Investigating surface properties of a blend of phycocyanin and chia mucilage for its possible applications in dispersed systems

The study of the effect of protein-polysaccharide interactions on the properties of air-water and oil-water interfaces has special relevance in the development of processed dispersions, such as foams or emulsions. Specifically, the analysis of the interfacial behaviour of mixtures that exhibit associative interactions. A surface characterization of a system consisted of a 1:1 mixture of phycocyanin and chia mucilage was studied by comparison with both unitary aqueous systems. Surface activity was assessed through surface tension measurements, revealing that the mixture achieved a surface tension of approximately 52 mN/m at 0.1 wt%, like pure phycocyanin, despite its lower protein content. Interfacial rheology showed a significant enhancement in viscoelastic properties for the mixture, with elastic and viscous moduli (G′ and G″) approximately two orders of magnitude higher than those of phycocyanin alone, indicating a reinforced gel-like behaviour. In contrast, chia mucilage alone formed a fluid-like film with G″ > G′. Zeta potential measurements confirmed that the mixture retained a high negative surface charge (like phycocyanin), ensuring colloidal stability. The foaming capacity increased with concentration for phycocyanin, which produced the greatest volume expansion. In the 1:1 phycocyanin–chia mucilage blend, overrun was intermediate but protein-efficient up to a concentration of 0.25 wt%, beyond which the increasing bulk viscosity curtailed further aeration. Chia mucilage alone consistently displayed the lowest foaming capacity. These findings demonstrate a cooperative interaction between phycocyanin and chia mucilage, resulting in improved surface structuring and mechanical strength, making the blend a promising candidate for sustainable, bio-based stabilizers in dispersed systems. • Phycocyanin and chia mucilage create bioactive surfaces with unique properties. • Phycocyanin forms a resilient, gel-like surface with strong molecular interactions. • Chia mucilage builds a fluid-like film, limiting intermolecular bonding. • Their combination boosts surface elasticity, reinforcing structural integrity. • Cooperative effects offer great potential to enhance the stabilization of dispersions.