The intelligent delivery systems for bioactive compounds in foods : Physicochemical and physiological conditions, absorption mechanisms, obstacles and responsive strategies

Background: Bioactive natural compounds have received considerable attention due to their health benefits, including anti-oxidant, anti-cancer, anti-diabetes and cardiovascular disease-preventing functions. However, the stability of these sensitive compounds can be influenced by unfavourable environmental conditions during processing and storage. In addition, delivery of bioactive compounds via the oral route is restricted by various physiological barriers, including a harsh pH, gastrointestinal enzymes, the mucus layer, and the epithelium. Intelligent delivery systems are a promising method to protect bioactive molecules from degradation and improve their bioavailability. Scope and approach: We have demonstrated the physicochemical and physiological GI conditions. The structural composition of the epithelium and transport mechanisms of bioactives and nanoparticles across the intestinal epithelium were discussed. The effects of enhanced aqueous solubility, stability, bioaccessibility and bioavailability after encapsulation were illustrated. Furthermore, novel intelligent carriers that are responsive to the oral route, pH, enzymes and cell receptors were also discussed. Key findings and conclusions: This comprehensive multidisciplinary review provides useful guidelines for the application of bioactive compounds in the food industry. Intelligent carrier systems are designed to improve the low solubility, poor stability and low permeability of the gastrointestinal tract, and they have the potential to improve oral bioavailability.