Species discrimination of terrestrial processed animal proteins by laser-induced breakdown spectroscopy (LIBS) based on elemental characteristics

Description of the subject. This research presents a novel approach for species discrimination of terrestrial processed animal proteins (PAP) using laser-induced breakdown spectroscopy (LIBS) as an alternative technique for determining feed safety. Objectives. To explore the correlation between LIBS results and elemental composition. To assess the potential of LIBS spectroscopic methods for species discrimination of terrestrial PAP. Method. A total of 42 reliable terrestrial PAP samples of ovine, bovine, porcine, and poultry origin were analyzed and LIBS spectra were innovatively collected from the separated bone fraction. Partial least squares-discriminant analysis (PLS-DA) models were performed on the dataset. Results. Significant differences were found in the element compositions (carbon, nitrogen, hydrogen, calcium, sodium, potassium, magnesium, zinc, strontium and barium, p < 0.05) of PAP from different sources, which indicated a high potential for species discrimination. High-marked LIBS spectral characteristics (21 variables) related to six elements (calcium, sodium, magnesium, zinc, strontium and barium) for different species of terrestrial PAP samples were found out. PAP from the four tested species could be well classified with high sensitivity and specificity (> 0.90), while the ruminant and non-ruminant PAP could be thoroughly discriminated. For the discriminant analysis of ruminant-derived components in terrestrial PAPs, the detection of 10%-40% adulteration can be achieved and the correct rate is about 95%. Conclusions. This study demonstrates that LIBS can mostly exhibit the elemental composition of different terrestrial PAP, and can be a promising method for discriminating the different animal species or animal groups (ruminant/non-ruminant) involved in terrestrial PAPs.