Phenolic compounds and antioxidant capacity of canned pequi pulp (Caryocar spp)

Abstract

The aim of the study was to evaluate the extracts, canning liquid (CL) and phenolic acids fractions of canned pequi pulp concerning the phenolic contents and antioxidant capacity (AC). The alcoholic extracts (ALCE) and aqueous (AQE) were obtained by sequential extraction and CL was only filtered. The fractions rich in free phe­nolic acids (FPA), soluble esters (SPA) and insoluble (IPA) were isolated with solvents, hydrolysis and acidifi­cation. The total phenolic content (TPC) and its composition by liquid chromatography were determined. AC was measured by DPPH^·· methods (2,2-diphenyl-1-picrylhydrazyl) and β-carotene/linoleic acid system. It was found that the extracts and CL of canned pequi have small amount of TPC (18.06 mg GAE/ 100 g), however fractions have significant amount (1134.75 mg GAE/ 100 g), with special focus on FPA. The ρ-coumaric acid was the major phenolic constituent of the extracts, and especially of fractions. It was also detected in CL, showing the migration of this phenolic into surrounding liquid. The extracts showed by DPPH^·· method, IC₅₀ values of 533.62, 1376.28 and 1542.74 µg/mLfor ALCE, AQE and CL, respectively, and oxidation inhibition percentage (% OI) inferior than the butylated hydroxytoluene (BHT) synthetic antioxidant by β-carotene/linoleic acid system. The fractions showed high AC by DPPH^·· method and OI% higher than BHT in all tested concentrations. The study shows that extracts and mainly the canned pequi fractions have phenolic with good AC, which are important for the promotion of health.