Extrusion effects on composition, protein digestibility, and functional properties of cold-pressed oilseed cakes

Abstract

Extrusion has the potential to modify the composition, protein digestibility, and functional properties (FP) of raw materials. Extrusion effects on the physicochemical characteristics, composition, protein digestibility, and FP of soybean and canola cakes obtained from the cold-pressing oil extraction, were evaluated. In general, extrusion did not greatly affect the physicochemical properties (aw and pH), and sugar and mineral profiles. Protein content was not affected but some amino acids in soybean as L-aspartic and L-glutamic acid increased up to 8%, while total protein content was enhanced in extruded canola, with no differences in amino acids. In vitro digestibility of canola increased 4%. The soluble/insoluble fiber ratio for both extruded cakes augmented 34%. Water absorption capacity in soybean increased by 12%, while the emulsifying activity index decreased (16–21%) in both by-products. The composition and change in TFP of extruded cakes suggest potential for new applications based on extrusion changes.