Impact of amylose content on the formation of V-type granular starch

V-type granular starch (VGS) was prepared by aqueous-ethanol heat treatment using normal maize starch (NMS) with an amylose content of 31.02% (NMS1), 25.08% (NMS2), or 22.39% (NMS3). The effects of different amylose contents on VGS granular morphology, crystalline structure, thermal transitions, and cold-water paste viscosity properties were compared. Moreover, the effects of different temperature holding times (0–30 min) during aqueous-ethanol heat treatment on the formation of VGS were evaluated. The results showed that NMS1, for which the amylose content was the highest, required 5 min holding at 100 °C to reach the maximum V-type relative crystallinity (13.97%) and the highest cold-water paste viscosity (2981.28 cP) while maintaining the most intact granular morphology. Longer temperature holding periods caused damage to starch granules and decreased the formation of V-type crystals. Higher amylose content was beneficial for preservation of starch granule integrity and the formation of V-type crystals, resulting in a higher cold-water paste viscosity of VGS. However, starch with higher amylose contents required more energy to fully disorder amylose to form V-type complexes with ethanol.