Effects of addition of acetic acid on some physicochemical properties of wheat starch

Acetic acid and starch are two highly consumed components in preparation of foods such as sauces، soups and fermented bread dough. Therefore، determination of the starch functional properties in presence of acetic acid can be useful in determination of the characteristics of such products. In this study، the effects of acetic acid (150 mg/k) on the functional properties of wheat starch were investigated. Scanning electron microscopy images revealed the appearance of some spots on the surface of starch granules. Starch water solubility increased from 4. 70 to 5. 43% but water absorption reduced from 4. 96 to 4. 53 (g/g). Intrinsic viscosity as an indication of molecular size and weight reduced from 174. 08 to 152. 75 (mL/g) that is an indication of starch molecular weight reduction in the presence of acetic acid. Gelatinization temperature decreased from 64. 50 to 64. 41 °C and enthalpy of gelatinization reduced from 9. 17 to 8. 14 (J/g). Using a Rapid Visco Analyser it became clear that the peak and final viscosities and peak time decreased significantly (P<0. 05). Overall، the results showed some partial degradation of starch molecules in the presence of acetic acid resulting in changes in physicochemical properties of wheat starch.