Chitosan-protein systems: complexes, colloidal gels and interfaces

甲壳素及其主要的工业衍生物壳聚糖构成了当今可用的海洋原料的主要生物聚合物，然而，它们在增值产品方面的潜力尚未得到充分开发。最近的一份报告宣布，到2018年，世界甲壳素和壳聚糖市场预计将超过118 000公吨，而要实现这一增长，需要渗透到新的领域。然而，壳聚糖是一种非常复杂的分子，对科学界和工业界仍然具有挑战性。克服这些限制的一种方法是进一步了解壳聚糖在各种物理状态和其他组分存在下的理化性质。例如，由蛋白质和多糖形成的复合物在应用中发现多种用途，如微量营养素的包封、乳液的稳定、药物等。关于壳聚糖/蛋白质复合物凝聚体的报告在过去很少，然而，近年来考虑到壳聚糖独特的内在性质如生物活性、生物相容性、生物降解性和低毒性，人们重新产生了兴趣。 该项目的长期目标是开发新的壳聚糖-蛋白质复合物为基础的系统，无论是在体相和界面，沿着基本的理解和流变学的方法为基础。本研究将有助于阐明在蛋白质和盐的存在下，壳聚糖在溶液和凝胶状态下的行为的相互作用，沿着的复凝聚，胶体凝胶化和界面粘弹性成膜机制。此外，本提案旨在配制基于脱乙酰壳多糖的高附加值产品，其最终用途证明成本较高是合理的。这项工作的结果将大大提高这种长期以来被渔业视为废物的海洋大分子的价值。预计将给加拿大带来重大的科学和社会经济效益。高素质人员（HQP）的培训将提供一个熟练的劳动力，将在与天然聚合物相关的各种生物基高技术部门就业。

Chitin and its main industrial derivative, chitosan, constitute the principal biopolymers from marine feedstock available today and yet, their potential in terms of value-added products has not been exploited to fullness. A recent report has announced that the world chitin and chitosan market is projected to exceed 118 000 metric tons by 2018, and that penetration into new fields will be required to realize this growth. Chitosan is however a very complex molecule and remains challenging to the scientific community and the industry. One way to overcome these limitations is to develop further knowledge of chitosan physicochemical properties in various physical states and in the presence of other components. For example, complexes formed by proteins and polysaccharides find multiple uses in applications such as encapsulation of micronutrients, stabilization of emulsions, pharmaceuticals, etc. Reports on chitosan/protein complex coacervates have been scarce in the past, however there is a regained interest in recent years considering chitosan unique intrinsic properties such as biological activity, biocompatibility, biodegradability and low toxicity. The long-term objective of this project is to develop novel chitosan-protein complex-based systems, both in the bulk phase and at interfaces, along with fundamental understanding and based on rheological approaches. This research will help to elucidate the interactions that govern the behavior of chitosan in the solution and gel states in the presence of proteins and salts, along with the complex coacervation, colloidal gelation and interfacial viscoelastic film-forming mechanisms. Furthermore, the present proposal aims at formulating chitosan-based high value-added products with end uses that justify a higher cost. Results from this work will greatly valorize this marine macromolecule which has been considered as a waste by the fishing industry for a long time. A significant scientific and socio-economic potential benefit to Canada is expected. Training of highly qualified personnel (HQP) will provide a skilled work force that will be employable in various bio-based high technology sectors related to natural polymers.