INFOGEST digestion remodels phenolic composition and antioxidant bioaccessibility of olive mill wastewater and alperujo extracts across fruit ripening stages.

Abstract

Olive mill wastewater (OMWW) and alperujo (OMSbP) are underexploited sources of phenolic antioxidants, but their post-digestive functional potential depends on how their phenolic profiles are affected by gastrointestinal digestion. Using the standardized INFOGEST model, we assessed digestion-induced changes in phenolic profiles and antioxidant activity of phenolic-rich OMWW and OMSbP extracts obtained at early and mature ripening stages. Folin-Ciocalteu reducing capacity, targeted UHPLC-MS profiling, and antioxidant capacity (DPPH and FRAP) were measured in the original extracts and after the oral, gastric, and intestinal phases. Digestion produced a strong phase-dependent remodeling of phenolic fingerprints, with pronounced decreases in the relative detectability of several labile compounds during oral/gastric steps and a distinct phenolic profile remaining detectable in the whole intestinal digesta. OMSbP showed higher relative detectability of several phenolic compounds during digestion than OMWW, indicating matrix-dependent behavior, and measurable antioxidant activity persisted in the intestinal digesta. Correlation and simple regression analyses revealed associations between antioxidant readouts and the relative abundances of several low-molecular-weight phenolics and phenolic acids (notably hydroxytyrosol and ferulic acid); however, these exploratory associations do not establish individual compounds as the principal determinants of antioxidant activity.