Preparation of starches with low glycaemic response using amylosucrase and their physicochemical properties

Enzymatic modification by amylosucrase (AS) from Neisseria polysaccharea was used on waxy rice, normal rice, waxy corn, normal corn, waxy potato, and normal potato starches to prepare the starches with a high content of slowly digestible starch (SDS) fraction. The AS-treated starches contained similar amounts of resistant starch, decreased rapidly digestible starch, and increased SDS compared to controls. After the AS treatment, the SDS contents increased by approximately 25% in waxy starches but about 8% in normal starches. The yields of the insoluble fraction of waxy starches were about 15% higher than those of normal starches. The branch chain length was increased by DP 13–19. The AS-treated starches showed a B-type X-ray diffraction pattern, 5–9 J/g for retrogradation enthalpy, 88–89 °C for peak temperature, and much larger moduli for their gels compared with raw starches.