Effects of processing high amylose maize starches under controlled conditions on structural organisation and amylase digestibility
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The amylase digestibility of high-amylose maize starches has been compared before and after thermo-mechanical processing. Starches were analysed for enzyme-resistant starch yield, apparent amylose content, crystallinity (X-ray diffraction), and molecular order (NMR and FTIR), both before and after treatment with (x-amylase. All samples had significant (>10%) enzyme-resistant starch levels irrespective of the type and extent of thermal or enzymic processing. Molecular or crystalline order was not a pre-requisite for enzyme resistance. Near-amorphous forms of high amylose maize starches are likely to undergo recrystallisation during the enzyme-digestion process. The mechanism of enzyme resistance of granular high-amylose starches is found to be qualitatively different to that for processed high-amylose starches. For all samples, measured levels of enzyme resistance are due to the interruption of a slow digestion process, rather than the presence of completely indigestible material. © 2008, Elsevier Ltd.
Starch, Amylase, Maize, Fourier transformation, Digestion, Extrusion
Htoon, A., Shrestha, A. K., Flanagan, B. M., Lopez-Rubio, A., Bird, A. R., Gilbert, E. P., & Gidley, M. J. (2009). Effects of processing high amylose maize starches under controlled conditions on structural organisation and amylase digestibility. Carbohydrate Polymers, 75(2), 236-245. doi:10.1016/j.carbpol.2008.06.016