The matrix of fruit & vegetables modulates the gastrointestinal bioaccessibility of polyphenols and their impact on dietary protein digestibility

•First in vivo study (pig) dealing with polyphenol bioaccessibility in the gastric tract.•Polyphenol bioaccessibility is low in stomach after F&V or extract ingestion (3.1 or 1.5%).•Plant effect: polyphenol diffusion from apple>diffusion from artichoke and plum.•Polyphenol bioaccessibility at the ileum in agreement with that for ileostomists.•The phenolic extract, but not F&V, decreased the speed and efficiency of protein digestion. Fruit and vegetables (F&V) polyphenols have numerous positive health effects, ascribed either to their antioxidant activity within the gastrointestinal tract (GIT) or to bioactivity of their absorbed metabolites. The effect of the F&V matrix on the gastrointestinal bioaccessibility of polyphenols was investigated along with its possible interaction with protein digestion. Minipigs were fed a complete meal with either cubed F&V (apple, plum, artichoke) added, or the corresponding phenolic extract (PE). Gastric and ileal chymes were kinetically collected over the postprandial period. The overall polyphenol bioaccessibility in the stomach was found to be 1.5% and 3.1% after F&V and PE consumption, respectively. The lower release rate from artichoke than from apple showed evidence of a plant effect. Flavanol monomers and glucoside conjugates were not recovered in the ileum in agreement with their absorption in the upper GIT. Interestingly, PE, but not F&V, significantly decreased the speed and efficiency of dietary protein digestion.