Effect of enzymatic hydrolysis on native starch granule structure

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dc.contributor.authorGilbert, EPen_AU
dc.contributor.authorBlazek, Jen_AU
dc.date.accessioned2011-08-17T02:54:23Zen_AU
dc.date.available2011-08-17T02:54:23Zen_AU
dc.date.issued2010-12-13en_AU
dc.date.statistics2011-08-17en_AU
dc.description.abstractEnzymatic digestion of six starches of different botanical origin was studied in real time by in situ time-resolved small-angle neutron scattering (SANS) and complemented by the analysis of native and digested material by X-ray diffraction, differential scanning calorimetry, small-angle X-ray scattering, and scanning electron microscopy with the aim of following changes in starch granule nanostructure during enzymatic digestion. This range of techniques enables coverage over five orders of length-scale, as is necessary for this hierarchically structured material. Starches studied varied in their digestibility and displayed structural differences in the course of enzymatic digestion. The use of time-resolved SANS showed that solvent-drying of digested residues does not induce any structural artifacts on the length scale followed by small-angle scattering. In the course of digestion, the lamellar peak intensity gradually decreased and low-q scattering increased. These trends were more substantial for A-type than for B-type starches. These observations were explained by preferential digestion of the amorphous growth rings. Hydrolysis of the semicrystalline growth rings was explained on the basis of a liquid-crystalline model for starch considering differences between A-type and B-type starches in the length and rigidity of amylopectin spacers and branches. As evidenced by differing morphologies of enzymatic attack among varieties, the existence of granular pores and channels and physical penetrability of the amorphous growth ring affect the accessibility of the enzyme to the substrate. The combined effects of the granule microstructure and the nanostructure of the growth rings influence the opportunity of the enzyme to access its substrate; as a consequence, these structures determine the enzymatic digestibility of granular starches more than the absolute physical densities of the amorphous growth rings and amorphous and crystalline regions of the semicrystalline growth rings. © 2011, American Chemical Society.en_AU
dc.identifier.citationBlazek, J., Gilbert, E.P. (2010). Effect of enzymatic hydrolysis on native starch granule structure. Biomacromolecules, 11(12), 3275-3289. doi:10.1021/bm101124ten_AU
dc.identifier.govdoc3435en_AU
dc.identifier.issn1525-7797en_AU
dc.identifier.issue12en_AU
dc.identifier.journaltitleBiomacromoleculesen_AU
dc.identifier.pagination3275-3289en_AU
dc.identifier.urihttp://dx.doi.org/10.1021/bm101124ten_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/3697en_AU
dc.identifier.volume11en_AU
dc.language.isoenen_AU
dc.publisherAmerican Chemical Societyen_AU
dc.subjectEnzymatic hydrolysisen_AU
dc.subjectStarchen_AU
dc.subjectX-ray diffractionen_AU
dc.subjectNeutronsen_AU
dc.subjectGelatinen_AU
dc.subjectCrystallizationen_AU
dc.titleEffect of enzymatic hydrolysis on native starch granule structureen_AU
dc.typeJournal Articleen_AU
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