Avaliação da atividade antioxidante de farinha obtida da casca do umbu (Spondias tuberosa Arr.)

Abstract

The umbu fruit (Spondias tuberosa) is native to the Caatinga biome and has demonstrated excellent antioxidant potential; however, it is still little explored in its entirety. The use of by-products such as fruit peels is a sustainable strategy for adding value. The objective of the study was to produce umbu peel flour and evaluate its antioxidant properties. The umbu peels were dried in a ventilated oven (55°C in 24h) to produce the flour. The flour extracts were obtained by the ultrasound-assisted method, with simple solvents (ethanol and acetone). The extracts were used to determine total phenolic compounds (TPC), identification of phenolic compounds by high performance liquid chromatography (HPLC) and antioxidant tests of total antioxidant capacity (TAC), reducing power, ability to scavenge the 2,2´-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical and 1,1-diphenyl-2-picrylhydrazil (DPPH) radical. The results showed a TPC of (21.79 mg EAG/g ± 0.70) for the acetone extract and (21.08 mg EAG/g ± 0.36) for the ethanolic extract. The compounds gentisic acid, quercetin, vanillin, and gallic acid were identified, where the latter two were not identified in the acetone extract. In the evaluation of antioxidant activity, the acetone extract presented CAT of (158.25 µg/g ± 8.45) and the ethanolic extract of (7.72 µg/g ± 0.11); reducing power activity was identified only in the ethanolic extract (33.91% ± 1.63); in ABTS the acetone extract obtained (3.19 mM eq TE/g ± 0.10) and (2.63 mM eq TE/g ± 0.03) for the ethanolic and finally, the DPPH resulted in (10.02 mM eq TE/g ± 0.13) for acetone and in the ethanol extract (7.58 mM eq TE/g ± 0.08). It is concluded that umbu peel flour extracts contain bioactive substances with antioxidant activity, demonstrating their potential for use for various purposes