Influence of physical state and molecular mobility of freeze-dried maltodextrin matrices on the oxidation rate of encapsulated lipids

A glassy model of freeze-dried maltodextrin was developed for the encapsulation of flaxseed oil. Kinetics of lipid oxidation have shown that the matrices efficiently protected lipids from oxidation for a moisture content corresponding to the monolayer value. An NMR method based on the 2nd moment, M(2) was used to study the molecular mobility and physical state of the freeze-dried maltodextrin and water mixtures. Physical state transitions were observed at temperatures very close to the glass transition temperature (Tg) determined from the equation of Vuataz (1999), suggesting a relationship between glass transition and proton relaxation behavior. No apparent relation between molecular mobility and oxidation rate were observed whatever the DE of maltodextrins.