Standardized in vitro static digestion for diverse nutrients: understanding the consequence of food parameters on digestion kinetics

We study the influence of food parameters on the digestive kinetics of diverse nutrients throughout the upper gastrointestinal tract. For this, we use a static in vitro digestion protocol based on the standardized, consensus method recommended by the INFOGEST consortium. Briefly, the food is first mixed with simulated salivary fluids to simulate the dilution of the oral compartment. Hereafter, the gastric phase is simulated by lowering the pH to 3 and adding gastric digestive fluids and enzymes (e.g. pepsin and gastric lipase). Finally, the pH is increased to pH 7 and small intestinal fluids (e.g. bile salts) and enzymes (e.g. (chymo)trypsin, pancreatic lipase and α-amylase) are added to simulate the small intestinal phase. Samples are taken as function of digestion time to study the kinetic evolution of nutrient hydrolysis and metabolite formation throughout the upper gastrointestinal tract. Quantification of the digestive metabolites is mostly done by chromatographic techniques. Our analytical platform allows characterization of starch, lipid and protein macronutrient digestion as well as bioaccessibility of a range of micronutrients (minerals, carotenoids, etc.). Besides, we structurally characterize our digested food during digestion by the evaluation of particle size, microstructure and/or particle charge.