Chemical composition and antioxidant activity of phenolic extracts from peanut skins obtained by different industrial process

LARRAURI M; ASENSIO CM; QUIROGA PR; MARTIN MP; ZUNINO MP; ZYGADLO JA; GROSSO NR; NEPOTE V

Cordoba

Jornada; I Jornada del ICTA; 2015

FCEFyN-UNC

Peanut skins present phenolic compounds with antioxidant properties which are excellent as a source of natural antioxidants. In food products, the antioxidants have the function ofneutralizedthe action of free radicals produced by oxidation reactions. The objective of this study was to determine the chemical composition and antioxidant activity of extracts rich in phenolic compounds form peanut skins obtained by two industrial process:blanching (B) and roasting (R). Peanut skins were obtained from Argentinean high oleic peanuts (Argentina) cultivar ?Granoleico?. Crude extract (B-Cr and R-Cr) were obtained by solid-liquid extraction from peanut skins using ethanol 70% (E). B-Cr and R-CR were partitioned in four fractions with ethyl acetate (B-E and R-E) and water (B-W and R-W). Chemical composition of peanut skins was determined: fat, protein, moisture,and ash contents. Total phenolic content and free-radical scavenging activity (DPPH)were analyzed in all fractions. Statistical analysis was performed on the data(ANOVA and Fisher-LSD test). Roasting peanuts skins exhibited higher fat and ash (23.66% and 3.34%, respectively) compared with blanching peanuts skins (17.04% and 2.41%, respectively). Peanuts skinsfrom blanching process had highest total phenols content than roasting process (12.11% and 7.67%, respectively). B-Cr, B-E, and R-E exhibited higher phenolic content (674.8, 701.24,and 681.05 mg phenol/g dry matter; respectively). B-W and R-W showed the lowest total phenols content (528.68 and 283.52 mg phenol/g dry matter; respectively). The highest antioxidant activity (DPPH) was exhibited by B-E (IC50 = 1.51) followed by B-Cr, R-Cr, and R-E (IC50=2.01, IC50=2.33, and IC50=2.08, respectively). The lowest DPPH activity was shown by B-W and R-W (IC50=3.03 and IC50=5.2, respectively). Peanut skin extracts obtained from blanching process show higher total phenolic content and higher antioxidant properties measured with respect to those extract obtained by roasting process.