| The rate of bolus disintegration in the stomach is important in determining gastric emptying, which has shown to be directly correlated with post-food consumption blood glucose levels and satiety. The objectives of this study were to examine the effect of various factors on bread bolus disintegration rate, including flour type, gastric juice components (acid and enzymes), hydrodynamic forces, saliva level, and presence of alpha-amylase in saliva. The kinetics of bolus disintegration were determined by measuring the mass retention of boluses and fitting their disintegration profiles to an exponential model.;Bread was used as a test food and samples of 100% wheat, 100% rye, 100% barley, 50% almond meal 50% wheat flour, and white sourdough bread were used to determine the influence of bread composition on bolus disintegration in gastric juice. Artificially masticated bread was mixed with simulated saliva to form a bolus. The boluses were soaked in simulated gastric juice for 120 min. Sample mass was measured at 10-15 min intervals and mass retention ratio was calculated as the normalized mass at each time interval.;The mass retention kinetics during static and agitated soaking were shown to follow three distinct profiles: exponential, sigmoidal, and delayed sigmoidal, depending on the bolus bread type. These differences in profiles were attributed by varying levels of water absorption in the different bread types, caused by the variations of bread structure and moisture content. The hydrodynamic forces produced by agitating the gastric juice surrounding the bolus or the addition of salts, mucin, and acid did not produce a significant effect on bolus disintegration for all bread types when compared to the bolus disintegration in water. The main component of gastric juice responsible for bread bolus disintegration was pepsin. Increasing the bolus saliva level increased the moisture content and decreased the cohesive forces in the bolus, increasing the disintegration rate during static soaking. These changes could have been caused by the increase of water inside the food matrix, or by the softening effect of alpha-amylase, as it was shown to have a significant effect on the bolus texture and also caused an increase in bolus disintegration.;Knowledge of the driving factors behind bolus disintegration is important to help understand the overall bolus breakdown during gastric digestion. Since the breakdown of bread boluses will control the gastric emptying and glucose response after bread consumption, an ability to understand and control this breakdown is important for many nutritional and medical applications. |
