Optimization of extraction of phenolic antioxidants from peanut skins

This work was conducted to optimize the extraction conditions for the best recovery of antioxidant compounds from peanut skins. The extracts from the peanut skins were obtained by different extraction methods. The extraction conditions were: different ethanol proportions as the solvent (0, 30, 50, 70 and 96% v/v in distilled water), different peanut skin particle sizes (0–1, 1–2 and 2–10 mm and non-crushed skins), different proportions of solvent/skins (20, 30, 40, 50 and 60 ml g⁻¹), different extraction times (by maceration and shaking) and different numbers of extractions. The different extracts obtained under different extraction conditions were compared with special regard to yield, total phenolic compounds and radical scavenging activity. The results showed that the best delivery of phenolic compounds was reached using 70% ethanol, non-crushed peanut skins, ratio of solvent/solid of 20 ml g⁻¹, at 10 min shaking and three extractions. The maximum yield of 0.118 g g⁻¹ was recorded for phenolic compounds when extracted at the optimum conditions. Copyright © 2004 Society of Chemical Industry