UNIUD, ZRS) to determine triacylglycerol and fatty acid profiles for the evaluation, based on a specific database, of geographical origin of virgin olive oil samples.
Finally, regarding the study on freshness and shelf-life (coordinated by UNIPG), the experiments under different conditions have been finalized and the information has been organized and analysed. This information has served to select the markers that better allows to evaluate the freshness/quality deterioration of olive oils and can be apply to build a predictive model for shelf-life estimation. In the framework of WP5, the document repository and the database under construction will permit to store documents and validated results generated by the OLEUM consortium (WPs 3, 4 & 6) as SOPs, validation reporting files, measurement raw files, descriptors of experiments (Minimum Information for Reporting related to samples, techniques, analytes), import/export MSExcel template, as well as it will be possible to visualize directly the content of the database and to query its content.