Method for determining caseins and serum proteins in raw or low pasteurised dairy products

A method for determining a content of caseins and a content of serum proteins in a liquid foodstuff such as raw or low pasteurized milk, comprising:

• a) forming a solution of said liquid foodstuff by adding a buffer with a predetermined pH, said solution comprising said serum proteins and said caseins, the caseins being in a coagulated form suspended in the solution and the serum proteins being solubilized in the solution;
• b) stirring the solution to form a homogeneous mixture of the serum proteins and caseins;
• c) acquiring a plurality of frontal fluorescence spectra of said mixture, said frontal fluorescence spectra resulting from the excitation of said homogeneous mixture by at least one electromagnetic radiation with a determined wavelength;
• d) diluting the mixture by adding a predetermined quantity of water to separate by filtration the soluble serum proteins from the coagulated caseins suspended in the solution.
• e) acquiring a plurality of right-angle fluorescence spectra of said diluted mixture, said right-angle fluorescence spectra resulting from the excitation of said diluted mixture by at least one electromagnetic radiation with a determined wavelength;
• and
• f) determining the content of caseins and the content of serum proteins of the liquid foodstuff by applying a multi-path analysis to the frontal fluorescence spectra and to the right-angle fluorescence spectra.