Starch occurrence

Thus, based on material applications, the following polymers are important natural rubber, coal, asphaltenes (bitumens), cellulose, chitin, starch, lignin, humus, shellac, amber, and certain proteins. Figure 4 shows the primary structures of some of the above polymers. For detailed information on their occurrence, conventional utilization, etc., refer to the references cited previously. 

One of the most abundant biopolymers available in nature is starch. Starch is a polysaccharide consistent of glucose monomers and is found in all green plants. Next to its occurrence in food and its use in food-related industries, the major application of starch is in the paper industry, followed by the adhesives industry. 

Figure 5.15 Scanning electron micrographs of starch granules after mild a-amylolysis showing the occurrence of spherical bl ocklet-l I ke structures, (a) potato and (b) wheat starch granules. (Adapted with permission from reference 1)...

Starch gelatinization—a unimolecular occurrence—follows pseudo-first-order kinetics after an initial time lag (Okechukwu and Rao, 1996a). 

The /3-amylase liberates the maltose in the /S-configuration. This is no proof for the occurrence of /3-D-glucosidic linkages in starch. On the other hand, it is not known why the /3-amylase, in contrast to the a-amylases, causes an inversion of the configuration. 

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