Characterization of Molecular interactions between Chitosan and Sodium Dodecyl Sulfate ( SDS ) 1 G Geetha

Chitin is the next most abundant natural polysaccharide after cellulose. It can be found in shells of shrimps, crabs and crayfish, which are waste products in food industry. Chitosan is becoming popular in an increasing number of industrial applications due to its availability, low cost and biodegradability. 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), surfactantselective 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. 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