Effects of pH and Gamma Irradiation on the Physicochemical Properties of Corn Starch

Abstract

To develop a production method for modified starches with less pollution, pH adjustment and gamma irradiation were applied to commercial com starch. Blue values were significantly decreased, while alkali number, optical transmittance and solubility markedly increased when gamma irradiation was applied to pH 2 adjusted com starch. Water binding capacity and swelling power at pH 5 were the highest among the samples. Gelatinization viscosity was considerably affected by gamma irradiation and pH of the starch. Gamma irradiation of pH 2 adjusted starch showed the lowest peak viscosity and the best cooling stability among the tested samples. Therefore, the production of modified starch with low viscosity as well as with sufficient viscosity stability seems feasible by controlling the pH of the starch and gamma irradiation.