ABSTRACT
Starch, a glucose polymer, is one of the most abundant natural polysaccharides synthesized by plants. Corn, potato, wheat, rice, cassava (tapioca), and sorghum are the major botanical sources for most commercial starches. Table 2.1 lists the major crop sources of starch worldwide. In its native state, starch is produced in granular form in plant cells mostly located in fruits, grains, and roots/tubers which is recovered during commercial processing and reŠning (Eksteen et al. 2003; Rausch and Belyea 2006). The United States is the largest producer of starch in the world and contributes about half of the commercial starch produced globally. Roughly, 6.5 billion pounds of cornstarch and specialty corn chemicals are produced every year in the United States (www.faostat. fao.org). Many streams of industrially useful chemicals and by-products are also produced during the commercial processing of corn (Kim et al. 2008). These include protein, corn Šber, C5 and C6
CONTENTS
2.1 Introduction ..............................................................................................................................5 2.2 Starch Chemistry and Properties ..............................................................................................7 2.3 Starch Morphology and Microstructure ................................................................................. 13 2.4 Starch-Hydrolyzing Enzymes ................................................................................................. 19
2.4.1 Starch Depolymerases ................................................................................................20 2.5 Extrusion Processing of Starch and Starch-Based Bioplastics ...............................................22
