Short communication: Variations in major mineral contents of Mediterranean buffalo milk and application of Fourier-transform infrared spectroscopy for their prediction

Abstract

The aims of this study were (1) to assess variability in the major mineral components of buffalo milk, (2) to estimate the effect of certain environmental sources of variation on the major minerals during lactation, and (3) to investigate the possibility of using Fourier-transform infrared (FTIR) spectroscopy as an indirect, noninvasive tool for routine prediction of the mineral content of buffalo milk. A total of 173 buffaloes reared in 5 herds were sampled once during the morning milking. Milk samples were analyzed for Ca, P, K, and Mg contents within 3h of sample collection using inductively coupled plasma optical emission spectrometry. A Milkoscan FT2 (Foss, Hillerød, Denmark) was used to acquire milk spectra over the spectral range from 5,000 to 900 wavenumber/cm. Prediction models were built using a partial least square approach, and cross-validation was used to assess the prediction accuracy of FTIR. Prediction models were validated using a 4-fold random cross-validation, thus dividing the calibration-test set in 4 folds, using one of them to check the results (prediction models) and the remaining 3 to develop the calibration models. Buffalo milk minerals averaged 162, 117, 86, and 14.4mg/dL of milk for Ca, P, K, and Mg, respectively. Herd and days in milk were the most important sources of variation in the traits investigated. Parity slightly affected only Ca content. Coefficients of determination of cross-validation between the FTIR-predicted and the measured values were 0.71, 0.70, and 0.72 for Ca, Mg, and P, respectively, whereas prediction accuracy was lower for K (0.55). Our findings reveal FTIR to be an unsuitable tool when milk mineral content needs to be predicted with high accuracy. Predictions may play a role as indicator traits in selective breeding (if the additive genetic correlation between FTIR predictions and measures of milk minerals is high enough) or in monitoring the milk of buffalo populations for dairy industry purposes.

Genetic analysis on infrared-predicted milk minerals for Danish dairy cattle

“…Prediction of K could depend on milk components that are related to osmotic equilibrium in milk, such as lactose. The MIR-based prediction models for K in milk have been built, though model performance varied from moderate to good among studies (Soyeurt et al, 2009;Stocco et al, 2016;Visentin et al, 2016;Franzoi et al, 2019).…”

Detailed macro- and micromineral profile of milk: Effects of herd productivity, parity, and stage of lactation of cows of 6 dairy and dual-purpose breeds

“…Few studies have dealt with the genetics of the mineral composition of milk (van Hulzen et al, 2009;Buitenhuis et al, 2015), in particular because of the large number of individual milk samples that would need to be analyzed and the consequent costs. The use of indirect predictions, such as those based on infrared spectroscopy, provides results with variable accuracy (Soyeurt et al, 2009;Stocco et al, 2016;Malacarne et al, 2018) and needs further evaluation. However, in a study to estimate genetic parameters and detect quantitative trait loci for minerals in 456 Danish Holstein and 436 Danish Jersey cows, Buitenhuis et al (2015) showed that the minerals in milk, in particular Ca, P, Mg, and Zn, have high heritability (0.57, 0.62, 0.60, and 0.41, respectively).…”

“…In any case, despite the technological advances in analytical methods (Lucey et al, 2017), the use of specific laboratory analysis is almost cost prohibitive for application at the population level, as well as being time consuming. On the other hand, for those minerals predicted with sufficient accuracy (i.e., Na, P, and Ca), Fourier-transform infrared spec-troscopy could be a good compromise between time and cost of analysis, and a useful tool, especially if applied in selective breeding programs in cows (Soyeurt et al, 2009) and in buffaloes (Stocco et al, 2016).…”

Factors affecting variations in the detailed fatty acid profile of Mediterranean buffalo milk determined by 2-dimensional gas chromatography

“…Buffalo milk is a rich source of nutrients and therefore plays an important role in human nutrition, particularly in developing countries (e.g., ~70% of buffalo milk is produced in India; FAOSTAT 2013). Indeed, buffalo milk has higher contents of protein and fat (Ahmad et al, 2013) and minerals (Stocco et al, 2016) than cow milk, whereas some specific classes of gangliosides seem to be only present in buffalo milk (Colarow et al, 2003). The high fat content of buffalo milk makes it also highly suitable for processing (Menard et al, 2010), and in developed countries it is mainly used for the production of a variety of foodstuffs, such as butter, butter oil (ghee), soft and hard cheeses, condensed and evaporated milk, ice cream, yogurt, buttermilk, and in Italy, the highly popular buffalo mozzarella obtained under the European Union's protected designation of origin scheme.…”