Rapid Determination of Fish Species of Raw and Heat-Treated Fish Meat Using Proteomic Species-Specific Markers.

Research background: The main problem regarding the authenticity of fish meat lies mainly in misleading labelling or substitution of species, like the replacement of valuable fish meat with species of lower value or species originating from illegal fishing. For these reasons, the need has arisen for adequate analytical methods to detect food fraud.

Experimental approach: The aim of this study is to differentiate six fish species-carp, mackerel, pike, pollock, salmon and trout-based on differences in their protein composition using two mass spectrometry methods. Matrix-assisted laser desorption/ionization-time ff flight mass spectrometry (MALDI-TOF MS) was employed to identify characteristic species-specific m/z values to differentiate raw and cooked fish meat. Additionally, liquid chromatography-electrospray ionization-quadrupole-time tf flight (LC-ESI-Q-TOF) was used to determine specific amino acid sequences in carp and salmon, selected as model species.

Results and conclusions: Distinct species-specific m/z markers were identified for all six fish species, enabling their differentiation in both raw and processed form. In carp and salmon, hundreds of peptide sequences were detected, leading to the identification of a panel of peptide markers that determine both the fish species and the type of meat processing. The results confirm that mass spectrometry-based proteomic approaches can serve as effective tools for the authentication of fish meat.

Novelty and scientific contribution: This study shows that it is possible to use two complementary mass spectrometry techniques for reliable and rapid authentication of fish species. The identification of specific peptide markers and species-specific m/z values contributes to the improvement of food authenticity control and provides a powerful approach to the detection of fish meat adulteration.