Effects of Soybean Oligopeptides on the Gel Properties of Wheat Starch

To improve the quality of wheat flour and increase the protein content of wheat foods, soybean oligopeptide, which has nutritional value and biological activity, was added to wheat starch. The pasting properties, rheological properties, thermodynamic properties and structural properties of wheat starch were investigated. The results showed that the addition of soybean oligopeptide (0%~40%) decreased the peak viscosity, trough viscosity and final viscosity of the complexes, and increased the pasting temperatures significantly (P<0.05). The complexes exhibited weak gel properties with pseudoplastic shear-thinning behavior. Compared with the control group, the addition of soybean oligopeptide at 40% resulted in the smallest peak viscosity of 396 cp, the largest pasting temperature of 77.5 °C, the decrease in the enthalpy change by 79.6%, the decrease in the absolute value of the zeta-potential by 89.6%, and the increase in the particle size to 924.1 nm. Soybean oligopeptides increased the amino acid content and thermal stability of the complexes and decreased the gel properties of the complexes, providing a reference for the development and processing of functional cereal foods.