Dietary fibre concentrates from avocado and mango by‐products; antioxidant capacity and polyphenols evaluation by HPLC‐IDA‐EPI‐MS

Abstract

SummaryPhenolics bound to dietary fibres (DF‐PCs) represent a valuable source of antioxidants that are often wasted. DF‐PCs can be obtained as residues from conventional extraction processes of PCs derived from agro‐industrial by‐products. This study aimed to characterise DF‐PCs generated after the PC extraction process from the avocado peel (AP), mango peel (MP) and husk mango seed (testa) (MT), with a focus on solid residue or concentrated fibre (APFT: avocado peel fibre; MPFT: mango peel fibre; MTFT: mango testa fibre). The by‐products were evaluated under both non‐defatted and defatted conditions before simulating the PC extraction process. PCs were quantified (TPC) and identified (HPLC‐IDA‐EPI‐MS). Their antioxidant activity (AA) was determined (ABTS+, DPPH* and FRAP). Among the evaluated fibres, non‐defatted AP and defatted MP and MT exhibited the highest TPC content (22.64 ± 0.3, 37.31 ± 1.78 and 6.07 ± 0.08 mg GAE/g), respectively. Using the DPPH* assay, all fibre concentrates showed lower AA compared to the by‐products. Using FRAP assay, defatting gave the largest activity for mango samples. HPLC‐IDA‐EPI‐MS analysis of PC profiles resulted in the presence of 62 PC compounds in the fibre concentrates. These DF‐PCs, with a significant content of PCs, may be relevant as functional ingredients for food production.