The method of small angle X-ray scattering (SAXS) was adopted in the studies of the structure of potato starch extrudates with: 1. Soybean protein preparation, 2. Whey proteins concentrate, and 3. Acid casein. The range of SAXS scattering changes caused by the structures
formed in the extrudates was analysed. The changes of extrusion conditions of starch – soybean extrudates resulted in forming the objects which exhibited fractal features. The SAXS studies of starch and whey proteins and casein extrudates suggest the existence of highly complicated structures in them. It was also observed that as the extrusion parameters increased the size of scattering objects formed was decreasing.