Behavior of foods studied by thermal analysis - Introduction

In the investigation of foods by thermal analysis and calorimetric techniques, many physicochemical effects can be observed in the temperature range between -50 and 300degreesC. These thermal phenomena may be either endothermic, such as melting, gelatinization, denaturation, evaporation or exothermic, such as crystallization, oxydation, fermentation. Glass transitions are observed as a shift in the base line; this information, associated with water content and water activity determinations, is of particular interest in relation to storage of food powders but also for gas retention in powders foreseen to foam when dissolved. The thermal behavior of foods strongly depends on their composition; we therefore present first the thermal characteristics of the major food constituents: carbohydrates, lipids, proteins, water and then of raw and reconstituted food.