Bioactive Potential, Gastrointestinal Bioaccessibility, and Preliminary Safety Assessment of a Phenolic-Rich Coffee Pulp (Coffea arabica) Extract

Background/Objectives: Coffee pulp (Coffea arabica) is an agroindustrial byproduct of coffee production and has high potential as a source of bioactive compounds.

Methods

In this study, a coffee pulp extract was characterized by determining its total polyphenol content (TPC), condensed tannins (CT), and total flavonoids (TFC), as well as its antioxidant activity, inhibition of α-amylase and α-glucosidase, stability during in vitro gastrointestinal digestion, and toxicity in Artemia salina.

Results

The extract exhibited a TPC of 90.33 mg GAE/g of extract, a TFC of 60.48 mg CE/g of extract, and a CT of 27.27 mg PC1eq/g of extract. Antioxidant activity was measured as follows: DPPH (105.41 mg TE/g of extract), ABTS (69.41 mg TE/g of extract), TAA (325.11 mg TE/g of extract), and FRAP (106.03 mg TE/g of extract). The extract inhibited α-amylase by 20.67% and α-glucosidase by 34.69% at 1000 µg/mL. In vitro digestion reduced phenolic compounds and antioxidant activity, with a low proportion of condensed tannins considered absorbable, while polyphenols could not be detected in the dialysis. On the other hand, the median lethal concentration (LC50) in A. salina was > 1000 µg/mL, thus considered non-toxic.