New Perspectives on the Delivery of Nutrients and Bioactive Compounds through Gastric Restructuring of Foods.

All foods come from living organisms in which macromolecules such as proteins and polysaccharides are assembled into complex hierarchical structures. Many of the nutrients and bioactive compounds are contained within these structures, from which they must be liberated and converted into an absorbable form during digestion. It has been realized that the modification of these structures during digestion plays a key role in determining the bioaccessibility and rates of absorption of bioactive compounds. The concept of "food structure design" has been applied to developing food structures to control the perception of fat, salt, and sugar in food products, but the role of food structure as a variable in nutrient and bioactive delivery is relatively unknown. Understanding the architecture and structures of foods and how they interact within the physiological environment of the GIT could lead to new foods that provide optimal bio-accessibility and absorption of bioactive compounds. Recent work at our institute has demonstrated the importance of understanding the state and structures of food materials in the environment of the GIT, particularly in the stomach, and the critical role of 'modified' structures on the kinetics of the release of nutrients and bioactive compounds from the food matrix (e.g., the rate, extent and type of released nutrients), gastric emptying and subsequent digestion of foods in the small intestine. The use of dynamic in vitro digestion in combination with in-vivo studies has provided new insights into the structural dynamics of complex food systems and subsequent interactions of food components during the gastrointestinal transit.