Effect of limited enzymatic hydrolysis on structure and emulsifying properties of rice glutelin

Abstract

The influence of the degree of hydrolysis (DH) on the structure, solubility, rheology, and emulsifying properties of rice glutelin was investigated. Structural properties were characterized using analysis of molecular weight distribution, surface hydrophobicity, intrinsic fluorescence, and Circular Dichroism (CD) spectra. Protein hydrolysis changed molecular weight, increased flexibility, altered surface hydrophobicity, and increased solubility. Oil-in-water emulsions were prepared from rice glutelin with different DH (0.5%, 2%, and 6%) and their stability to storage, pH, salt, and thermal processing was assessed. The storage, pH, salt, and temperature stability of the emulsions increased with decreasing hydrolysis. Emulsions prepared with 2% DH rice glutelin were stable over a range of environmental conditions: pH 7–9; NaCl <100 mM (pH 7); temperatures < 90 °C (pH 7, 0 mM NaCl) studied. These results will facilitate the formulation and production of natural emulsion-based products using rice glutelin as an emulsifier.