Analysis of the Spatiotemporal Digestion Characteristics of Pine Pollen Processed by Different Methods in Middle-Aged Adults Using an In Vitro Digestion Model System

This study utilized a proprietary dynamic biomimetic digestion reactor to compare the differential behaviors of broken-wall pine pollen (PB), whole-wall pine pollen (WPB), and pine pollen wall extract (T) during simulated gastrointestinal digestion and colonic fermentation in middle-aged individuals. Morphological changes were observed using scanning electron microscopy, and glucose release, enzyme activity, intestinal gas composition, and gut microbiota structure were dynamically monitored. The results indicate that cell wall disruption significantly accelerated structural breakdown, resulting in the highest glucose release, superoxide dismutase, and lipase activities during the gastric and small intestinal phases, as well as the highest activity of alkaline phosphatase and H2 and CO2 gases during colonic fermentation. Due to its intact outer wall, WPB exhibited more robust and sustained enzyme activity and gas production, which was particularly beneficial for maintaining catalase activity in the descending colon of women. The T group demonstrated exceptional glucose and flavonoid release during digestion, but exhibited low SOD activity in the colon and a specific increase in H2S and VOCs in the descending colon. Furthermore, all three groups inhibited Escherichia-Shigella, with gender differences observed in the regulatory patterns. This study elucidates the processing-driven differential regulatory characteristics of pine pollen on in vitro intestinal fermentation behaviors, providing an in vitro experimental basis for the development of differentiated pine pollen products tailored to the needs of different populations.