Pulse NMR study of glass transition in maltodextrin

A pulse nuclear magnetic resonance (NMR) technique was used to study the gl ass transition in maltodextrins. The spin-lattice relaxation time (T-1) and spin-spin relaxation time (T-2) of different molecular weight maltodextrin s at different moisture contents and temperatures were measured using the p ulse NMR technique. T-1 and T-2 were plotted against temperatures. From the resultant curves, the state transitions were observed and the correspondin g state transition temperatures were determined. The state transition tempe ratures were very close to the glass transition temperatures (T(g)s) determ ined with differential scanning calorimetry, suggesting a strong relationsh ip between glass transition and proton relaxation behavior. Results indicat e pulse NMR-based instrumentation could be very effective for the study of glass transition in food polymers.