• foams;
  • yield stress;
  • vane method


The yield stresses of protein foams made from varying protein types (spray dried egg white and whey protein isolate), protein concentrations, whip times, and mixer models were evaluated using vane rheometry. Two methods of analysis (point and slope methods) were investigated. Yield stress values determined by slope and point methods were similar for egg white protein foams but did not agree in the analysis of whey protein foams. Point method values were very reproducible in all foams tested. Egg white protein solutions formed stiffer foams more rapidly and at lower protein concentrations than foams made from whey protein isolate. Vane rheometry was shown to be a reliable method of determining yield stress in protein foams.