Preparation of cold water-soluble potato starch and its characterization

Alcoholic-alkaline treatment of starch results in granular cold water-soluble starch. The nature of structural alterations occurred in starch due to the treatment is however relatively vague. Potato starch was treated at various alcoholic-alkali conditions and subjected to light microscopy, Fourier transform infrared (FTIR) spectroscopy and X-ray diffractometry. Alcoholic-alkaline treatment increased the solubility of starch in a temperature-dependant manner. The treated starch suspension was also more turbid than that of native counterpart at all concentrations, due probably to either the presence of higher number of water-soluble granules or leaching of amylose during alkalization. Alcoholic-alkali treating of starch did not disintegrate the granular assembly; albeit, decreased the crystalinity. Both native and treated starches showed the B-type pattern in X-ray diffractometry. FTIR spectroscopy revealed that characteristic peaks of hydroxyl groups were of low transmittance in spectrum of treated starch compared with that of native counterpart implying in participation of hydroxyl groups in interactions with modifying agents.