Interactions of native and acetylated pea starch with yellow mustard mucilage, locust bean gum and gelatin

Abstract

The interactions of yellow mustard mucilage, locust bean gum and gelatin with native and acetylated pea starch were studied by a Brabender viscograph, a Bohlin rheometer and differential scanning calorimetry (DSC). In the presence of mustard mucilage or locust bean gum, the onset temperature of the viscogram shifted to lower temperatures, whereas the final viscosities of the pastes increased markedly for both native and modified pea starch. Gelatin produced only a slight increase in the viscosity of native pea starch, whereas the viscosity of modified pea starch in the presence of gelatin decreased. DSC studies demonstrated that the presence of a hydrocolloid did not change the gelatinization temperature of pea starch. The variation in the viscosity onset temperature, as observed with Brabender, was attributed to an increase in the medium viscosity of a starch/hydrocolloid dispersion. The increase in starch paste viscosity was due to synergistic interactions of starch and gums. Pea starch pastes exhibited the typical shear thinning behaviour and the addition of a hydrocolloid altered the degree of pseudoplasticity of a starch paste. Mustard mucilage, for example, increased the pseudoplasticity of pea starch pastes, and exhibited higher paste viscosities at low shear rates.