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INFLUENCE OF THERMAL TREATMENT AND IONIC FORCE ON THE PROPERTIES OF FOAMS CONTAINING SERUM PROTEINS


I. NICORESCU1 *, C. LOISEL 1, C. VIAL 2, A. RIAUBLANC 3, G. DJELVEH 2, G. CUVELIER 4, J. LEGRAND 5
(1) GEPEA-ENITIAA , RUE DE LA GÉRAUDIèRE, 44322, NANTES, FRANCE; (2) LGCB, 24 AVENUE DES LANDAIS, 63174, AUBIèRE, FRANCE; (3) INRA-BIA , RUE DE LA GÉRAUDIèRE, 44316 NANTES, FRANCE; (4) UMR SCALE, AGROPARISTECH ; 1 AVENUE DES OLYMPIADES,

Issue:

SCSCC6, Volume IX, No. 3

Section:

Volume IX, No. 3 (2008)

Abstract:

The aim of our study was to investigate the effect of dynamic thermal treatment on the denaturation and foaming properties of whey proteins, such as overrun, foam stability and texture. Three WPI solutions at 2% w/v (without or with addition of 50 mM and 100 mM NaCl) were heat-treated using a tubular heat-exchanger Actijoule at 100 °C. The native and denatured WPI samples were characterized by chromatography (SEC), dynamic light scattering (DLS) combined with microscopy (FPIA-3000) and micro-differential scanning calorimeter (-DSC). Then, these protein solutions were whipped to produce foams using a Kitchen Aid mixer and foam stability, viscoelastic properties and bubble sizes were measured. Experimental results demonstrated that heat treatment with or without the presence of salt do not lead at an improved overrun. On the other hand, presence of NaCl and heat treatment strongly enhanced firmness and improved foam stability (except for the foam produced from a solution at 50 mM salt). Experimental data have also shown that increasing the proportion of soluble aggregates from 8% (case of the heat treatment without salt) to 70% (case of the heat treatment in presence of 50 mM NaCl) led to a strong improvement in the firmness but also to a more rapid destabilization of foams. It can be asserted that the stability against drainage depends for a great part on controlling the optimal amount of dynamically heat-induced aggregates. A compromise for a better firmness and stability of aggregate-stabilized foams was found for an amount of 17% aggregates in the soluble fraction.

Keywords:

whey proteins isolate, thermal treatment, aggregates, protein foam, stability, microstructure.

Code [ID]:

CSCC6200809V03S01A0010 [0002408]

Full paper:

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