312 Bulletin UASVM Agriculture, 69(2)/2012 Print ISSN 1843-5246; Electronic ISSN 1843-5386 Aspects of Thermoplastic Extrusion in Food Processing Mircea-Valentin MUNTEAN, Ioan DROCAS, Ovidiu MARIAN, Victor BARBIERU, Ovidiu RANTA University of Agricultural Sciences and Veterinary Medicine, Faculty of Agriculture, 3-5 Manastur street, Cluj Napoca, Romania; mmvali@yahoo.com Abstract. The extrusion screw process is used in food and agricultural industries to make a variety of products and combines a several unit operations including mixing, cooking, kneading, shearing, sheaping and forming. The process can be used to make different types of products like cereal-based products, sugar-based products and protein-based products. Keywords: single-screw extruder, twin-screw extruder, temperature, flow, extruded equipment, process modeling INTRODUCTION Extrusion is a process in wich material is pushed trough an orifice or a die of given shape. The pushing force is applied using single or twin-screw extruder. Extrusion processing of food materials has become an increasingly important manufacturing method, and its application have broadened substantially in the last two decades (Karwe M.V., Food extrusion vol. III). The principles of operation are similar in all types: raw materials are feed into the extruder barrel and screw(s) pushed toward die and cutter. From transport phenomenon, extrusion process can be a combination of several processes such fluid flow, heat and mass transfer, mixing, shearing, particule size reduction, melting, texturizing, caramelizing, shaping and forming of different types of product (Karwe M.V., Food Process Engineering). Depending of the product, one or many of these processes will take place in an extruder. A variety of products such as breakfast cereals, pasta, snack products, candy, pet foods are made using screw extrusion processes. Extrusion is a continuous process, it’s flexible because on-line process adjustments can be made to achieve desired product characteristics. There are many advantages of extrusion processing comparative with conventional cooking processes. On the other side, the same extruder can be used to make different types of products. Better process control strategies have to control the thermo-mechanical changes during extrusion to achieve desired product properties. The popularity of extrusion technologies are increase in last two decades because of the following reasons: can obtain a wide range of products that do not come easily with other technologies but by replacing components can be obtained by extrusion; extrusion cost operation has lower and higher productivity than other heating and forming processes; extrusion operation involves high temperature applied for a short time retaining many heat sensitive components of a food; costs of extrusion operation are lower than other operations like heating and forming processes in food industry; faster time processing reduce energy consumption. brought to you by CORE View metadata, citation and similar papers at core.ac.uk