Effect of ethanol concentration on the physicochemical properties of waxy corn starch treated by hydrochloric acid

Waxy corn starch was treated in 50, 70 or 90% of ethanol solutions containing 0.36 or 1.39% HCl at 65 degreesC for 1 h. The recovery yields of treated starch were higher than 96%. The average granule size, maximum wavelength of the spectrum of iodine coloration (lambda(max)), pasting viscosity, gelatinization onset temperature (T-o), average molecular weight and average chain length of starch decreased after treated, while no obvious change on X-ray diffraction pattern and increase in solubility of treated starch was also found. The changes on pasting viscosity, T-o, average molecular weight and solubility of treated starch increased with increasing ethanol and acid concentrations. It was found that the solubility of acid-ethanol treated waxy starch was a function of T/T-o (T was the temperature used for solubility measurement). At T/T-o below 1.2, the solubility of starch linearly correlated with T/T-o value (r(2) = 0.984). (C) 2004 Elsevier Ltd. All rights reserved.