ViewpointA mechanistic approach to analyze extrusion processing of biopolymers by numerical, rheological, and optical methods

•An approach for the analysis of structural changes in extrusion is presented.•The approach divides the extrusion process into interrelated sections.•Suitable numerical, rheological, and optical methods are proposed.•Extrusion process can be characterized by these methods at mechanistic level.

Although the history of food extrusion processing goes back to the late-1800s, the control of this process and design of new extruded products are still mostly based on empirical knowledge. In this viewpoint, we present an approach which may practically enable the food research to analyze the extrusion processing at a mechanistic level and characterize the decisive process parameters crucial for complex food design. This contribution aims to discuss and exemplify this approach, which is based on the fractionation of the process into interrelated sections. These sections can then be investigated in defined manner using numerical, rheological, and optical methods.