High-moisture extrusion cooking of plant proteins has recently gained increasing attention for the production of meat analogues. The combination of heating and subsequent cooling of the protein-water mixture facilitates the texturization to layered or fibrous structures with a meatlike appearance. Up to now, the processes inside the extruder and the long cooling die could not be described exactly, that is why high-moisture extrusion is often regarded as a 'black box.' This article describes the effects of independent process variables such as raw material characteristics as well as extruder and process design on the formation of fibrous structures. Concurrently, the effects of dependent system parameters such as pressure, temperature, and changes at a molecular level with focus on protein-protein interactions have also been taken into consideration. This article shows that a very large number of parameters directly influence the product's quality and must therefore be carefully adjusted to obtain products with fibrous meatlike properties.
