Structural, rheological and in-vitro digestibility properties of composite corn-banana starch custard paste

- Structural and in-vitro digestibility properties of corn-banana starch composite custard pastes were investigated.
- Banana starch was incorporated as native, heat moisture treated or annealed starch at 25% inclusion ratio in the composite.
- Micrographs showed similar homogenous, non-continuous, flake-like network structure for all paste samples.
- Hydrothermal modifications significantly (p < 0.05) increased the resistant starch component of the pastes.

This study investigated the influence of native or hydrothermally modified banana starch on structural, rheological and in-vitro digestibility properties of corn starch custard pastes. Banana starch was incorporated into the formulation in the ratio 1:4 (g/g) of the composite. Amylose content in the pastes varied significantly (p < 0.05) from 17.61 to 27.27 g/100 g. Scanning electron micrographs revealed similar homogenous, non-continuous, flake-like network structure for all paste samples. Addition of modified banana starch generally reduced the strength of the pastes. Generally, the paste samples showed shear thinning behavior of thermoplastic materials. Banana starch inclusion in the custard formulation significantly (p < 0.05) increased the slowly digestible starch fraction of the pastes, while the addition of annealed or heat moisture treated banana starch significantly (p < 0.05) increased the resistant starch component.