The Impact of Basil Seed Gum on Native and Pregelatinized Corn Flour and Starch Gel Properties

Abstract

The effect of Basil Seed Gum (BSG) on native and pre-gelatinized corn starch and flour gels was evaluated. With this purpose, the hydration, pasting, rheological, textural and microstructural properties of the mixed gels were analyzed. Xanthan was used as a comparison, as it presents comparable high zero shear viscosity to BSG. The presence of BSG led to greater water binding capacity and greater water absorption index of the starch and flours compared to the free-gum systems. In general BSG substantially increased the peak and final viscosities of the pastes, also leading to a raise in the viscoelasticity (G’ and G”) and hardness of the final gels, native or treated (pregelatinized starch and extruded flour). A more opened microstructure—compared to a homogeneous and dense matrix of the control native starch gels— with strands and a spider-like network of BSG across the pockets was detected. On the other hand, xanthan showed the opposite effect, decreasing the peak and final viscosities of the native systems, delaying the gelatinization process, and also leading to weaker gels of reduced viscoelasticity with opened honeycomb-like microstructures. However, for pregelatinized flour and starch the effect of xanthan was minimal.