Tracking the digestive performance of different forms of dairy products using a dynamic artificial gastric digestive system

Abstract

This study aimed to explore the digestive behaviour of different forms of dairy products using an independent-developed artificial gastric digestion system (AGDS). It was found that the pH of UHT milk, yogurt and cheese increased to 6.5, 4.2 and 5.7, respectively, at the beginning of gastric digestion, while the value of cheese showed slower decreased rate than the other dairy products with the time extension. Protein in liquid (milk) and semi-liquid (yogurt) dairy was obviously hydrolyzed in the simulated stomach, whereas, the proteins were coagulated and slow-degraded in solid product (cheese) under gastric conditions. The fat globule quickly released from the UHT milk and distributed relevant uniform alongside the protein particles, while it wrapped in protein network and no obviously coalescence was found in yogurt. The fat in the cheese was slower release and lots of free fat aggregated in the continuous phase at the end of digestion. Results indicated that the artificial stomach could provide useful information for the design of dairy and other food matrices linking the structure and controlled release of nutrients in the stomach.