Effect of acid-alcohol treatment on the molecular structure and physicochemical properties of maize and potato starches

The molecular structure and physicochemical properties of acid-alcohol treated maize, and potato starches (0.36% HCl in methanol at 25 degreesC for 1-15 days) were investigated. The yields-of the modified starches were ranging from 91 to 100%. The average granule size of modified starches decreased slightly. The solubility of starches increased with the increase of treatment time, and the pasting properties confirmed the high solubility of modified-starches. The gelatinization temperatures and range of gelatinization increased with the increase of treatment time except T-o (onset temperature) of maize starch. Molecular structures of modified starches suggested the degradation of starches occurred mostly within the first 5 days of treatment, and degradation rate of potato starch was higher than maize starch both in amylopectin and in amylose. Maize starch was found less,susceptible to acid-alcohol degradation than potato starch. (C) 2003 Elsevier Ltd. All rights reserved.