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

Phenolics 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

Hydroalcoholic extracts from the bark of Quercus suber L. (Cork): optimization of extraction conditions, chemical composition and antioxidant potential

Cork is the bark of the tree Quercus suber L. which ï¬ nds use in diverse applications. However, a signiï¬ cant percentage is still rejected and burned for energy production, despite containing valuable molecules for materials processing and with important biological activities. Herein, the optimization of the extraction process to obtain these molecules, using mild solvents and conditions, is described within a bioreï¬ nery perspective. The extracts were obtained by direct contact solvent extractions with water, ethanol and its mixtures for different time and temperatures, and evaluated for chemical composition, total phenolic content (TPC) and antioxidant properties [by DPPH radical scavenging, ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) assays]. The results showed that the extraction process is accelerated and higher yields are achieved with the increase in temperature without chemical degradation or compromising the antioxidant capacity. For all solvents, at reï¬ ux temperature, more than 90% of the extractable material is obtained within 6 h (80% within 1 h). The highest TPC and antioxidant capacity are observed for the extracts obtained with mixtures of water and ethanol of similar volumes. The antioxidant capacity measured by DPPH, FRAP and TEAC assays was found to be proportional to the extract TPC, while ORAC is favored for higher percentages of ethanol on the extracting solvent. The main constituents of these extracts are the ellagitannins, vescalagin, castalagin and b-O-ethylvescalagin, along with other phenolic acids (mainly ellagic and gallic acids) and various ï¬ avonols. The extracts stability was monitored up to 1 year of storage with neither reduction in the antioxidant capacity nor chemical degradation. These results show that extracts with strong antioxidant potential and high content of bioactive molecules can be obtained from the processing of waste streams. Cork is a sustainable forest product and the development of new ï¬ elds of application contributes toward a zero waste cycle for a complete material bioreï¬ nery.The authors are grateful to Amorim Cork Composites for providing the cork powder and for the financing provided by the COMPETE/QREN/EU funding program through project BioActiveCork (QREN FCOMP-01-0202-FEDER-005455). Ivo M. Aroso and João P. Fernandes Fig. 6 Comparison between fresh and 1 year stored extracts for a TPC and b DPPH scavenging capacity Wood Sci Technol123 acknowledge the financial support from FCT through grants SFRH/BD/42273/2007 and SFRH/BD/73162/2010, respectively. Funding was also granted from the European Union’s Seventh Framework Programme (FP7/2007–2013) under Grant Agreement No. REGPOT-CT2012-316331-POLARIS and from Project ‘‘Novel smart and biomimetic materials for innovative regenerative medicine approaches (Ref.: RL1 - ABMR - NORTE-01-0124-FEDER-000016)’’ co-financed by North Portugal Regional Operational Programme (ON.2 – O Novo Norte), under the National Strategic Reference Framework (NSRF), through the European Regional Development Fund (ERDF). Conflict of Interest: The authors declare that they have no conflict of interest.info:eu-repo/semantics/publishedVersio