EFFECTS OF HIGH ULTRASOUND INTENSITY ON FOAM STABILITY AND INTERFACIAL RELATIONSHIP OF SOLUBLE SOY PROTEIN ISOLATE

MARTÍNEZ, KARINA DAFNE; CARRERA SANCHEZ, CECILIO

Biointerface Research in Applied Chemistry

Biointerface Research in Applied Chemistry

Año: 2016

2069-5837

The objective was to determine the effectof ultrasound (HIUS) on the stability of foams and interfacial properties atequilibrium conditions at pH 7 and 3 of soluble fraction of soy protein isolate(SSPI). The samples were sonicated for 20 min using an ultrasonicprocessorVibra Cell Sonics.The foams were produced using a foaming commercial instrumentFoamScan. Foam formation and stability were measured by conductimetric andoptical methods. Moreover, the evolution of the bubble size change in the foamwas determined by a second CCD camera. Measurements of the variations ofsurface pressure (π) with the molecular area (A) of films were analyzed at theair-water interface with an automated KSV Langmuir mini-trough.In spite of thebetter foam obtained after HIUS, trough the relative foam conductanceCf%, thestabilizing parameters in the foam: half-life time t½, relaxation timescorresponding to the kinetics of liquid: td and tdc depended of pH studiedwhich would be relating with the protein state and quantity of SSPI in eachcase.There are exist a shift of the p-A isotherm to higher values of area whenultrasound were applied at pH 7, which could be related to solubilization ofmicroaggregates in the sonication process. However, when HIUS was applied atsolution at pH 3 the resulting isotherm presented a similar behavior than theobtained from the untreated one. This, can be explain by the denaturing effectproduced by the acidic solution.