Physicochemical properties of pronase‐treated rice glutelin

Abstract

Rice glutelin protein was extracted from defatted medium-grain rice by alkali extraction followed by acid precipitation. Extracted glutelin was hydrolyzed with Pronase E, a bacterial protease, and the functional properties of hydrolysates were evaluated. Nitrogen solubility of pronase-treated glutelin protein increased from pH 2 to pH 12. Similarly, foaming and emulsion properties of hydrolyzed protein also showed improved characteristics. The emulsion activity, expressed as the turbidity of diluted emulsions, was significantly greater (P ≤ 0.05) for hydrolyzed samples. However, turbidity for all samples decreased with increased homogenization time, indicating a decrease in the volume of dispersed oil. There were significant changes in apparent viscosity as a function of shear rate, with viscosity decreasing with increasing shear rate. The viscosity of dispersions of all hydrolyzed samples was significantly lower than that of the native sample at all shear rates tested. Enzymatic hydrolysis of rice endosperm storage glutelin proteins appeared to improve the functional characteristics of the hydrolyzed proteins.

Characterization and In Vitro digestibility of rice protein prepared by enzyme-assisted microfluidization: Comparison to alkaline extraction

“…Protease treatment has been widely applied to extract rice protein by improving the solubility of protein hydrolysates and to modify its physicochemical and functional properties (Anderson et al, 2001;Paraman et al, 2007). This method could cause the generation of bitter hydrolysates.…”

Comparison between protein functional properties of two rice cultivars

“…There is also some information about functional properties of the endosperm-protein fractions and of glutelins (Agboola, Ng, & Mills, 2005;Anderson, Hettiarachchy, & Ju, 2001;Tang, Hettiarachchy, Ju, & Cnossen, 2002). Moreover, Chandi and Sogi (2007) have compared the functional properties of proteins from different rice cultivars.…”

Preparation of Rice Endosperm Protein Isolate by Alkali Extraction

“…A number of methods have been reported for preparing rice protein isolates (Morita and Kiriyama 1993;Shih and Daigle 1997;Shih et al 1999;Anderson et al 2000;Paraman et al 2006). The most common method of extracting rice endosperm protein is alkali extraction followed by isoelectric precipitation (Shih et al 1999;Anderson et al 2000;Paraman et al 2006). In the alkali extraction method, the protein could be extracted with either disulfide reducing agents such as DTT, mercaptoethanol, or denaturing agents such as urea or SDS (Tecson et al 1971;Padhye and Salunkhe 1979).…”