Phenolic compounds, bioactivity, and bioaccessibility of ethanol extracts from passion fruit peel based on simulated gastrointestinal digestion

Passion fruit peel, a potential source of bioactive compounds, has been used as food stabilizing agent. However, the phenolic composition and bioactivity of passion fruit peel have rarely been reported. The effects of simulated gastrointestinal digestion on the bioactive components, bioactivity and bioaccessibility of passion fruit peel ethanol extracts (PFPE) were investigated using high performance liquid chromatography-tandem mass spectrometry analysis (quasi-targeted metabolomics). Phenols (178) were identified, of which 25 inhibited alpha-glucosidase activity. The stabilities of PFPE phenols were significantly affected by pH changes and digestive enzymes during simulated digestion. The 1,1-diphenyl-2-picrylhydrazyl free radical scavenging capacity and ferric ion reducing antioxidant power were decreased by 32% and 30%, respectively, while 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) free radical scavenging capacity increased by 17%. Alpha-glucosidase inhibition decreased with decreased PFPE phenolic content. Therefore, passion fruit peel could be considered a source of natural antioxidants and alpha-glucosidase inhibitors.