Identification of species affiliation and determination of fish eggs adulteration by vibrational spectroscopy and digital colorimetry methods

The efficiency of combining spectroscopic and chemometric methods for identification and classification of salmon, sturgeon and particle fish caviar, as well as for differentiation of natural and imitated samples, has been shown. Analysis of infrared spectra in the near and middle regions made it possible to identify the peculiarities of chemical composition and structure of the samples under study, providing reliable differentiation of natural and imitated caviar. The use of Raman spectroscopy helped to identify characteristic spectral differences related to protein-lipid composition and the presence of carotenoids, which allowed to clearly differentiate the samples. The application of principal component analysis (PCA), hierarchical cluster analysis (HCA) and formal independent modeling of class analogies (SIMCA) algorithms improved classification accuracy, providing separation of samples by fish species. Digital colorometry based on the analysis of optical characteristics in the UV and IR ranges showed to be an affordable and reliable method that can be an alternative to more expensive spectroscopic approaches.