Investigation of interactions between two different polysaccharides with sodium caseinate-stabilized emulsions using complementary spectroscopic techniques: Diffusing wave and ultrasonic spectroscopy

Interparticle interactions occurring in sodium casei nate- stabilized emulsions during acidification were investigated with two noninvasive spectroscopy techniques, diffusing wave spectroscopy (DWS) and ultrasonic spectroscopy (US). Two polysaccharides, high methoxyl pectin (HMP) and soy soluble polysaccharide (SSPS), both negatively charged at neutral pH, were used to modulate the behavior of the oil droplets during acidification. Both SSPS and HMP, if added in sufficient amount to the emulsion, prevent aggregation of the emulsion droplets during acidification. However, their interaction behavior is different, and this caused different interparticle interactions. The parameters measured with DWS and US were related to the changes occurring in the oil droplets. Although measuring different dynamics of interactions, our results indicated that the 1/1* parameter measured by DWS and the attenuation of sound measured by US were in good agreement, and both identified well the structural changes occurring in the emulsions during acidification. (C) 2007 Elsevier Ltd. All rights reserved.