Abstract

Heat moisture treatment is the physical method of modification to give sweet potato flour desired physical properties for application in the manufacture of flour based products. Two varieties of sweet potato flour were characterized to understand the changes of physicochemical properties and micro-structural profile upon heat moisture treatment. Sweet potato flours were analyzed its pasting properties, crystallinity characteristics and starch granule structure by using Rapid Visco Analyzer, X-ray Diffraction and Scanning Electron Microscopy, respectively. The results indicated that the heat moisture treatment affected characteristics of all sweet potato flour were treated at, moderate and high temperature. There were a decreasing in peak viscosity and an increase in cold paste viscosity following heat-moisture treatment compare to native sweet potato. The changes differ between yellow sweet potato and purple sweet potato. This indicates that different starches may respond differently to physical modification. The diffractograph of flour samples showed the main peak mainly in 15°, 16°, 17°, 22° and 23°, that correspond to the spacing-d in 5, 8, 5, 3, 4, 9 and 3, 8 Å, respectively. This reflection indicates the presence of a A-type crystalline.

Keywords:

Heat moisture treatment, modified sweet potato flour, starch granule structure, thermal property,

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The authors have no competing interests.

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