Structural and Functional Properties of Caseinate and Whey Protein Isolate as Affected by Temperature and pH

Abstract

ABSTRACT The structural properties, i.e., active sulfhydryl (SH), flexibility and hydrophobicity, and functional properties, i.e., solubility, emulsion activity (EA), emulsion stability (ES), foam overrun (FO) and foam stability (FS), of commercial sodium caseinate (SC) and whey protein isolate (WPI) solutions were investigated at pH 6, 7 and 8 and at 25, 55 and 65°C. WPI contained a higher concentration of active SH and was more hydrophobic than SC. WPI provided comparable solubility and EA, lower FO, but higher FS than SC. Temperature and pH effects on the two proteins were somewhat inconsistent.