External cavity-quantum cascade laser (EC-QCL) spectroscopy for protein analysis in bovine milk.
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.
Neonatal Research Unit, Health Research Institute La Fe, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain; Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria.
Julia
J
Kuligowski
Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria.
Andreas
A
Schwaighofer
Laboratorio de Desarrollo Analítico y Quimiometría, FBCB, Universidad Nacional del Litoral-CONICET, Ciudad Universitaria, 3000 Santa Fe, Argentina.
Mirta Raquel
MR
Alcaráz
Human & Environmental Health & Safety (HEHS), Leitat Technological Center, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain; Unidad Analítica, Health Research Institute La Fe, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain.
Guillermo
G
Quintás
Food Chemistry Laboratory, BOKU - University of Natural Resources and Life Sciences, Muthgasse 11, 1190 Vienna, Austria.
Helmut
H
Mayer
Neonatal Research Unit, Health Research Institute La Fe, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain; Division of Neonatology, University & Polytechnic Hospital La Fe, Avenida Fernando Abril Martorell 106, 46026 Valencia, Spain.
Máximo
M
Vento
Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9/164-UPA, 1060 Vienna, Austria. Electronic address: bernhard.lendl@tuwien.ac.at.
Bernhard
B
Lendl
D000818:Animals; D002138:Calibration; D002417:Cattle; D054023:Lasers, Semiconductor; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000032:analysis*; D012044:Regression Analysis; D013057:Spectrum Analysis
D008894:Milk Proteins
External cavity-quantum cascade laser (EC-QCL) spectroscopy; Mid-infrared (IR); Milk analysis; Protein analysis; Science-based calibration (SBC)