Dietary fiber in extruded cereals: Limitations and opportunities

Incorporation of dietary fiber in extruded products often leads to reduced expansion volumes and textures that are less preferred by consumers. Nevertheless, soluble fiber provides higher expansion volumes while they affect less the bulk density of extruded products than insoluble fiber. The difference in expansion behavior and related textural properties between soluble and insoluble fiber can be explained by their interactions with starch, differences in water sorption and plasticization behavior but also by the physicochemical transformations they undergo during extrusion. Treatments of insoluble fiber, prior to extrusion, can significantly improve their expansion and textural properties.