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Abstract
The objectives of this project were to use in vitro gastric simulation models to (1) evaluate the influence of particle size and food texture on digestion rate, (2) determine the effect of viscosity on altering the rate of gastric digestion, (3) examine the structural breakdown and protein hydrolysis of cheeses in the gastric environment, and (4) compare the efficacy of certain digestive enzyme supplements under simulated gastric conditions. A simplified dynamic gastric model that incorporates the simulation of gastric secretions, gastric peristaltic forces, and gastric emptying was created and used to investigate the effects of the gastric environment on the digestion of food with various particle sizes, textures, and rheological properties. The results indicated that regulating the particle size and food texture has the potential to alter the rate of gastric digestion. Changing the rheological properties of gastric fluid modulated the rate of gastric digestion by influencing the disintegration rate and the emptying of solids. The acidic gastric environment has been commonly thought to weaken the structure of food and encourage protein hydrolysis; while this study indicated that the gastric environment strengthened the structure of cheeses and reduced the hydrolysis of protein in certain cheeses. Various digestive enzymes supplements were also evaluated based on their efficacy to degrade casein and food mixture, and the results demonstrated significant improvements in the digestion of food with commercial enzymes by releasing greater amounts of bioaccessible nutrients. The study proves that dynamic gastric model is an effective tool to study the behavior of food and enzyme under gastric conditions providing more comprehensive and accurate information as compared to static models.