Flour of banana (Musa AAA) peel as a source of antioxidant phenolic compounds

Banana peel is an underused by-product that can be processed to obtain flour that is more easily stored for further uses. The extracts of banana peel flour exhibited a high total phenolic content (around 29 mg/g, as GAE) due to the occurrence of important amounts of flavonoid phenolics: highly polymerized prodelphinidins (around 3952 mg/kg), followed by decreasing lower contents of flavonol glycosides (mainly 3-rutinosides and predominantly quercetin-based structures, accounting for around 129 mg/kg), B-type procyanidin dimers and monomeric flavan-3-ols (jointly around 126 mg/kg). The high total phenolic content of extracts of banana peel flour is likely responsible for the very high antioxidant activity (mu M/g, as Trolox equivalents) measured by three different methods: FRAP, around 14 mu M/g; ABTS, around 242 mu M/g; and ORAC, around 436 mu M/g. All these results suggest the interest in going in depth of the good use of banana peel as a profitable source of bioactive phenolic compounds. (C) 2013 Elsevier Ltd. All rights reserved.