effect of citric acid on pasting properties and swelling power of low and high amylose rice starch

in this study, variations of the pasting properties, swelling power and solubility of two rice starches, low amylose (8.7%) and high amylose (26%) at two citric acid concentrations (0 and 0.01 m) was investigated. the results showed that the peak viscosity and breakdown viscosity of rice starch decreased significantly (p 0.05).the swelling power and solubility of both starch pastes with and without citric acid increased with the increase of the temperature. as the concentration of citric acid increased, swelling power of low and high amylose starch decreased and this event was clearer in low amylose samples. on the other hand, citric acid induced solubility of samples particularly in high amylose rice starches. furthermore, the swelling power and solubility of treatments decreased and increased with increasing amylose content of rice starch, respectively.