Improved the slow digestion property of maize starch using partially β-amylolysis

In this study, partial β-amylolysis was used to modulate the starch fine structure responsible for the slow digestion property of starch. Normal maize starch modified using β-amylase for 2 h showed an increase of slowly digestible starch from 11.16% to 24.38%. The β-amylase treatment increased the amylose content from 28.4% to 32.5%, decreased the molecular weight from 32.5 × 107 to 3.8 × 105 g/mol and increased the number of shorter chains (DP < 13) from 25.5% to 41.1%, accompanied by a reduction of longer chains (DP > 13). 1H NMR spectra showed an increase of α-1,6 linkages from 7.4% to 10.1% in the enzyme treated starches. Both the increase in the amount of shorter chains and the increase in α-1,6 linkages were attributed to the slow digestion property of starch. These results suggest that starches treated with partial β-amylolysis retain a branched structure and slow digestibility.