2025 Volume 58 Issue 1 Pages 7-15
The effects of high pH on the physical properties of cornstarch were studied using steady-shear viscosity and dynamic viscoelasticity measurements, differential scanning calorimetry, microscopic observation, reducing sugar measurements, and color difference measurements. The pH was adjusted using buffered solutions.
The viscoelasticity of 3.00 wt% cornstarch pastes was not affected by alkaline pH up to 12. The gelatinization temperatures and enthalpy of 20 wt% cornstarch also remained unchanged. However, amylose and amylopectin chains were hydrolyzed at pH>9, and starch granules ruptured at pH>11. Cornstarch gelatinization was promoted by strong alkalinity at pH>12, and cornstarch paste viscoelasticity increased at 12.0<pH<13.1. In contrast, many amylose and amylopectin chains were hydrolyzed at the stronger pHs(pH>13.1), decreasing cornstarch paste viscoelasticity.
