Foaming Properties of Proteins as Affected by Concentration

Commercial sodium caseinate and whey protein isolate were evaluated at protein concentrations 0.25 to 16% with ovalbumin solutions as reference. Logarithmic models were developed to express the effect of protein concentration on foam expansion and serum drainage. The kinetics of gas release from milk protein‐stabilized foams followed a three‐phase pattern. Low foam collapse rates were observed in initial and final phases while rapid collapse occurred during the transition phase. No transition was observed for ovalbumin‐stabilized foams. Globally, foam collapse rate increased with increasing protein concentration. Apparent viscosity of protein‐stabilized foams increased with concentration to a maximum; beyond which, a reverse trend was observed. Maximum viscosities of milk protein foams were at concentrations & lt;0.5%, while ovalbumin foams showed maximum viscosity around 2% protein.