Characterization of Interactions between Chitosan and an Anionic Surfactant

Abstract

Chitosan is a cationic biopolymer that has many potential applications in the food industry because of its unique nutritional and physiochemical properties. Many of these properties depend on its ability to interact with anionic surface-active molecules, such as phospholipids, surfactants, and bile acids. The purpose of this study was to characterize the interaction between chitosan and a model anionic surfactant (sodium dodecyl sulfate, SDS) using isothermal titration calorimetry (ITC), surfactant-selective electrode (SSE), and turbidity measurements. ITC and SSE indicated that SDS bound strongly to chitosan via a highly exothermic interaction. The turbidity measurements indicated that chitosan formed insoluble complexes with SDS that strongly scattered light. The chitosan bound approximately 4 mM of SDS per 0.1 wt % chitosan before becoming saturated with surfactant. The SDS-chitosan interaction was weakened appreciably by the presence of 100 mM NaCl, which suggested that it was electrostatic in origin. This study provides information about the origin and characteristics of molecular interactions between chitosan and anionic surface-active lipids that may be useful for the rational design of chitosan-based food ingredients with specific nutritional and functional characteristics, e.g., cholesterol lowering or fat replacement.

Complexes of oppositely charged polyelectrolytes and surfactants – recent developments in the field of biologically derived polyelectrolytes

“…38,42,[158][159][160][161][162][163][164] It was shown that SDS and chitosan form insoluble complexes well below the cmc of the surfactant and in a high polyelectrolyte excess, indicating a strong cooperative behavior ascribed to the hydrophobic interactions among the bound surfactant molecules. 38,160 In the work done by our group we also found that chitosans with different molecular weights and different degrees of acetylation (DA) (from ca. 2% to 15%) mixed with SDS, sodium dodecyl benzene sulphonate (SDBS) and sodium lauryl ether sulphate with an average of 2 ethylenoxide units per surfactant (SLES) form insoluble complexes over a wide range of mixing ratios and concentrations.…”

Applied Usage of Yeast Spores as Chitosan Beads

“…This possibility was tested using a bile acid, taurocholic acid. Bile acids are cholesterol derivatives; previous reports have shown adsorption by chitosan (32,33). Following incubation of freeze-dried spores with 3 mM taurocholic acid solution, the residual amount of taurocholic acid was measured by HPLC and used to calculate removal by spores.…”

Biopolymer-stabilized emulsions on the basis of interactions between β-lactoglobulin and ι-carrageenan

“…Interfacial engineering could be used to improve the stability of oil-in-water emulsions against environmental stresses or to create emulsions with novel functional properties. Emulsions stabilized by multilayered membranes, such as chitosan, whey proteins, pectin, and carrageenan, were recently studied by McClements et al, and their results indicated improved emulsion stability against pH, ionic strength, thermal processing, and freezing [1,2,[6][7][8][9][10][11][12]. Among them, β-lactoglobulin and ι-carrageenan were found to be an interesting biopolymer pair to prepare stable O/W emulsions [12].…”