Chemical characterization and antioxidant properties of fractionsseparated from extract of peanut skin derived from differentindustrial processes

LARRAURI MARIANA; ZUNINO M.PAULA; ZYGADLO JULIO A.; GROSSO NELSON R.; NEPOTE VALERIA

Industrial Crops and Products

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 94 p. 964 - 971

0926-6690

Peanut skins are a natural source of phenolic compounds with antioxidant activity and potential utility asfood preservatives. The purpose of this study was to determine the chemical composition and antioxidantactivities of extracts and purified fractions obtained from peanut skins prepared by blanching and roast-ing processes. Peanut skins from blanching and roasting processes were used to obtain crude extracts.These crude extracts were purified by solvent partition with n-hexane, ethyl acetate, and water. The ethylacetate fraction obtained from blanched peanut skins was separated in a column packed with SephadexLH-20 and separated into three new fractions of different colors: yellow, purple, and brown. The extrac-tion yield, total phenols and flavonoids, scavenging activity towards different radicals (DPPH, hydroxyl,and superoxide anion), ferrous ion chelating activity, and accelerated sunflower oil oxidation were eval-uated in crude extracts and purified fractions. The peanut skin fraction compounds were analyzed byHPLC?ESI-MS/MS. The extracts obtained from blanched peanut skins displayed a higher phenolic con-tent (672.40 mg GAE/g) than those prepared from roasted peanut skins (416.92 mg GAE/g). Purificationusing solvent partition with ethyl acetate and column chromatography increased total phenolic contentand antioxidant activity of peanut skin extracts. Fractions with higher total phenolic contents were asso-ciated with higher scavenging activities towards DPPH and superoxide anion radicals, and higher ferrousion chelating activity. The yellow fraction exhibited higher flavonoid content and showed higher hydroxylradical scavenging activity. In the accelerated sunflower oil oxidation test, peroxide values were lowerin the color fraction samples. The main compounds present in peanut skin color fractions were phenolicacids, flavonoids, and stilbenes. The purified fractions of peanut skins displayed antioxidant propertiesand reduced peroxide formation in sunflower oil. These fractions could be used as a natural antioxidantin food products.