Microbial catabolism of coffee pulp (poly)phenols during in vitro colonic fermentation

Coffee pulp is a by-product characterized by its richness in phenolic compounds. This study examined the catabolism of (poly)phenols in digested coffee pulp flour (CPF) and extract (CPE) during in vitro colonic fermentation. After a simulated gastrointestinal digestion, samples were fermented using human microbiota and (poly)phenol transformations were analyzed by UHPLC-ESI-MS/MS. Digested CPF and CPE contained high amounts of phenolic acids, notably 3′,4′-dihydroxycinnamic (99.7–240.1 μmol 100 g−1) and 3,4-dihydroxybenzoic acid (174.1–491.4 μmol 100 g−1). During the in vitro fecal fermentation, phenylpropanoic acids (1.5- to 2.6-fold), phenyl-γ-valerolactones (1.3- to 23-fold), phenylvaleric acids (1.1- to 2-fold) and benzene derivatives (1.5-fold) increased; while benzoic and cinnamic acids, cinnamoylquinic derivatives, flavonols, benzaldehydes and diphenylpropan-2-ols decreased. The (poly)phenols in CPF were catabolized more slowly than in CPE, suggesting protection of the fibrous matrix against phenolic degradation. Coffee pulp may be a promising food ingredient rich in (poly)phenols contributing to the prevention of intestinal diseases.

This research was funded by the COCARDIOLAC project from the Spanish Ministry of Science and Innovation (RTI 2018-097504-B-I00) and the Excellence Line for University Teaching Staff within the Multiannual Agreement between the Community of Madrid and the UAM (2019-2023). It was also supported by the National Recovery and Resilience Plan (NRRP), Mission 4 Component 2 Investment 1.3 - Call for tender No. 341 of 15 March 2022 of Italian Ministry of University and Research funded by the European Union – NextGenerationEU; Award Number: Project code PE00000003, Concession Decree No. 1550 of 11 October 2022 adopted by the Italian Ministry of University and Research, CUP D93C22000890001, Project title “ON Foods - Research and innovation network on food and nutrition Sustainability, Safety and Security – Working ON Foods”. Silvia Cañas received funding from the UAM-Santander grants program for the mobility of young researchers. Vanesa Núñez-Gómez holds a Margarita Salas contract funded by the Spanish Ministry of Universities and the European Union - NextGenerationEU.

Peer reviewed