Starch

Starch granules are mainly found in seeds, roots, and tubers. The organization of starch components (amylose and amylopectin) as well as the presence of minor constituents (lipids, phosphate ester groups, and proteins) in the granules depends on botanical source, and they determine the functionality and end-use of starch. A comprehension of granular internal organization of starch components gives information to understand starch functionality and its behavior during processing. These polysaccharides can be isolated employing several methodologies, which mainly rely on the starch origin. In general, these methods include milling (wet or dry), gravity sedimentation, centrifugation, and filtration steps. In this chapter, the organization of starch components in the granule and the diverse isolation methods from different botanical sources are described. Besides, functional and physicochemical properties of several native starches, such as pasting and thermal properties are mentioned. Usually, native starches present inappropriate characteristics for most industrial applications and, hence, they must be modified by chemical and/or physical methods in order to broad their usage possibilities. Thus, in this section, several methodologies used to modify starches are described and the properties of the obtained derivatives are also reported.