Chemical composition and antioxidant activity of phenolic extracts and their purified fractions obtained from peanut skins

LARRAURI M; ASENSIO, C.; QUIROGA PR; GROSSO NR; ZUNINO MP; ZYGADLO, J.A.; NEPOTE V

Chicago, Illinois

Congreso; IFT 13 - Annual Meeting and Food Expo; 2013

Institute of Food Technologists - IFT

Peanut skins are rich in phenolic compounds with antioxidant property that can be a source of natural antioxidant to be used in food for increasing its shelf life and stability. The objective of this study was to determine the chemical composition and antioxidant activity of phenolic extracts and purified fraction obtained form peanut skins. Peanut skins were obtained by blanching process from ?Runner? peanuts (Argentina). Crude extract (B-Cr) was obtained by solid-liquid extraction from peanut skins using ethanol 70%. B-Cr was partitioned in two fractions with ethyl acetate (B-EA) and water (B-W). B-EA was separated by column chromatography (CC) packed with Sephadex LH-20 using ethanol as elution solvent in three new fractions: yellow (Y), purple (P) and brown (B). Total phenolics, chelating activity Fe+2, DPPH analysis and hydroxyl radical-scavenging were determined in all fractions. Statistical analysis was performed on the data (ANOVA and Fisher-LSD test). Fractions Y, P, and B exhibited higher phenol content and antioxidant activity thant B-Cr, B-EA, and B-W. Significant correlations were observed between total phenolic, chelating activity Fe+2, and DPPH values. P and B had the highest phenolic content (863.72 and 763.73 mg phenol/g dry matter, respectively), chelating activity Fe+2 (IC50: 25.73 and 58.26, respectively), and DPPH activity (IC50 = 1.03 and 0.65, respectively). Fraction Y had the lowest phenolic content (374.38 mg phenol/g dry matter), chelating activity Fe+2 (IC50 = 91.53) and DPPH activity (IC50 = 4.7), but showed the best hydroxyl radical-scavenging capacity (IC50 = 0.93). Purification process of peanut skin extracts increased the antioxidant property in peanut skin extracts. Crude extract and its purified fractions of peanut skins are a potential natural antioxidant that can be used to preserve and prolong shelf-life of food products.     Industry Relevant Information: The shelf-life of food products could be prolonged by the addition of natural preservatives. Peanut skins are a waste from blanched processing of peanut kernels. Phenolic compounds extracted from peanut skins showed remarkable antioxidant activity. These compounds from peanut skins have a considerable potential in the food industry as natural antioxidant to be used in fatty food products to substitute synthetic ones.