Properties of Gastric Chyme from Pigs Fed Cooked Brown or White Rice

Specific effects of food processing on food digestion remain to be clearly established. The objective of this study was to determine the effect of rice processing (cooked brown and white rice) on the rheological properties, chemical composition (water, starch, fiber, protein) and pH of gastric chyme in pigs over a two hour post-ingestion period in the proximal and distal regions of the stomach. Results showed the distal region having a higher moisture content, lower pH, and lower viscosity compared to the proximal region for both brown and white rice. Starch content was significantly affected by the region x time x rice interaction (p = 0.0259), protein content by both the rice x time (p = 0.0143) and the region x time (p = 0.0181) interactions, and total dietary fiber by rice type (p = 0.005). Rice digesta behaved as a gel, with G' (42288-1911 Pa) greater than G" (6307-360 Pa). The extent of particle breakdown for brown and white rice was different. Overall, the results indicated a connection between food processing and food breakdown during gastric digestion. These findings have implications in the management of nutrient absorption and satiety control that can be used in future food design.