Controlled Release Systems for Food Application

The controlled active molecule-delivery technology has progressed over the last decades, with the development of sustained release systems for application in food sector. It is useful to control the rate and extent of food digestion in different regions of the gastrointestinal tract (GIT) and release of an active compound with the ultimate goal of controlling bioavailability and satiety of blood levels. The nature, molecular weight and concentration of a carrier material, as well as the lipophilic/hydrophilic character of the loaded active component, its concentration, interfacial properties and the particle size distribution are some of the key factors that determine the delivery performance of these systems. pH variation, temperature change, variation of the redox potential and enzyme activity are stimuli which most often induce the release of an active molecule in a medium. In order to develop food additives with controlled release, their processing in the gastrointestinal tract has to be understood; therefore, a general description of the digestive system is given and associated to the currently used in vitro experimental models. This chapter aims to give a useful overview on the gastrointestinal fate of the most frequently used carrier materials and structures of food-grade delivery systems. At the end, mathematical models most useful in fitting to the experimental data of release profiles and resolving the mechanisms implied in controlled release are summarized.