title: Surface functional properties of native, acid-treated, and reduced soy glycinin. 2. Emulsifying properties.
abstract: Emulsifying properties of native and chemically modified soy glycinins were studied. The influence of ionic strength, protein sample composition and concentration, and assay conditions on the flocculation-creaming process and coalescence resistance was analyzed. Differences in these emulsifying properties were exhibited by native glycinins, which have a variable content of 4S, 11S, and 15S forms. Structure and functionality of native glycinin were modified by means of combined treatments: mild acidic treatments without heating or with heating at variable time and with or without disulfide bonds reduction. Modified glycinins presented different degrees of deamidation, surface hydrophobicity, and molecular mass. A slight enhancement of emulsifying stability at moderated deamidation degrees was observed. In different protein samples, a positive relationship between the flocculation-creaming rate constant and equilibrium oil volume fraction of emulsions with surface hydrophobicity was detected. A remarkable difference was observed between reduced and nonreduced samples, mainly with respect to behavior at low or high ionic strength.
authors.affiliation: Centro de Investigación y Desarrollo en Criotecnología de Alimentos (CIDCA), Universidad Nacional de La Plata, Argentina. jrwagner@nahuel.biol.unlp.edu.ar
authors.forename: J R
authors.initials: JR
authors.lastname: Wagner
authors.forename: J
authors.initials: J
authors.lastname: Guéguen
mesh_terms: D005079:Excipients / Q000737:chemistry*; D005916:Globulins / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D030262:Soybean Proteins; D013025:Glycine max; D013499:Surface Properties
chemical_list: D005079:Excipients; D005916:Globulins; D030262:Soybean Proteins; C011474:glycinin