The objective of this work was to determine the effects of high intensity ultrasound application on the foaming properties of soy protein-polysaccharides mixed solutions. To this end, foaming parameters during foam formation were analyzed. The samples were sonicated for 20？min using ultrasonic processor Vibra Cell Sonics, and model VCX 750 at a frequency of 20？kHz and an amplitude of 20%. The foams were produced by a Foamscan instrument. The evolution of the bubble size change in the foam was also determined by a second CCD camera. For all foamed systems, at two pHs 3 and 7, Foam expansion and Relative Foam Conductivity showed a great increase after ultrasonic treatment. Other parameters studied did not show difference. On the other hand, Final Time of Foaming and the Total Gas Volume incorporation for foams formation were correlated with the Relative Foam Conductivity decrease and the Foam Expansion increase when HIUS were applied in every system. Comparative bubble size and shape during the foam formation according to the treatments and pH used confirmed the parameters results. 1. Introduction Proteins are a particular class of biopolymers with tension-activity character; as a result, they are fundamental in dispersed systems formations such as foams and emulsions. The use of soy proteins as functional ingredients in food manufacturing is increasing because of their role in human nutrition and health. Native soy protein, because of its quaternary and compact tertiary structure, has limited foaming [1–3] and emulsifying [4] properties. However, structural modifications by chemical methods such as deamidation, succinylation, reductioning, or denaturation allow greater conformational flexibility of this protein, improving its surface behavior and functionality [5–8]. One way to increase soy proteins functionality would be the high intensity ultrasound (HIUS) application. The effect of ultrasound is related to cavitation, heating, dynamic agitation, shear stresses, and turbulence [9]. It may cause physical changes producing protein aggregates through covalent and noncovalent bonds. Polysaccharides are used in admixture to proteins mainly to enhance stability of dispersed systems. They can strongly enhance the stability of protein foams by acting as thickening or gelling agents [10]. In addition, the surface-activity difference along the structure of polysaccharides influences the foam formation parameters of proteins as well as the protein state and concentration. In the present work, various polysaccharides solutions were added to soluble soy protein
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