ABSTRACT
486The phase and state of food materials is of significant importance to food materials properties, performance, and structure, from production steps to processing, packaging, sensory experience, digestion, and nutrient delivery. Phase transitions of pure chemical substances are often well-known material properties, although data on thermodynamic properties of many organic food components have not been reported or may not be available. Common phase and state transitions occur at temperatures that are pressure-dependent and specific to each material. In foods, internal and external pressure and temperature conditions contribute to their physical state during processing, storage, and consumption. Most phase and state transitions in food systems are changes in material properties that occur in their main components: carbohydrates, lipids, proteins, and water. The physical state and engineering properties of most foods are defined by the physical state of their major components, especially that of carbohydrates, lipids, proteins, and water. However, phase and state transitions occur also at submolecular and supramolecular levels in complex food composites, and the importance of such phase and state transitions of food components to food science and engineering is increasingly recognized.
