# MALDI-TOF Mass Spectrometry Applications for Food Fraud Detection
## 2 MALDI Applications
### Oils
As described in the work of [PERSON] at al. [61], when the fraud to be revealed concerns the presence of seed oils in EVOO, it may be sufficient to target their TAGs profile to characterize the samples and eventually determine the presence of the adulterant product. In fact, two more applications based on MALDI in conjunction with statistical approaches were successfully developed for the detection of sunflower (or refined) [67] and canola [68] oils in EVOO, respectively, using the TAGs profiles present in the relevant mass spectra. A hardly detectable adulteration is represented by the addition of sunflower oil to poppy seed oil because of the similar fatty acid ratios. In fact, a further application [69] reported the successful MALDI-TOF MS detection of mixtures of sunflower oil with high levels of triolein (high-oleic acid type) down to the 5-10% level, but the same approach failed to discover adulteration of pure poppy seed oil by sunflower oil. Several works were focused on the quality evaluation of edible oils (mainly EVOO). Taking into account that squalene concentrations in olive oil vary considerably depending on the cultivar, its determination in this matrix should be able to discriminate between varieties. Thus, [PERSON] at al. [70] reported on the LDI-TOF MS determination of squalene and derived oxides involved in the biosynthetic pathway of cholesterol in extra virgin olive oil. The same research group used the same matrix-less approach to characterize olive and sunflower oils before and after thermally assisted oxidation [71]. The obtained MS profiles provided information about the identity of thermally induced oxidation products, such as TAGs epoxy/hydroxy, hydroperoxylatives, and \(\beta\)-scission products, making the method a tool to rapidly check the quality of cooking oil. TAGs thermal oxidation of sunflower and olive oils was also studied by [PERSON] at al. two years later [72]. To increase the detection of oxidized components, a chromatographic separation of polar and non-polar compounds was performed on silica gel before MALDI analysis. Tri- and diacylglycerols, TAGs oxidative dimers, oxidized TAGs, and TAGs fragments arising from the \(\beta\)-scission of linoleyl, peroxy, and alkoxy radicals were observed in the relevant spectra. For authentication and characterization purposes, detailed MALDI TAG profiles of olive oils were also successfully obtained from samples coming from six different cultivars [73] and of two different varieties grown in the same area at different olive ripening stages [74]. [PERSON] and co-workers [75] optimized a matrix solid-phase dispersion (MSPD) procedure to extract several phospholipids from olive fruit and oil samples, exploiting the ability of the sorbent (TiO\({}_{2}\) nanoparticles) to selectively interact with the phosphate group of the analyte by a chelating bidentate bond. After elution, MALDI-TOF analysis in both positive and negative ion modes was performed. The method proved to possess a great potential in lipidomic fingerprinting of olive samples for quality control. Different analytical instrument, namely MALDI, GC, and LC-MS, were synergistically used to perform a study of the lipid composition of commercial extra virgin and virgin olive oils [76], in an attempt to define specific lipid patterns and/or establish a set of lipid markers representing the identity of a specific oil. Significant differences between EVOOs and VOOs were found, and five classes of phospholipids were identified in the polar lipid fraction, with remarkable variations in phosphatidylcholine. MALDI-SpiralTOF was employed [77] to obtain TAG fingerprints relevant to sesame, sunflower, and olive oils to draw traceability and authenticity information. The application of PCA allowed the discrimination of Istrian olive oils from those coming from other Croatian coastal regions.