Factors Determining Yield Stress and Overrun of Whey Protein Foams

Foams were formed by whipping whey protein solutions (15% w/v protein) containing NaCl, CaCl 2 , lactose, or glycine. Foam overrun and yield stress were determined. Foams made from whey protein ingredients have greater overrun and yield stress if the concentration of β‐lactoglobulin is high relative to a‐lactalbumin. The presence of 0.4 M CaCl 2 in the foaming solution increases overrun and yield stress for β‐lactoglobulin and a‐lactalbumin. The high yield stress of β‐lactoglobulin and a‐lactalbumin foams made from solutions containing CaCl 2 suggests that CaCl 2 is altering rheological properties of the interfacial protein film and/or contributing to protein aggregation or network formation in the lamellae.