Effectiveness of mid-infrared spectroscopy for the prediction of detailed protein composition and contents of protein genetic variants of individual milk of Simmental cows

Abstract

Mid-infrared (MIR) spectroscopy was used to predict the detailed protein composition of 1,517 milk samples of Simmental cows. Contents of milk protein fractions and genetic variants were quantified by reversed-phase HPLC. The most accurate predictions were those obtained for total protein, casein (CN), α(S1)-CN, β-lactoglobulin (LG), glycosylated κ-CN, and whey protein content, which exhibited coefficients of determination between predicted and measured values in cross-validation (1-VR) ranging from 0.61 to 0.78. Less favorable were results for β-CN (1-VR=0.53), α(S2)-CN, and κ-CN (1-VR=0.49). Neither the content of α-LA nor that of γ-CN was accurately predicted by MIR. Predicting the content of the most common milk protein genetic variants (κ-CN A and B; β-CN A¹, A², and B; and β-LG A and B) was unfeasible (1-VR <0.15 for the content of κ-CN genetic variants and 1-VR <0.01 for the content of β-CN variants). The best predictions were obtained for β-LG A and β-LG B contents (1-VR of 0.60 and 0.44, respectively). Results indicated that MIR is not applicable for predicting individual milk protein composition with high accuracy. However, MIR spectroscopy predictions may play a role as indicator traits in selective breeding to enhance milk protein composition. The genetic correlation between MIR spectroscopy predictions and measures of milk protein composition needs to be investigated, as it affects the suitability of MIR spectroscopy predictions as indicator traits in selective breeding.

Phenotypic characterisation of milk technological traits, protein fractions, and major mineral and fatty acid composition of Burlina cattle breed*

“…Second, Pacini et al (2008) highlighted a greater frequency of j-CN B allele in BU cattle breed, which is associated with greater casein content (Vallas et al 2012). De Marchi et al (2009), Bonfatti et al (2011) and Niero et al (2016) reported values of casein index that were similar to the one calculated in the present study.…”

Dielectric Properties of Raw Milk as Functions of Protein Content and Temperature

“…They are just used in laboratory and are not capable of real-time or situ detection. The spectroscopy analysis methods, including the visible (Bogomolov et al 2012), infrared (Rutten et al 2011), midinfrared (Bonfatti et al 2011;Botaro et al 2011), near-infrared (Bogomolov and Melenteva 2013;Feng et al 2013;Kalinin et al 2013), and ultraviolet (Dziuba et al 2001;Rukke et al 2010), have been used to determine protein content in milk widely; however, too complex instruments are needed. Moreover, most of them are difficult to be used in real-time detection.…”

Standardization of milk mid-infrared spectrometers for the transfer and use of multiple models

“…Equations based on the full spectrum have been developed for the determination of fine milk components such as fatty acid profiles (Soyeurt et al, 2006;Rutten et al, 2009), protein composition (Bonfatti et al, 2011), minerals (Soyeurt et al, 2009), ketone bodies (van Knegsel et al, 2010), citrate (Grelet et al, 2016), and lactoferrin (Soyeurt et al, 2007). Other studies have focused on FT-MIR spectra to build equations predicting technological properties of milk such as milk acidity ), ability to coagulate, firmness of curd, or cheese yield (Dal Zotto et al, 2008;Colinet et al, 2015).…”