CHITOSAN BEHAVIORS IN A DISPERSION OF UNDECYLENIC ACID

Chitosan is able to flocculate or stabilize aqueous dispersed media containing undecylenic acid. These flocculation/dispersion phenomena were studied by potentiometric, UV spectrometric and quasi-elastic light scattering techniques. Parameters such as pH, ionic strength of the media and total lipid concentration have a great influence on the interactions occurring between chitosan and the lipid particles. Adequate pHs, ionic strengths and a lipid concentration above a certain limit are required to obtain flocculated or dispersed systems. High ionic strengths, as well as dilution, tend to increase the particle sizes and destabilize the dispersions. On the other hand, high lipid concentrations yield smaller chitosan coated particles. A mechanism of adsorption of chitosan chains onto lipid particles is proposed, which explains the influence of the various parameters.