The recent review and relevant paper informed that high temperature treatment of cereals at given water content reduced the content of mycotoxins or detoxified them to a certain extent. This heat treatment system should have the high through put and quick, homogeneous and continuous functions toward the practical use in food processing. These requirements turn our interest on to Extrusion Cooking due to its high applicability.
Food extrusion is considered a high-temperature short-time reactor that transforms a variety of raw ingredients into modified intermediate and finished products. The impetus for these developments has been the following requirements of food processing: 1) continuous high-throughput processing, 2) energy efficiency, 3) relatively dry or wet materials and 4) control of thermal changes of material constituents.
Single-screw extruders were developed in the 1940s and its further refinement occurred during the 1970s. The use of twin-screw extruders started in the same period, with an expanding application in the 1980s. Although twin-screw extruders come in a variety of designed, the co-rotating, intermeshing screw type has found the widest acceptance. This type shows improved conveying and mixing abilities, self-wiping function and interchangeable screw profiles and expands operational capabilities and application.
This paper will cover the basic structure of single- and twin-screw extruder and compare their characteristics and provide some information on the change of food main components such as starch and protein.
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