The effects of two common organic acids; lactic and acetic acids (150 mg/kg) on physicochemical properties
of native and cross-linked wheat starches were investigated prior and after gelatinization. These
acids caused formation of some cracks and spots on the granules. The intrinsic viscosity of both starches
decreased in the presence of the acids particularly after gelatinization. Water solubility increased while
water absorption reduced after addition of the acids. The acids caused reduction in gelatinization temperature
and enthalpy of gelatinization of both starches. The starch gels became softer, less cohesive, elastic
and gummy when acids were added. These changes may indicate the degradation of the starch molecules
by the acids. Cross-linked wheat starch was more resistant to the acids. However, both starches became
more susceptible to the acids after gelatinization. The effect of lactic acid on physicochemical properties
of both starches before and after gelatinization was greater than acetic acid.