The amylopectin molecular structures and functional properties of different-sized fractions of normal
and high-amylose maize starches were investigated and compared in this study. The different-sized
fractions of normal starch showed similar amylopectin molecular structures and functional properties.
The small-sized fraction of high-amylose starch had significantly higher amylopectin long branch-chain
and average branch-chain length than its counterpart medium- and large-sized fractions. The swelling
power, gelatinization enthalpy, and hydrolysis and digestion degrees of high-amylose starch significantly
decreased with decrease of granule size, and were significantly positively correlated with amylopectin
short branch-chain and negatively correlated with amylopectin long branch-chain and average branchchain
length. The gelatinization peak temperature and resistant starch content increased with decrease
of granule size, and were significantly positively correlated with amylopectin long branch-chain and
average branch-chain length and negatively correlated with amylopectin short branch-chain. The hierarchical
cluster analysis indicated that the large-sized fraction of high-amylose starch was significantly
different from the medium- and small-sized fractions of high-amylose starch but more relative with
normal starch. The above results could provide important information for the applications of differentsized
fractions of high-amylose maize starch.