Mixed soy globulins and β-lactoglobulin systems behaviour in aqueous solutions and at the air–water interface

Abstract

It has been studied in this work the effect of mixing soy globulins (b-conglycinin and glycinin) with blactoglobulin (blg) both in the bulk phase and also in their interfacial (airewater interface) and foaming properties, at pH 3.0 and 7.0 and 20 C. The analyzed properties of these systems were: particle size distribution (by dynamic light scattering (DLS)); dynamics of adsorption and surface dilatational modulus (by tensiometry); foam formation and stability (by conductimetric and optical measurements). Results revealed that mixture of 7S soy globulin and blg at pH 7.0 presented a synergistic effect that is reflected in the formation of interfacial films of enhanced elasticity. The foaming properties were also improved (better foam capacity with foams made up by smaller air bubbles). There exists a close relation between these results and that obtained by DLS (existence of a complexation between b-conglycinin and blg).