The effect of consumption temperature of whole milk on in vitro gastric digestion using MRI
Résumé
This study utilized Magnetic Resonance Imaging (MRI) to investigate the behaviour of whole fat milk at varying temperature during semi-dynamic in vitro gastric digestion. The experimental protocol was designed to closely reproduce the gastric temperature profiles observed in humans after consumption of milk at 4°C, 37°C, and 60°C. Consuming milk at 4°C significantly postponed the onset of protein coagulation during the gastric phase compared to both 37°C and 60°C. MRI lipid quantitative analyses also showed that the fat-rich particles tended to float the top of the digesta in a process similar to creaming, and after a delay that seemed to increase in the order: milk at 4°C < milk at 37°C < milk at 60°C (no floating particles within 2h). However, the released quantities of free amines in collected samples, which indirectly reflect the activity of pepsin, did not significantly vary with the milk temperature. Our findings highlight the significance of consumption temperature in modulating the structural reorganisation of whole milk during gastric digestion and illustrate some of the capabilities offered by MRI to investigate such phenomena. They also open questions on the potential consequences of milk consumption temperature on the nutrient delivery rate into the small intestine and their further breakdown and absorption kinetics.