1. Technical developments

Without detailing the history of this technology, we can say that the birth of extrusion and cook-extrusion in the food industry took place in three main periods:

• First period. The era of empiricism: in 1797, screw extrusion made its debut in metallurgy, before penetrating the rubber industry around 1845 (hot forming of gutta-percha sheathing: electrical insulation). The transfer of technology continued in the plastics industry between 1925 and 1935 in Germany, where thermoplastic extruders derived directly from rubber extruders. On the other hand, screw extrusion appeared in the food industry at the beginning of the 19th century. The first patents are to be found in the meat and cereal processing sectors, where the main function of extrusion was to form products under pressure, possibly after preheating. This continuous process gradually...