INVESTIGADORES
MAMMARELLA Enrique Jose
congresos y reuniones científicas
Título:
Effect of limited enzymatic hydrolysis on adsorption and foaming behaviour of milk whey protein
Autor/es:
PÉREZ, ADRIÁN; CARRARA, CARLOS; CARRERA-SÁNCHEZ, CECILIO; MAMMARELLA, ENRIQUE; RUBIOLO, AMELIA; SANTIAGO, LILIANA; RODRÍGUEZ-PATINO, JUAN
Lugar:
Porto, Portugal
Reunión:
Conferencia; Internacional Functional Foods Conference; 2008
Institución organizadora:
Universidad Católica Portuguesa de Porto - CyTED
Resumen:
One of the processing treatments of proteins to improve its use as a functional ingredient in food systems is enzymatic hydrolysis. This may improve the solubility, emulsifying and foaming properties of protein preparations. The present study was initiated with the aim to understand how limited hydrolysis can improve the functionality of milk whey proteins. More particular, it is focused on the contribution of the interactions between milk whey protein and polysaccharides in solution and at the air-water interface on foaming properties (foam formation and its stability). In this contribution we have studied the extent to which the functional properties (kinetics of adsorption, surface dilatational properties, foam capacity and foam stability) of a milk whey protein isolate (WPI) can be altered by limited enzymatic hydrolysis (degree of hydrolysis, DH, 0, 1, 3 and 5%). The functional properties of aqueous solutions of hydrolysates were determined at pH 7, ionic strength 0.05 and at 20 °C. Hydrolysates were prepared by a batch process from WPI solution at 4.0% wt at pH 8 and 50 °C, using alpha-chymotrypsin (EC 3.4.21.1) type II immobilized on agarose microparticulate. The pH and DH were controlled using the pH-stat method. We have observed that the degree of hydrolysis (DH) improves the surface activity, the rates of diffusion, penetration/adsorption/unfolding and rearrangement of the protein at the air-water interface. The surface dilatational modulus of adsorbed films also increases with DH. However, the viscoelasticity of the adsorbed film decreases with the hydrolysis. The hydrolysis also improves the foam capacity, the gas and liquid retention in the foam and produces smaller bubbles. The optimum foam stability was observed at DH = 3%. Finally, the foam capacity can be explained by the rate of diffusion of the protein and its capacity to form elastic adsorbed films the air-water interface, whereas the foam stability correlates well with the surface activity and the surface dilatational modulus at long term adsorption.