*3.2. UV-Visible Spectroscopy*

In the UV and the short-wavelength part of the visible region (below 500 nm) characteristic electronic absorption of the whey proteins, fats, and some vitamins could be detected in diluted milk samples, while water is virtually transparent up to 900 nm. This region is not often used for milk spectrophotometric analysis because of very intensive light scattering on the casein micelles and the necessity of sample dilution and pretreatment; the rare examples include the methods for determination of casein [54] and fat [56]. Some scattering-based techniques for fat and protein spectroscopic determination [64–67] exploit the longer wavelengths part of the visible spectrum often along with the short-wavelengths part of the NIR region (below 1100 nm). The chief advantage of this approach is the possibility to develop cheap, portable, and easy-to-use analytical devices with CCD or CMOS silicon photodetectors.
