Adsorption kinetics and dilatational rheology of plant protein concentrates at the air- and oil-water interfaces.

Adsorption kinetics and dilatational rheology of plant protein concentrates at the air-and oil-water interfaces were investigated at pH 7.0 in 100 mM NaCl. Three interfaces (air-water, triglyceride-water and terpene-water) and four protein concentrates (soy, pea, mung bean and rice) were examined. The dynamic interfacial properties were monitored by axisymmetric drop shape analysis. Kinetic modelling of the early and advanced stages of protein adsorption was carried out using the Ward-Tordai and Graham-Philips thermodynamic approaches. Construction of surface pressure master curves revealed a pseudo equilibrium plateau for legume proteins of ~20, 12, and 22 mN/m at the air, triglyceride and terpene interfaces, respectively. In contrast, rice proteins have a lower capacity to increase the surface pressure at the oil interfaces (<15 mN/m). Data modelling revealed that diffusion is mostly independent of the protein composition, but protein rearrangement at the interfaces was faster at the oil than at the air interfaces. Dilatational rheological...