PREDICTING THE QUALITY OF DEHYDRATED FOODS AND BIOPOLYMERS - RESEARCHNEEDS AND OPPORTUNITIES

Drying processes affect the quality of the final food biopolymer produ ct. The texture, density, wetability, caking, rehydration capacity and mechanical properties of the dried food biopolymer depend on: the pro duct properties, the drying process conditions and the product residen ce time distribution in the dryer. The interrelationship between dried product quality and drying process conditions is not sufficiently exp lored in literature because of limited understanding of the physico-ch emical mechanisms affecting product quality, and of the effect of thes e 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 an d presents recent advances in polymer science on modelling solvent abs orption by glassy polymers based on the glass-transition theory. Oppor tunities presented by the glass transition theory towards explaining q uality changes during drying are identified and the framework of a rec ent mathematical model that can be used to integrate the drying and po lymer-science approaches is then presented.