There has been a tremendous increase in the number of food products containing bioactive components with a health promoting or disease preventing effect. Bioactive food components can be divided into bioactive molecules and bioactive living cells (probiotics). Both bioactive molecules and bioactive living cells may benefit from encapsulation since many report low survival of bioactivity due to adverse effects of (i) processing and storage in the products that serve as vehicles and due to (ii) deleterious circumstances during transport through the gastrointestinal tract. For probiotics, it may even be mandatory to apply protection by encapsulation as the survival of probiotics in traditional products such as in dairy foods and powdered formulas is low. Encapsulation promotes not only viability but more importantly also protects the functionality, and may facilitate targeted release in specific parts of the gut. Different encapsulation approaches qualify for protection of bioactive food components. The most commonly applied technologies are emulsification, coacervation, spray drying, spray cooling, freeze drying, fluid bed coating and extrusion technologies, but also more expensive techniques such as liposome encapsulation, and cyclodextrin encapsulation are used. When targeted release is desired in combination with adequate protection in the product, it is essential to realize which processes in the human gut can be applied to facilitate targeted release. The majority of systems that have been used in the past were either sensitive to mechanical stress, pH, or transport time variations in the gut. More recent systems take advantages of the different enzyme concentrations associated with variations in the composition of the microbiota in different parts of the gut. The latter system should receive more attention in the food industry as it allows for precise release of bioactive food components. The principle of targeted release by enzymatic activity of the microbiota is compatible with many carbohydrates that are generally regarded as safe (GRAS). Crown Copyright 2009 Published by Elsevier Ltd. All rights reserved.