Prebiotic effect, bioactive compounds and antioxidant capacity of melon peel (Cucumis melo L. inodorus) flour subjected to in vitro gastrointestinal digestion and human faecal fermentation

Melon peels are by-products derived from food processing industries, representing potential sources of new ingredients in particular dietary fibre and phenolic compounds, which in synergy could exert beneficial effects on human health. The objective of this study was to evaluate the accessibility of bioactive compounds from melon peels throughout gastrointestinal digestion and evaluate their prebiotic effect when submitted to in vitro human faecal fermentation. Melon peels flour obtained from solid fraction showed an increase in antioxidant capacity at the gastric and intestinal phase, which was corroborated by the total phenolic content (126.91%) increase and the identified individual phenolics (tyrosol, luteolin-6-glycoside, chlorogenic and caffeic acids). Also, melon peels flour positively impacted the gut microbiota diversity, showing a similar ratio of Firmicutes/Bacteroidetes compared to the positive control (FOS) and promoted the production of short-chain fatty acids, mainly acetate > propionate > butyrate. Thus, these findings demonstrate that melon peels have antioxidant and prebiotic potential attributed to the phenolic compounds and the production of beneficial fatty acids, which could improve human gut health.