Structural Advances in the Understanding of Carbohydrate Glasses

Progress has been made in the understanding of the physical properties of carbohydrate-water systems in terms of their temperature and water-dependent phase transitions. This has resulted in an extensive use of phase and state diagrams to predict both behavior during processing and the storage stability of carbohydrate-based foods and pharmaceutics. The glass transition temperature is of particular importance for the stability of amorphous foods and pharmaceutics as it is strongly depressed by water. This chapter presents an extended framework that facilitates rational use of glassy carbohydrates in food and pharmaceutical applications. A distinction is made between processes that influence the product stability and are dependent on the viscosity of the system and those that are not. It is important to investigate whether the structural variations have an impact on the dynamics of the carbohydrate-water systems. Several techniques, such as NMR and EPR spectroscopy and scattering techniques such as neutron and X-ray scattering can in principle be used to obtain quantitative information on such structure-property relations. The current findings on the structure of carbohydrates in the glassy state and the dependence of the structure on composition may help to define rational strategies to optimize the stability of products in the food and pharmaceutical fields.