Simulated digestion, dynamic changes during fecal fermentation and effects on gut microbiota of Avicennia marina (Forssk.) Vierh. fruit non-starch polysaccharides

•Avicennia marina fruit non-starch polysaccharides (AMFPs) were obtained and analyzed.•Dynamic changes of AMFPs during simulated digestion and fermentation were revealed.•AMFPs were not digested by the digestive juice but were utilized by gut microbiota.•Beneficial microbiota, such as Mistuokella, and Prevotella were obviously increased.•Harmful bacteria were obviously inhibited and SCFA levels were obviously promoted.