Extrusion Cooking Technology in Food Applications: A Mini Review

Abstract

Extrusion cooking is a contemporary and sustainable approach in food industries used to produce a wide range of improved products such as ready to eat breakfast cereals, confectionary snack products, meat analogue, dairy products and pet food among others. During extrusion cooking, modification in the structure of raw materials occurs such as starch gelatinization, protein denaturation, destruction of anti-nutritional factors and microorganisms using cold or hot extrusion operating as single or twin screw design. Basically raw materials are fed into the extruder barrel and the screw(s) then convey the food down it. Further along the barrel, lesser flights restrict the volume and increase the resistance to movement of the food. As a result, it fills the barrel and the spaces between the screw flights and becomes compressed. As it moves along the barrel, the screw cooks the material into a semi-solid, plasticized mass. The food is then passed to the section of the barrel having the negligible flights, where pressure and shear force is further increased. Finally, it is forced through an opening die at the discharge end of the barrel. In comparison with other processing techniques it was reported that extrusion cooking has low cost of production with little energy consumption, high versatility and production output with minimum time and nutrient retention ability as well as bioavailability of bioactive compounds. The work intends to review from past studies the production of innovative, sustainable and diverse food products. The review highlights the mechanisms of operation of extruders, types of extruders, extrusion cooking ingredients, variables and extrusion cooking applications in food.