Atomic Force Microscopy Investigation of Disorder Process on Rice Starch Granule Surface

Starch - Starke (Impact Factor: 1.68). 09/2006; 58(9):475–479. DOI: 10.1002/star.200500471


Precise ultra-structures of rice starch granules have been analyzed by atomic force microscopy combined with a structure-disorder process at ambient conditions. Atomic force microscopy is a useful technique to obtain images under atmospheric condition with a nanometer-scale resolution. The images obtained by a high-resolution tapping mode revealed a detailed surface ultra-structure of native rice starch granule with a diameter of approximately 100 nm. The ultra-structures were arranged in series like a chain, and the chain was bundled together into a rod or larger column. After a disorder process using plasticizing/lyophilization of the granules, a significant change in the organization of the surface morphology was detected. Some fine particles of approximately 30 nm in diameter were observed, which might correspond to the individual single cluster in the crystalline region of the starch granule.

Download full-text


Available from: Ali Ayoub, Jun 14, 2015
  • Source
    • "On the opposite limit of size scale, namely the sub-granule details , neither optical microscopy nor SEM can provide enough contrast to resolve features (BeMiller and Whistler, 2009; Singh et al., 2003; Cornuéjols and Pérez, 2010; Szymon´ska et al., 2009; Seetharaman and Bertoft, 2012). However, in recent years AFM has appeared as the most promising technique for resolving granule substructures (Juszczak et al., 2003; Ohtani et al., 2000; An et al., 2008; Baldwin et al., 1997, 1998; Park et al., 2011; Ridout et al., 2002, 2003; Szymon´ska and Krok, 2003; Tang and Copeland 2007; Ayoub et al., 2006; Sujka and Jerzy, 2009). For example, in Fig. 2 some similar features appear. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We studied the nano-scale properties of dry native starch granules of wheat and potato by atomic force microscopy. Whereas at the macroscale the mechanical behavior of starch powders is known, its origin at sub-granule level has still to be understood. We observed fine morphological structures, such as the growth rings and blocklet domains, with minor differences between the two starches. The granules, embedded in resins with known stiffness, were analyzed with lateral-force, force-distance and force-modulation microscopy. Integer granules exhibited a similar friction coefficient to the tip, decreased with respect to the embedding resin, without occurrence of stick-slip. The compressive modulus measured was also similar for both starch types (∼1.4 GPa in indentation and ∼2.0 GPa in dynamic mode), with slightly higher values for potato starch. On sectioned granules, the effect of aging in air likely due to moisture produced in both starches a strong reduction in apparent modulus (∼0.2 GPa).
    Full-text · Article · May 2014 · Journal of Food Engineering
  • Source
    • "In contrast, atomic force microscopy (AFM) enables high-resolution (< 1 nm) 3D imaging of biological surfaces in atmospheric and even aqueous conditions and does not require the samples to be metal coated (Gallant et al. 1997, Ohtani et al. 2000). The exterior (Gallant et al. 1997) and interior surfaces (Baker et al. 2001, Juszczak 2003) of starch granules from various food crops have been investigated (Baldwin et al. 1998, Ohtani et al. 2000, Ridout et al. 2002, Kim et al. 2005, Ayoub et al. 2006, Dang et al. 2006), but there have been few studies on starch granules in conifer needles. Although TEM has been used to examine the histochemistry (Lepedus et al. 2005) and stress responses of plants (Utriainen et al. 2000, Kivimäenpää et al. 2001), these studies were made on cross sections of needle segments, a time consuming and impractical procedure for assessing large numbers of samples. "
    [Show abstract] [Hide abstract]
    ABSTRACT: We compared the effects of ambient (350 ppm) and elevated CO(2) concentration (700 ppm) on the size and shape of starch granules in Norway spruce (Picea abies (L.) Karst.) needles during one growing season. Starch granules were isolated from needles by alkaline digestion and analyzed by transmission electron microscopy (TEM) and atomic force microscopy (AFM). Measurements made with a particle size analyzer indicated that starch granules ranged between 0.5 and 10 microm. Granule size and shape varied according to needle developmental stage and CO(2) concentration. Generally, elevated CO(2) concentration increased the size of the starch granules. Fine surface structures (< 10 nm in size) studied by AFM were characterized by the presence of protrusions, furrows and pores.
    Full-text · Article · Oct 2008 · Tree Physiology
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The effect of alkaline treatment on the ultrastructure of C-type starch granules was investigated during the alkaline extraction of Araucaria angustifolia (pinhao) starch. The efficiency in protein removal was evaluated using intrinsic fluorescence and Kjeldahl's method. In parallel, morphological changes of starch granules were observed using scanning electron microscopy and atomic force microscopy. The starch crystallinity was monitored by wide-angle X-ray scattering and the lamellar structure was studied by small-angle X-ray scattering (SAXS). The paracrystalline model was employed to interpret the SAXS curves. It was found that the granular organization was significantly altered when alkaline solutions were used during the extraction. A partial degradation of B-type allomorph of starch and a significant compression of semicrystalline growth rings were observed.
    Full-text · Article · Aug 2008 · Biomacromolecules
Show more