title: Short communication: predictive ability of Fourier-transform mid-infrared spectroscopy to assess CSN genotypes and detailed protein composition of buffalo milk.
abstract: The aim of this work was to test the applicability of Fourier-transform mid-infrared spectroscopy (FT-MIR) for the prediction of the contents of casein (CN) and whey protein fractions in buffalo milk. Buffalo milk samples spectra were collected using a MilkoScan FT2 (Foss, Hillerød, Denmark) over the spectral range from 5,000 to 900 wavenumber × cm(-1). Contents of protein fractions, as well as CSN1S1 and CSN3 genotypes, were assessed by reversed phase HPLC. The highest coefficients of determination in cross-validation (1 - VR) were obtained for the contents (g/L of milk) of total protein and CN (1 - VR=0.92), followed by the content of β-CN, total whey protein, and αS2-CN (1 - VR of 0.87, 0.77, and 0.63, respectively). Conversely, contents of αS1-CN, γ-CN, glycosylated-κ-CN, total κ-CN, and whey protein fractions were predicted with poor accuracy (1 - VR <0.51). When protein fractions were expressed as percentages to total protein, 1 - VR values were never greater than 0.61 (β-CN). Only 56 and 70% of the observations were correctly classified by discriminant analysis in each of 2 groups of CSN1S1 and CSN3 genotypes, respectively. Results showed that FT-MIR spectroscopy is not applicable when prediction of detailed milk protein composition with high accuracy is required. Predictions may play a role as indicator traits in selective breeding, if the genetic correlation between FT-MIR predictions and measures of milk protein composition are high enough and predictions of protein fraction contents are sufficiently independent from the predicted total protein content.
authors.affiliation: Department of Comparative Biomedicine and Food Science, Animals and Environment (DAFNAE) University of Padova, 35020 Legnaro, Padova, Italy. Electronic address: valentina.bonfatti@unipd.it.
authors.forename: V
authors.initials: V
authors.lastname: Bonfatti
authors.affiliation: Department of Agronomy, Food, Natural resources, Animals and Environment (DAFNAE) University of Padova, 35020 Legnaro, Padova, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Cecchinato
authors.affiliation: Department of Comparative Biomedicine and Food Science, Animals and Environment (DAFNAE) University of Padova, 35020 Legnaro, Padova, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Carnier
mesh_terms: D000818:Animals; D002020:Buffaloes / Q000235:genetics*; D002364:Caseins / Q000032:analysis; D003718:Denmark; D005838:Genotype; D008892:Milk / Q000737:chemistry*; D010641:Phenotype; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D000067816:Whey Proteins / Q000032:analysis
chemical_list: D002364:Caseins; D000067816:Whey Proteins
keywords: buffalo milk; casein fractions; protein composition; spectroscopy