Research of rheological properties of egg sponge with extruded corn flour

Abstract

Addition of extruded corn flour affects the egg sponge stability. The dependence of the effective viscosity of egg sponge samples with different concentrations of extruded corn flour on the shear rate and stress is investigated. Viscosity index is closely associated with the water-retaining capacity of the egg sponge. So, there is a need to study the state of free and bound water in the egg sponge depending on the content of extruded corn flour. The aim of the research was to identify the impact of extruded corn flour on the rheological properties of the egg sponge under mechanical impact, and study of the effect of extruded corn flour addition on the ratio of the state of free and bound water in it. The most intensive decrease in viscosity with increasing shear rate is observed in the sponge based on the mixture with the content of extruded corn flour of 50 % at a shear rate of 2.4 s -1 . Further decrease in effective viscosity with increasing shear rate is less intense, and all the samples tend to approach a constant viscosity of 2.4 Pa•s for the control sample and the viscosity of 4.2 Pa•s in the sample with the content of extruded corn flour of 50 % at a shear rate of γ 11.65 s -1 . Increased amount of extruded corn flour raises the spin-spin relaxation time, indicating a decrease in the mobility of water molecules in solution. This suggests that increased amount of extruded corn flour in the egg sponge increases the amount of bound water, which contributes to retaining more moisture in the finished product. The research shows the feasibility of extruded corn flour in the technology of semi-finished sponge cake that will improve the quality indicators of the finished product and extend its life.