title: New approach to optimize near-infrared spectra with design of experiments and determination of milk compounds as influence factors for changing milk over time.
abstract: The optimization of near-infrared spectroscopic parameters was realized via design of experiments. With this new approach objectivity can be integrated into conventional, rather subjective approaches. The investigated factors are layer thickness, number of scans and temperature during measurement. Response variables in the full factorial design consisted of absorption intensity, signal-to-noise ratio and reproducibility of the spectra. Optimized factorial combinations have been found to be 0.5mm layer thickness, 64 scans and 25°C ambient temperature for liquid milk measurements. Qualitative analysis of milk indicated a strong correlation of environmental factors, as well as the feeding of cattle with respect to the change in milk composition. This was illustrated with the aid of near-infrared spectroscopy and the previously optimized parameters by detection of altered fatty acids in milk, especially by the fatty acid content (number of carboxylic functions) and the fatty acid length.
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, CCB-Center for Chemistry and Biomedicine, Leopold-Franzens University, Innrain 80/82, 6020 Innsbruck, Austria.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: De Benedictis
authors.affiliation: Institute of Analytical Chemistry and Radiochemistry, CCB-Center for Chemistry and Biomedicine, Leopold-Franzens University, Innrain 80/82, 6020 Innsbruck, Austria. Electronic address: Christian.W.Huck@uibk.ac.at.
authors.forename: Christian
authors.initials: C
authors.lastname: Huck
mesh_terms: D000818:Animals; D002417:Cattle; D005062:European Union; D005227:Fatty Acids / Q000032:analysis*; D008892:Milk / Q000737:chemistry* / Q000592:standards; D015203:Reproducibility of Results; D059629:Signal-To-Noise Ratio; D019265:Spectroscopy, Near-Infrared / Q000379:methods* / Q000592:standards; D013997:Time Factors
chemical_list: D005227:Fatty Acids
keywords: DoE (design of experiments); European Union (EU); Fatty acids; Milk; Multivariate data analysis (MVA); NIR; Optimization