Relationship between interfacial and foaming properties of a Porphyra dioica seaweed protein concentrate

Abstract

Porphyra dioica macroalgae can be regarded as a food-grade protein source that can be used for the stability of dispersed food systems. This work is focused on the foaming properties of a seaweed protein concentrate (SWE) from Porphyra dioica . The characterisation of air-water (A/W) interfacial layers formed after the SWE adsorption was carried out by means of interfacial tension, interfacial viscoelastic measurements and step deformation tests. These results were related to those obtained for SWE stabilized foams. Interfacial shear measurements indicate that not extensive protein-protein interactions at the A/W interface were developed (G' s = 1.0 ± 0.1·10 −2 mPa m), whereas the dilatational response (E' s = 23.5 ± 0.5 mN/m) match with the formation of a rigid interface as a result of a densely packed structure. Even if the foaming properties obtained for SWE (overall foam capacity, OFC, = 0.74 ± 0.01 mL/s) are similar to those reported for other commercial protein systems, its lower stability (t 1/2 = 204 ± 4 s) would indicate the need of adding stabilizers for an adequate shelf life of the final food product. The suitability of combining dilatational and interfacial shear rheology to predict the dynamics of dispersed systems was proven to be relevant to acquire insights of complex interfaces. • Porphyra dioica algae could be a food-grade protein source for dispersed systems. • Dilatational response indicated the formation of a rigid interface. • The weak interfacial shear response suggested the formation of a densely packed structure. • Dilatational and interfacial shear rheology was combined to predict the dynamics of foams. • Foaming properties were similar to those reported for commercial protein systems.