Abstract:This study was conducted to investigate the changes of trehalose-based maltoheptaose (N-G7) before and after encapsulation in simulated digestive fluid and in vitro fermentation. The mass ratio of N-G7 and the sugar composition of N-G7 microspheres (ALG-Ca) in the solution before and after digestion were analyzed by in vitro digestion models of oral, stomach, and small intestine. The fermentation characteristics of microspheres were evaluated by in vitro fermentation technology. The changes in pH values, OD600, gas production, and short-chain fatty acid (SCFA) content at different time points were detected, and their effects on the composition of human intestinal microbiota were studied. The results showed that N-G7 was almost not hydrolyzed in the oral digestion for 2 minutes and in the highly acidic gastric environment. However, the hydrolysis rate of N-G7 reached 82.70% after intestinal digestion. Encapsulation with different concentrations of calcium alginate (1%, 2%, 3%) formed microspheres that retained approximately 80% of N-G7 reaching the colon. During in vitro fermentation, the pH value and OD600 of each experimental group decreased and increased continuously with time. The gas production and carbon source consumption rate in the 2% ALG-Ca group were the lowest among all groups from 0 to 6 hours, followed by a gradual increase, indicating that the fermentation system of N-G7 after encapsulation belonged to slow fermentation. Compared with the control group, the 2% ALG-Ca group produced a large amount of SCFA and changed the composition of intestinal microbiota, which was more conducive to the growth of probiotics.
