A study of fractionation of milk as a typical biological fluid by digital holographic interferometry

We present the results of a study of milk as a complex biological fluid. The simultaneous occurrence of both direct and reverse sedimentation associated, respectively, with the protein and fat components of milk is demonstrated. Digital holographic interferometry enables the determination of the spatial and temporal changes in the refractive index of the suspension under study caused by fractionation processes with an accuracy of 10$^{-6}$, which exceeds the capabilities of other research methods. The results can be used to create a mathematical model of biological fluid fractionation processes and to develop physical models (phantoms) of such systems.