The data of the literature on the impact factors of the extrusion cooking on physical and chemical properties of food proteins, biological value and digestibility have been discussed. Extrusion cooking is a high temperature short-time process, characterizing by a minimal loss of nutrients. and biologically active substances compared to other methods of heat treatment of food. Studies of the properties of protein-containing products, protein isolates and concentrates in the extrusion are examined in different ways: the inactivation of antinutritional factors; improvement in digestibility and availability; changes in the content and chemical modification of amino acids; Maillard reactions involving amino acids; mutual enrichment of protein mixtures during the composite food extrusion; formation of functional technological properties of the extruded protein products.