Extrusion processing in the food industry: principles, process variables, applications, and challenges

Extrusion processing is a continuous high-temperature short-time (HTST) technology widely used for manufacturing various food products. It induces starch gelatinization, protein denaturation, and structural transformation under high temperature, pressure, and shear conditions. This review summarized the basic principles, equipment configuration, and key process variables such as moisture content, barrel temperature, and screw speed, emphasizing their effects on the physicochemical and textural properties of extruded foods. Applications in starch-based snacks and high-moisture meat analogs (HMMA) are discussed, along with the impact on nutritional quality and the potential of extrusion–fermentation hybrid processes. Despite its advantages in efficiency and versatility, reproducing consistent product characteristics during large-scale production remains challenging due to the complexities associated with scaling up from pilot- to industrial-scale operations. Overall, extrusion technology provides an effective and sustainable approach for developing innovative, sustainable, and high-value food materials.