effect of heat treatment and acid hydrolysis on microstructure of corn starch at below gelatinization temperature

Starch in its natural form was not suitable for using in some applications due to its insolubility in water and low stability and needs to be modified# in present study, the heat treatment and acid hydrolysis of corn starch was performed at 60, 65 and 70 °c with the ph of 2, 3 and 4 for 30 and 45 min# the decreasing of ph to 2 and increasing the heating duration time to 45 min had significant effect on increasing the amylose and reducing sugar concentrations# however, the temperature showed no significant effect in range of 60 to 70 °c on the starch hydrolysis# therefore, maximum increasing in amylose (0#13 g/g starch) and reducing sugar (0#15 mg/g starch) concentrations were obtained at 70 °c with the ph of 2 for 45 min#