An engineering understanding of the small intestine

Abstract

The main objective of this research was to understand phenomena occurring during food digestion and nutrients absorption in the small intestine from an engineering perspective. Intestinal flow and mixing processes were simulated using a dynamic in vitro Small Intestine Model (SIM). Of particular interest was to study the effect that mixing and food formulation has on glucose absorption and starch hydrolysis. Results showed the effect of segmentation motion on nutrient delivery to the intestinal wall as a consequence of changes in the mass transfer coefficient. This is most likely due to the increased mixing in the SIM. Experiments of starch digestion with and without the presence of guar gum have shown that viscous fibres reduce the rate of starch digestion and glucose absorption by impairing mixing and reducing diffusion within the fluid. Similarly, use of particulate systems demonstrated a significant effect on the delivery rates. Flow visualization techniques used for studying flow paths in the SIM showed that this in vitro model reproduces the characteristic flow events and mixing found in the small intestine in vivo. This research provides insights into the role of mixing on enhancing mass transfer on the course of digestion-absorption processes and also the action of viscous polysaccharides on the delay of glucose absorption in the small intestine. The end findings resulted in a better understanding of the factors which control the development of new functional food that could be applied both in academia and industry