Production of boiling-stable granular resistant starch by partial acid hydrolysis and hydrothermal treatments of high-amylose maize starch

The purpose of the present work was to examine whether partial acid hydrolysis (PAM of a high-amylose maize starch (ae-VII) would enhance the effects of hydrothermal treatments to produce granular resistant starch (RS) that is stable to further heat treatment at atmospheric pressure. PAH ae-VII starches were prepared by heating 35% (w/v) suspensions with 1% (w/w) HCl at 25 degreesC for 6, 30, and 78 hr. Native and PAH starches were then treated by annealing (ANN) or heat-moisture treatment (HMT). ANN was done at 70% moisture at 50, 60, or 70 degreesC for 24 hr, and HMT was done at 30% moisture at 100, 120, or 140 degreesC for 80 min. RS that survives boiling during analysis was determined by a modification of the AOAC method for determining total dietary fiber. RS was also determined by the Englyst method. Little change in the gelatinization enthalpy was found for ae-VII starch after PAH, ANN, or HMT as individual treatments. After PAH, either ANN or MAT led to decreased gelatinization enthalpy. HMT and ANN alone increased boiling-stable RS but decreased total RS. After PAH of ae-VII, either ANN or HMT tended to increase the yield of boiling-stable granular RS, with the greatest yield (less than or equal to 63.2%) observed for HMT.