ABSTRACT
Biological tissues of either animal or vegetable origin and especially the foods derived from them are heterogeneous amorphous solids; these characteristics complicate any detailed description of their molecular structure and dynamics. Amorphous solids exhibit many of the usual physical characteristics of more easily studied crystalline solids. Amorphous solids undergo transitions that reflect thermally activated, cooperative changes in the dynamics of the molecules. The most familiar and best-studied transition involves the change from a rigid, brittle, glassy state to a soft, flexible, rubbery state. The complexity presents great difficulties to food chemists and engineers for the characterization of foods on the molecular level. Phosphorescence imaging has great potential for monitoring molecular mobility and dynamical transitions within the heterogeneous matrix of foods. As this review has illustrated, triplet-state probes have the potential to monitor the physical state and changes in the state of specific components in foods.
