Thongngam Masubon, McClements D Julian
Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, USA.
J Agric Food Chem. 2004 Feb 25;52(4):987-91. doi: 10.1021/jf034429w.
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.
壳聚糖是一种阳离子生物聚合物，因其独特的营养和物理化学性质而在食品工业中有许多潜在应用。其中许多性质取决于其与阴离子表面活性分子相互作用的能力，如磷脂、表面活性剂和胆汁酸。本研究的目的是使用等温滴定量热法（ITC）、表面活性剂选择性电极（SSE）和浊度测量来表征壳聚糖与模型阴离子表面活性剂（十二烷基硫酸钠，SDS）之间的相互作用。ITC和SSE表明，SDS通过高度放热的相互作用与壳聚糖强烈结合。浊度测量表明，壳聚糖与SDS形成了强烈散射光的不溶性复合物。在被表面活性剂饱和之前，每0.1 wt%壳聚糖结合约4 mM的SDS。100 mM NaCl的存在使SDS-壳聚糖相互作用明显减弱，这表明其起源是静电作用。本研究提供了有关壳聚糖与阴离子表面活性脂质之间分子相互作用的起源和特征的信息，这可能有助于合理设计具有特定营养和功能特性（如降低胆固醇或脂肪替代）的基于壳聚糖的食品成分。
