Enhancement of the stability of protein-based food foams using trivalent cations

The potential for cations to cross-link protein molecules through electrostatic interaction and thereby enhance foaming properties was investigated using aluminium chloride, β-lactoglobulin and Tween 20 as a model system. The addition of the trivalent cations resulted in a noticable improvement in the foamability and foam stability. Optimal behaviour, specific to the protein and emulsifier concentrations used, was observed at 4–5 μM added aluminium ions. The mode of action of the cations was investigated further using isolated foam lamellae (thin liquid films). The appearance of aggregates in the thin liquid films, non-uniformity of the film, and an increase in the dilational viscosity/elastic modulus of the surface associated with the addition of aluminium cations have contributed to the development of a phenomenological model which explains the observed increase in foam stability