External cavity-quantum cascade laser (EC-QCL) spectroscopy for protein analysis in bovine milk

• DOI: 10.1016/j.aca.2017.02.003
• Publication Date: 2017-02-22T14:32:15Z
• Authors: Julia Kuligowski; Andreas Schwaighofer; Mirta Raquel Alcaráz; Guillermo Quintás; Helmut Mayer; Máximo Vento; Bernhard Lendl
• Keywords: 2. Zero hunger; External Cavity-Quantum Cascade Laser (Ec-Qcl) Spectroscopy; Science-based calibration (SBC); Spectrum Analysis; Milk analysis; 04 agricultural and veterinary sciences; Milk Proteins; Milk Analysis; Milk; 0404 agricultural biotechnology; Protein Analysis; Science-Based Calibration (Sbc); Calibration; https://purl.org/becyt/ford/1.4; Protein analysis; Animals; Regression Analysis; Cattle; Lasers, Semiconductor; https://purl.org/becyt/ford/1; External cavity-quantum cascade laser (ECQCL) spectroscopy; Mid-infrared (IR); Mid-Infrared (Ir)

The analytical determination of bovine milk proteins is important in food and non-food industrial applications and yet, rather labour-intensive wet-chemical, low-throughput methods have been employed since decades. This work proposes the use of external cavity-quantum cascade laser (EC-QCL) spectroscopy for the simultaneous quantification of the most abundant bovine milk proteins and the total protein content based on the chemical information contained in mid-infrared (IR) spectral features of the amide I band. Mid-IR spectra of protein standard mixtures were used for building partial least squares (PLS) regression models. Protein concentrations in commercial bovine milk samples were calculated after chemometric compensation of the matrix contribution employing science-based calibration (SBC) without sample pre-processing. The use of EC-QCL spectroscopy together with advanced multivariate data analysis allowed the determination of casein, α-lactalbumin, β-lactoglobulin and total protein content within several minutes.