Quantifying intestinal lipolysis with MRI and TD-NMR: Proof of concept using dairy cream digested in vitro

Understanding lipid digestion is crucial for promoting human health. Traditional methods for studying lipolysis face challenges in sample representativeness and pre-treatment, and cannot measure real-time lipolysis in vivo. Thus, non-invasive techniques like magnetic resonance imaging (MRI) need to be developed. This study assessed the MRI water-fat separation method for monitoring in vitro intestinal digestion of dairy cream, supported by high-performance thin-layer chromatography (HP-TLC) and time-domain nuclear magnetic resonance (TD-NMR). A clear distinction was found between the T₂ of undigested lipids (∼120 ms) and lipolytic products (0.1-15 ms). The short T₂ of lipolytic products likely results from semi-crystalline structures formed with bile salts. While MRI methods cannot detect such fast-relaxing protons, it effectively quantified lipolysis by tracking the residual undigested lipids, showing high correlation with HP-TLC results (R² = 0.93 and 0.95 for 13-s and 6-min MRI methods, respectively). The rapid 13-s MRI method offers strong potential for future in vivo applications.