Moisture diffusivity in food materials

► Self diffusivity of water in biopolymer matrices can be predicted using free volume theory. ► Self diffusivity of biopolymers in solution is predicted using generalised Stokes-Einstein relation. ► The Fickian mutual diffusivity can be linked to the self diffusivities via the Darken relation. ► Moisture diffusion in dense biopolymer and sugar matrices is showing universal behaviour.