Starch Thermal Processing: Technologies at Laboratory and Semi-Industrial Scales

Multilevel structure and multiphase thermal transition of starch make its processing much more complex than that of synthetic polymers. This chapter discusses the unique structure and phase transition of native starch, as well as rheological properties of starch during thermal processing. The techniques used to study these characteristics are described. However, although starch can be processed using the conventional techniques designed for synthetic polymers, these techniques should be adapted along with optimized operational conditions and formulations. Regarding this, this chapter summarizes various processing techniques at laboratory and semi-industrial scales such as solution casting, extrusion, injection and compression moldings, as well as other innovative methods such as reactive extrusion. In particular, the most important aspects of starch processing pertaining to the use of plasticizers, blending with other polymers or ingredients, and orientation are discussed. Accordingly, native starch can be processed into different forms of plastic product such as films/sheets, foams and shaped articles for food packaging and other niche applications.