Abstract: This paper reports on the effect of adding different amounts (2%, 6% and 10%) of maltose to proso millet starch, waxy rice starch and waxy corn starch on their gelatinization and rheological properties as determined using a rapid viscosity analyzer (RVA), a rheometer, differential scanning calorimetry (DSC) and low-field strength nuclear magnetic resonance (LF-NMR). The results showed that maltose could increase the pasting temperature of the three waxy cereal starches and reduce the peak viscosity, final viscosity and setback value. The shear stress and consistency of starch paste decrease with maltose addition, but the pseudoplasticity remained unchanged. Addition of 10% maltose had a greater influence on waxy corn starch than on proso millet starch and waxy rice starch, decreasing the consistency coefficient K value from 32.546 to 4.801 Pa·sn and giving rise to a more obvious shear thinning phenomenon. Thermodynamic studies showed that addition of maltose could increase the gelatinization temperature and gelatinization enthalpy value of the three waxy cereal starches in a concentration-dependent manner. Low-field nuclear magnetic resonance revealed that addition of maltose increased the content of bound water and immobile water in the entire system, and reduced the content of free water, which further explains its ability to reduce the viscosity of the system and increase starch gelatinization temperature. The results of this study can guide the application of maltose in waxy cereal foods.

Key words: waxy cereal starch; maltose; gelatinization properties; rheological properties