4. Conclusions
The results indicated that multivariate modelling using the PLS method based on Raman spectra of liquid milk samples was another effective tool for the simultaneous quantitative determination of macronutrients in milk. Fat, protein, carbohydrates and dry matter were quantified in 21 commercial milk samples with RSEPtest errors of 3.4–5.6% relative to the values found applying the IR reference method. Results of a better quality were obtained from a separate PLS model based on IR spectra registered using a single reflection ATR diamond accessory, yielding RSEPtest values of 2.4–4.4%.