Physicochemical properties of alkali-treated oat globulin

Abstract

Oat globulin dispersions (10% w/v) were incubated at an initial pH of 9.8 at 25, 37, and 55°C over a period of 96 h. Turbidity increased at 25 and 37°C with the formation of insoluble aggregates and decreased at 55°C with little precipitation. The free SH content decreased progressively with time, while the surface hydrophobicity was increased at 25°C and decreased at 37°C. Differential scanning calorimetry showed progressive increases in denaturation temperature and decreases in width at half-peak height. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis demonstrated formation of soluble aggregates at 55°C and degradation of oat globulin polypeptides at 25 and 37°C, possibly due to proteolysis by protease(s) coextracted with the protein. No significant racemization of amino acids was observed in the alkali-treated protein.