The knowledge of biopolymer changes by extrusion is very important for a wide range of industrial applications that spreads from extruded food to biodegradable packaging. In this article, the formation of starch-lipid and lipid-protein complexes that occurred during the extrusion cooking of wheat flour with the addition of fatty acids was studied. Results showed that the highest barrel temperature (128.3 degrees C) promoted the formation of starch-lipid complexes in samples made up of wheat starch and wheat flour with the addition of fatty acids. The maximum formation of protein-lipid complexes (68% fatty acid bound to protein) was observed at the highest barrel temperature and water feed content (<22%). This study is a prerequisite for the optimisation of production of expanded extrudates made up of wheat flour and fatty ingredients and for the study of a biodegradable packaging based on by-product of milling wheat (and fat).