Predicting the quality of dehydrated foods and biopolymers - Research needs and opportunities

Drying processes affect the quality of the final food biopolymer product. The texture, density, wetability, caking, rehydration capacity and mechanical properties of the dried food biopolymer depend on: the product properties, the drying process conditions and the product residence time distribution in the dryer. The interrelationship between dried product quality and drying process conditions is not sufficiently explored in literature because of limited understanding of the physico-chemical mechanisms affecting product quality, and of the effect of these mechanisms on transport properties. Recent advances in material and polymer science research, however, provide the tools and methodologies needed to understand in depth the quality changes during drying. The current work reviews the approaches of conventional drying theories and presents recent advances in polymer science on modelling solvent absorption by glassy polymers based on the glass-transition theory. Opportunities presented by the glass transition theory towards explaining quality changes during drying are identified and the framework of a recent mathematical model that can be used to integrate the drying and polymer-science approaches is then presented.