Light scattering applications in milk and dairy processing

Milk is a complex biological fluid composed of water, fat, protein, lactose, citric acid, and inorganic compounds (Walstra and Jenness, 1984). Although every constituent plays at least a minor role in the scattering of light, the majority of scattering is due to milk fat globules and proteins. The most prevalent protein in milk is casein, which exists as a colloidal dispersion of particles known as casein micelles. The remaining proteins are referred to as whey proteins. In addition to scattering effects, fat globule size and concentration have been shown to have large effects on transmission measurements (Ben-Gera and Norris, 1968).