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

The rheological behavior at 25 and 60 degreesC 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 degreesC 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 mum, while that of cooked starch ranged from 59 to 66 mum 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 degreesC) and in a three-dimensional network (25 degreesC) (C) 2004 Elsevier Ltd. All rights reserved.