Digestion processes and the need for <i>in vitro</i> and mathematical models

The complexity of modern food matrices, including functional foods, and encapsulated delivery systems, challenges the prediction of nutrient fate, bioaccessibility, and release kinetics during gastrointestinal digestion. To address this, physiologically relevant in vitro digestion (IVD) models are used to systematically investigate these processes. Static, semi-dynamic, and dynamic approaches enable the assessment of nutrient release, matrix–enzyme interactions, and bioaccessibility across simulated digestive phases. Mathematical modeling of digestion kinetics using empirical models allows the estimation of rate constants, diffusion behavior, and digestible fractions. Recent advances, including miniaturized platforms, real-time monitoring, and data-driven approaches, further improve analytical resolution and predictive capacity, revealing complex digestion patterns and matrix-dependent enzyme accessibility. Integrating dynamic IVD systems with quantitative modeling provides deeper insight into nutrient release mechanisms and supports the development and optimization of functional foods and delivery systems under physiologically relevant conditions.