Potential estimation of major mineral contents in cow milk using mid-infrared spectrometry

Abstract

Milk and dairy products are a major source of minerals, particularly calcium, involved in several metabolic functions in humans. Currently, several dairy products are enriched with calcium to prevent osteoporosis. The development of an inexpensive and fast quantitative analysis for minerals is required to offer dairy farmers an opportunity to improve the added value of the produced milk. The aim of this study was to develop 5 equations to measure Ca, K, Mg, Na, and P contents directly in bovine milk using mid-infrared (MIR) spectrometry. A total of 1,543 milk samples were collected between March 2005 and May 2006 from 478 cows during the Walloon milk recording and analyzed by MIR spectrometry. Using a principal component approach, 62 milk samples were selected by their spectral variability and separated in 2 calibration sets. Five outliers were detected and deleted. The mineral contents of the selected samples were measured by inductively coupled plasma atomic emission spectrometry. Using partial least squares combined with a repeatability file, 5 calibration equations were built to estimate the contents of Ca, K, Mg, Na, and P in milk. To assess the accuracy of the developed equations, a full cross-validation and an external validation were performed. The cross-validation coefficients of determination (R 2 cv) were 0.80, 0.70, and 0.79 for Ca, Na, and P, respectively (n = 57), and 0.23 and 0.50 for K and Mg, respectively (n = 31). Only Ca, Na, and P equations showed sufficient R 2 cv for a potential application. These equations were validated using 30 new milk samples. The validation coefficients of determination were 0.97, 0.14, and 0.88 for Ca, Na, and P, respectively, suggesting the potential to use the Ca and P calibration equations. The last 30 samples were added to the initial milk samples and the calibration equations were rebuilt. The R 2 cv for Ca, K, Mg, Na, and P were 0.87, 0.36, 0.65, 0.65, and 0.85, respectively, confirming the potential utilization of the Ca and P equations. Even if new samples should be added in the calibration set, the first results of this study showed the feasibility to quantify the calcium and phosphorus directly in bovine milk using MIR spectrometry.

Genetic parameters for milk mineral content and acidity predicted by mid-infrared spectroscopy in Holstein–Friesian cows

“…Moreover, van Hulzen et al (2009) and Toffanin et al (2015) documented a phenotypic coefficient of variation between 9% and 12% for measured Ca and P in milk of Holstein − Friesian cows. Soyeurt et al (2009) investigated the feasibility of MIRS to predict the content of milk minerals using the ICP-AES without previous mineralization as the reference method. Despite differences in pre-treatment for ICP-AES as well as the data originating from two separate populations of cows, similar means and coefficients of variation were observed between the present study and the aforementioned study of Soyeurt et al (2009).…”

“…Reported heritability estimates for milk TA range from 0.17 to 0.23 in Italian Holstein cows Cecchinato et al, 2011). To our knowledge, only Soyeurt et al (2008a) used 5502 multi-breed cows to estimate genetic parameters for mineral content of milk predicted by mid-IR spectroscopy (MIRS) and they reported heritabilities of 0.42 and 0.47 for Ca and P, respectively.…”

“…MIRS has already been proposed to predict milk Ca and P (Soyeurt et al, 2008a;Toffanin et al, 2015), thereby providing a low-cost approach to generate large datasets useful for genetic evaluations. The objective therefore of the present study was to estimate genetic parameters for milk Ca, P and TA predicted by MIRS as well as the genetic correlations between these traits with milk production and quality in Italian Holstein − Friesian cows.…”

New phenotypes for new breeding goals in dairy cattle

“…Encouraging results, although less accurate, were also obtained in the prediction of individual proteins (e.g. lactoferrin, Soyeurt et al, 2007b) or minerals (Soyeurt et al, 2009b).…”

Rapid determination of sodium in milk and milk products by capillary zone electrophoresis

“…The determination of Na in milk products can be performed by several instrumental techniques (Soyeurt et al, 2009;Ehling et al, 2010), including indirect photometric chromatography, ion chromatography, flame atomic absorption spectrometry (FAAS), inductively coupled plasma optical emission spectrometry, inductively coupled plasma atomic emission spectrometry, and mid-infrared spectrometry. Currently, the reference analytical method for the determination of Na in milk and dairy products, validated by the International Organization for Standardization and the International Dairy Federation (ISO/IDF), is based on FAAS (ISO/ IDF, 2007), although this technique requires a laborintensive pretreatment of the sample.…”