Obtaining and characterization of anthocyanins from Euterpe oleracea (açaí) dry extract for nutraceutical and food preparations

ABSTRACT

Abstract The main constituents of the Euterpe oleracea Mart., Arecaceae, fruits (açaí) are anthocyanins. This paper aimed to standardize the extraction process and characterize an anthocyanin-rich dry extract obtained from this fruit. A 23 full factorial design was used. The volumes of ethanol 92% and acetic acid and the extraction time were used as factors. Total solids and anthocyanins content were used as feedback. The dry extract was obtained by freeze-drying. The content of anthocyanins was determined spectrophotometrically. Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimeter, Thermogravimetry, Scanning Electron Microscopy, and Atomic Absorption Spectrometry were used for characterizingthe dry extract. The DPPH method was used for evaluating radical scavenging activity. The extraction conditions were established. The most influent factor was the volume of acetic acid. The dry extract moisture content was equal to 1.39 ± 0.25%, the evaporation residue 97.25 ± 1.28%, total ashes 0.62 ± 0.12%, and the anthocyanin content was 61.75 ± 3.28%. The elemental composition shows the presence of manganese 4.85 ppm, iron 1.62 ppm, zinc 0.05, copper 1.38 ppm, calcium 1.01 ppm, cadmium 0.003 ppm, nickel 0.37 ppm, and lead 0.38 ppm. The dried extract IC50 estimated by the radical scavenging assay with DPPH was 31.25 ± 2.31 ppm. The optimal extraction conditions were the volume of ethanol 92% 400 ml; volume of acetic acid 75 ml; an extraction time 4 h.