Potato starch granule surfaces

Figure 5.18 (a) LVSEM micrograph of a typical potato starch granule surface region (magnification... 

Figure 10.3 Scanning electron micrographs (SEM) featuring (a) the presence of some small size nodules or protuberances on some potato starch granules and (b) surface fragmentation on some potato starch granules (source Singh et al., 2006).

Figure 5.19 (a) AFM image of a typical surface region of a potato starch granule (scan size 1000nm2,... 

Another method used for starch is the non-contact mode, where the starch granules are simply spread onto an adhesive tape fixed on the AFM sample holder. Using this technique, both nodules (20-50 nm in diameter) and smooth areas without any visible features were observed at the surface of potato starch granules.114 Multiple freeze-thaw cycles have revealed an internal, lamellar structure of chain clusters bundled into blocklets 50-300 nm in diameter.115... 

Krok, F., Szymonska, J., Tomasik, P., et al. (2000). Non-contact AFM Investigation of Influence of Freezing Process on the Surface Structure of Potato Starch Granule. 

Juszczak, L., Fortuna, T. Krok, F. (2003). Non-contact Atomic Force Microscopy of Starch Granules Surface, Part I Potato and Tapioca Starches. Starch, 55,1-7. 

Potato starch source Small granules (%) (1-10 p,m) Medium granules (%) (11-25 (xm) Large granules (%) (>25 p,m) Mean volume (p.m ) Specific surface area (mVg)... 

Modification, which involves the alteration of the physical and chemical characteristics of the native potato starch to improve its fimctional characteristics, can be used to tailor it to specific food applications. The rate and efficacy of any starch modification process depend on the botanical origin of the starch and on the size and structure of its granules. This also includes the surface structure of the granules, which encompasses the outer and iimer surface depending on the pores and channels, which cause the development of the so-called specific surface (Juszczak, 2003). Potato starch modification can be achieved in three different ways physical, conversion, and chemical (derivatization) (Table 10.6). 

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