Analysis of milk by FT-Raman spectroscopy

• Fat, protein, carbohydrates and dry matter were quantified in commercial cow milk.
• For the first time macronutrients were quantified using FT Raman spectroscopy.
• Results of a better quality were obtained using single reflection FTIR ATR spectra.

Fat, protein, carbohydrates and dry matter were quantified in commercial bovine milk samples, with the relative standard errors of prediction (RSEP) in the 3.4–6.1% range, using the partial least squares (PLS) method based on Raman spectra of liquid milk samples. Results of a better quality were obtained from a PLS model derived from IR spectra registered using single reflection ATR diamond accessory, which yielded RSEP values of 2.4–4.4%. The data indicated IR single reflection ATR spectroscopy and Raman spectroscopy in combination with multivariate modelling using the PLS method, allowed for the reliable, simultaneous quantitative determination of macronutrients in milk. The low signal to noise ratio of Raman spectra affects the quality of fat quantification especially for strongly defatted milk samples.

Figure optionsDownload as PowerPoint slide