Swelling-solubility characteristics, granule size distribution and rheological behavior of banana (Musa paradisiaca) starch

The rheological behavior at 25 and 60 °C together with the pasting properties of banana starch were examined through DSC, Brabender profile, swelling-solubility characteristics, granule size distribution and steady and oscillatory flow of pastes with 1–6% starch. Some of these properties and behaviors were also determined in cornstarch pastes for the purpose of comparison. The temperature of starch gelatinization was 75 °C and pastes were stable to thermal and mechanical treatment. Swelling and solubility were about 14% and 25 g/g, respectively. The median diameter D [v, 0.5] of the uncooked starch was 24.31 μm, while that of cooked starch ranged from 59 to 66 μm depending on starch concentration. The pastes exhibited non-Newtonian shear thinning behavior that could be fitted to the Cross model. Under oscillatory shear, pasted exhibited a solid-like viscoelastic behavior mainly attributed to the volume fraction of swollen granules. Pastes are a mixture of swollen and partially disrupted granules suspended in a macromolecular solution (60 °C) and in a three-dimensional network (25 °C).