TY - JOUR
T1 - Structural changes of debranched corn starch by aqueous heating and stirring
AU - Han, J. A.
AU - BeMiller, J. N.
AU - Hamaker, B.
AU - Lim, S. T.
PY - 2003
Y1 - 2003
N2 - Aqueous dispersions (2 mg/mL) of debranched corn starches of different amylose contents (waxy, normal, and high-amylose) were subjected to extensive autoclaving and boiling-stirring, and then the changes in starch chain profile were examined using medium-pressure, aqueous, size-exclusion column chromatography. As autoclaving time increased from 15 to 60 min, weight-average chain length (CLw) of waxy, normal, and high-amylose corn starches determined using pullulan standards decreased from 46 to 41.2, from 122.1 to 96.3, and from 207.3 to 151.8, respectively. Number-average chain length (CLn) measured by the Nelson-Somogyi method also decreased from 23.0 to 18.4, from 26.4 to 21.8, and from 66.5 to 41.5, respectively, indicating that thermal degradation of starch chains occurred. The CLw/CLn ratio for normal corn starch was higher than that for waxy corn starch, indicating an increase in polydispersity of the amylose fraction. Thermal degradation was also observed when the debranched starch was subjected to the boiling-stirring treatment (0-96 hr). During 96 hr, the CLw and relative proportion of B≥2 chains of amylopectin released by debranching waxy corn starch increased, whereas those of B1 chains decreased. This change may indicate physical aggregation of B1 chains. But branches from normal and high-amylose corn starches showed increases in CLw and the proportion of both B1 and B≥2 chains, along with substantial decreases in those of amylose chains. Therefore, thermal degradation of amylose was greater than that of amylopectin.
AB - Aqueous dispersions (2 mg/mL) of debranched corn starches of different amylose contents (waxy, normal, and high-amylose) were subjected to extensive autoclaving and boiling-stirring, and then the changes in starch chain profile were examined using medium-pressure, aqueous, size-exclusion column chromatography. As autoclaving time increased from 15 to 60 min, weight-average chain length (CLw) of waxy, normal, and high-amylose corn starches determined using pullulan standards decreased from 46 to 41.2, from 122.1 to 96.3, and from 207.3 to 151.8, respectively. Number-average chain length (CLn) measured by the Nelson-Somogyi method also decreased from 23.0 to 18.4, from 26.4 to 21.8, and from 66.5 to 41.5, respectively, indicating that thermal degradation of starch chains occurred. The CLw/CLn ratio for normal corn starch was higher than that for waxy corn starch, indicating an increase in polydispersity of the amylose fraction. Thermal degradation was also observed when the debranched starch was subjected to the boiling-stirring treatment (0-96 hr). During 96 hr, the CLw and relative proportion of B≥2 chains of amylopectin released by debranching waxy corn starch increased, whereas those of B1 chains decreased. This change may indicate physical aggregation of B1 chains. But branches from normal and high-amylose corn starches showed increases in CLw and the proportion of both B1 and B≥2 chains, along with substantial decreases in those of amylose chains. Therefore, thermal degradation of amylose was greater than that of amylopectin.
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U2 - 10.1094/CCHEM.2003.80.3.323
DO - 10.1094/CCHEM.2003.80.3.323
M3 - Article
AN - SCOPUS:0037646064
VL - 80
SP - 323
EP - 328
JO - Cereal Chemistry
JF - Cereal Chemistry
SN - 0009-0352
IS - 3
ER -