Investigation of hydration and glass transition of food protein by inelastic neutron scattering

Nakagawa, Hiroshi   ; Kataoka, Mikio

Low water activity and glass state in dried food restrict the growth of microorganisms and increase the food stability. Vitrification of food is related with the texture. Thus, hydration and vitrification is an essential factor determining the physical property and quality of food. Inelastic neutron scattering (INS) is a promising experimental method for analysis of water mobility and glass transition of food materials. Neutron can give information about vibrational density of states, relaxation and diffusion processes, and mean-square displacements. Molecular Dynamics (MD) simulation gives the information on the molecular structure and dynamics with atomic scale, which is complementary to INS. It was found that the hydration level dependence of the onset of protein glass transition is correlated with the percolation transition of hydration water. The percolation of hydration water induces the protein glass transition.