High-solids gel properties of acid-hydrolyzed waxy maize starch are determined by the molecular-weight distribution

This study aimed to understand the effect of molecular-weight distribution on the properties of acid-hydrolyzed waxy maize starches (AH-WMSs) prepared at different acid concentrations and hydrolysis times at 50 °C. A reduction in molecular weight of AH-WMS resulted in increased paste fluidity and light transmittance, as well as decreased sedimentation, amylose‑iodine complex, and pasting viscosity. Freshly prepared AH-WMS viscoelastic gels at 20 % solids showed thixotropy at 25 °C and 50 °C, and both the shear stress and the area of hysteresis loop decreased with decreasing molecular weights. After storage at 4 °C for 24 h, the AH-WMS viscoelastic gels exhibited anti-thixotropy at 25 °C. However, the anti-thixotropy behavior disappeared at 50 °C for those with lower molecular weights. Freshly prepared viscoelastic gels obtained from AH-WMSs with higher molecular weights showed higher values of liquidity, firmness, consistency, cohesiveness, and viscosity at 20 % and 30 % solids. After storage at 4 °C for 24 h, AH-WMS viscoelastic gels at 30 % solids transformed into solid gels, and the gel strength decreased with decreasing molecular weights. AH-WMSs with a similar molecular-weight distribution displayed similar pasting, rheological, and textural properties at high solids.