Compositions of Starch Granules

Chapter 6. Besides strengthening the coverage on dissolved-polymer gels, a section was added on theoretical treatment of starch gels as composites of starch granules in an amylose matrix. 

Intrinsic factors that may influence potato digestibility include the structure of the starch molecules, the structure of starch granules, the composition of the potato, the presence of phosphate in starch granules, tissue structure, and factors that may affect these, including agronomic and growth history, storage, maturity, and variety. 

Storage Polysaccharides. Starch and Starch Derivatives. Amylose and amlyopectin are the major components of starch granules found in food reserves of all green plants. Commercial starch is obtained from sources such as com, sorghum, rice, wheat, and potatoes. The compositions of the amylose and amy-lopectin vary with source. 

The addition of starch has a nucleating effect which increases the crystallisation rate of the polyester [92]. The rheology of the starch/PCT blends depends on the extent of starch granule destruction and the formation of thermoplastic starch during extrusion. Increasing shear and heat intensities can reduce the melt viscosity, but enhance the extrudate swelling properties of the composite [94]. 

Fig. 4 (Miller)—Different types of starch granule, a, from the haricot bean B, from maize C and Cl, from potatoes (c, simple granule Ci, composite granule) D and D, rice grains (d, whole of the composite grain D, one of the constituents of the grain at a higher magnification) E, wheat grain f, composite grain from oats. Note that each elementary granule (a. b, C, c, d, e) has a number of concentric striations around an initial point,...

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