  The peristaltic motion of the stomach walls combines with the secretion of
enzymes to initiate the process that breaks down food. Computational modelling
of this phenomenon can help reveal the details that would be hard to capture
via in-vivo or in-vitro means. In this study, the digestion of a liquid meal
containing protein is simulated in a human-stomach model based on imaging data.
Pepsin, the gastric enzyme for protein hydrolysis, is secreted from the
proximal region of the stomach walls and allowed to react with the contents of
the stomach. The jet velocities, the emptying rate, and the extent of
hydrolysis are quantified for a control case, and also for three other cases of
reduced motility with varying peristaltic amplitudes. The findings quantify the
effect of motility on the rate of food breakdown and emptying, and correlate
the observations with the mixing in the stomach induced by the antral
contraction waves.
