Variation of major mineral contents in Mediterranean buffalo milk and application of Fourier Transform Infrared spectroscopy for their indirect prediction
Minerals are important for many physiological functions and those contained in milk are actively involved in cheese manufacture. Moreover, milk minerals content is considered an indirect index of udder health in dairy cows. The aims of this study were to characterize mineral components (i.e., calcium, phosphorus, magnesium and potassium) in buffalo milk, to investigate their sources of variation and to test the effectiveness of Fourier Transform Infrared spectroscopy (FTIR) for their indirect prediction. A total of 173 buffaloes reared in five herds were milk sampled once during morning milking. Samples were analysed for calcium, phosphorus, potassium and magnesium within 3 h from collection using Inductively Coupled Plasma (ICP-OES). MilkoScan FT2 (Foss, Hillerød, Denmark) was used for the acquisition of milk spectra over the spectral range from 5000 to 900 wavenumber × cm-1179. Buffalo milk minerals (mg/L of milk) averaged 1,620, 144, 1,172 and 857 for calcium, magnesium, phosphorus and potassium, respectively. Herd and days in milk were the most important sources of variation for the former traits. Parity slightly affected only calcium and potassium. Coefficients of determination between the predicted and measured values in cross-validation (1-VR) were 0.71, 0.70, 0.72 for calcium, magnesium and phosphorus, respectively, whereas potassium exhibited a low accuracy (1-VR = 0.55). Our findings indicate that FTIR predictions could be used to assess buffalo milk components applying this rapid and non-invasive technique in the dairy industry and at the population level for breeding purposes.