Utilization of milk proteins and cereal starches to obtain co-extrudates.

Extrusion of the cereal mixtures with 25% addition of milk proteins induced several changes in the chemical and physico-chemical properties of starch. Coefficient of expansion was close to the coefficient of natural cereal flours, but the extrudates were characterized by higher water absorption. Starch was only slightly dextrinized, but it contained more nitrogen compounds and mineral salts, and less free lipids. Solubility and swelling power of the extrudates did not change in a way characteristic for cereal starch and flours. Attention should be given to higher content of dietary fibre, pointing to the formation of the starch-lipids and the starch-protein complexes, less susceptible to enzymatic hydrolysis used. Hence, it can be stated that the latter increase was apparent only. It can be said that a mixture of cereal starch and milk proteins can be used to modify quality of the extruded products of increased protein content. More attention should be devoted to biochemical characteristics of the protein added, as this largely determines quality of the extruded starch-protein products.