Granules structure

There are five prime factors that determine the properties of starches 1. starch is a polymer of glucose (dextrose) 2. the starch polymer is of two types linear and branched 3 the linear polymeric molecules can associate with each other giving insolubility in water 4. the polymeric molecules are organized and packed into granules which are insoluble in water and 5 disruption of the granule structure is required to render the starch polymer dispersible in water. The modification of starch takes into account these factors. 

Recently, a cell culture derived from biopsies of healthy human buccal mucosa has been developed with remarkably similar morphology, membranecoating granule structure and appearance, and lipid composition to intact buccal tissue [102], The barrier nature of this cell culture model is similar to intact buccal mucosa, and so this cell culture may be an alternative model to the... 

Maltese cross (Blanshard, 1979). The crystallinity of starch is caused essentially by amylopectin pol)Tner interactions (Banks and Greenwood, 1975 Biliaderis, 1998 Donald, 2004 Hizukuri, 1996). An illustration of currently accepted starch granule structure is given in Fig. 5.5. It is believed that the outer branches of amylopectin molecules interact to arrange themselves into "crystallites" forming crystalline lamellae within the granule (Fig. 5.5 Tester et al., 2004). A small number of amylose polymers may also interact with amylopectin crystallites. This hypothetical structure has been derived based on the cluster model of amylopectin (Hizukuri, 1986 Robin et ah, 1974 Fig. 5.1). 

FIGURE 5.5 Schematic diagram of starch granule structure. Adapted from Donald et al. (1997), Starch - Structure and functionality, ISBN 0854047425, with permission from Woodhead Publishing Ltd., Cambridge, UK. 

Blanshard, J. M. V. (1987). Starch granule structure and function A physicochemical approach. In "Starch Properties and Potential" (T. Galliard, ed.), pp. 16-54. John Wiley and Sons, Chichester. 

Jane, J.-L. (2006). Current understanding on starch granule structure. /. Appl. Glycosci. 53, 205-213. 

Jenkins, P. J., and Donald, A. M. (1995). The influence of amylose on starch granule structure. International Journal of Biological Macromolecules. 17,315-321. 

Oates, C. G. (1997). Towards and understanding of starch granule structure and hydrolysis. 

Buleon, A., Colonna, R, Planchot, V, and Ball, S. 1998. Starch granules Structure and biosynthesis. Int. J. Biol. Macromol. 23 85-112. 

Morrison, W. R. (1995). Stareh lipids and how they relate to starch granule structure and functionality. Cereal Foods World, 40, 437 46. 

Figure 10.6 Effects of hydroxypropylation on the granule morphology of potato starches, (a) Potato starch granules after hydroxypropylation (at 10% propylene oxide concentration), (b) Effect of increased concentration of propylene oxide (15%) on the starch granule structure (source Kaur et al., 2004).

Surface Detail and Inner Granule Structure Revealed by AFM. 173... 

Interpretation of AFM Images with Respect to Granule Structure. 175... 

V. A Hypothesis of Starch Granule Structure The Blocklets Concept.. 180... 

As this chapter and Chapter 6 are read it should be remembered that, as far as is known, the amylose and amylopectin molecules, the granule structure, and the natures and amounts of the lipid and protein molecules present in granules vary with the botanical source of the starch, i.e. are unique to each type of starch. Therefore, what has been... 

---