Interfacial and foaming interactions between casein glycomacropeptide (CMP) and propylene glycol alginate

Proteins and polysaccharides are widely used in food formulation. While most of the proteins are surface active, only few polysaccharides can adsorb at the air–water interface; this is the case of propyleneglycol alginates (PGA). It is known that caseinglycomacropeptide (CMP), a bioactive polypeptide derived from ?-casein by the action of chymosin, presents a great foaming capacity but provides unstable foams. So, the objective of this work was to analyze the impact of mixing CMP and a commercial variety of PGA, Kelcoloid O (KO), on the interfacial and foaming properties at pH 7.0. It was determined the surface pressure isotherm, the dynamics of adsorption and the foaming properties for CMP, KO and the mixed system CMP–KO.CMP dominated the surface pressure of CMP–KO mixed system. The presence of KO synergistically improved the viscoelastic properties of surface film. The foaming capacity of CMP was altered by KO. KO foam presented a higher stability than CMP foam and it controlled the stability against drainage and the initial collapse in the mixed foam.