TY - JOUR
T1 - Effects of processing high amylose maize starches under controlled conditions on structural organisation and amylase digestibility
AU - Htoon, A.
AU - Shrestha, A. K.
AU - Flanagan, B. M.
AU - Lopez-Rubio, A.
AU - Bird, A. R.
AU - Gilbert, E. P.
AU - Gidley, M. J.
PY - 2009
Y1 - 2009
N2 - 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 α-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.
AB - 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 α-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.
UR - http://handle.westernsydney.edu.au:8081/1959.7/uws:17830
U2 - 10.1016/j.carbpol.2008.06.016
DO - 10.1016/j.carbpol.2008.06.016
M3 - Article
SN - 0144-8617
VL - 75
SP - 236
EP - 245
JO - Carbohydrate Polymers
JF - Carbohydrate Polymers
IS - 2
ER -