Antioxidant Activity of Nontocopherol Hazelnut ( <i>Corylus spp.</i> ) Phenolics

Abstract

ABSTRACT: Hazelnuts were investigated for the presence of antioxidant compounds other than tocopherol. Hazelnuts from 2 regions were extracted with methanol:water (2:1; v/v). Extracts were subjected to either acid or alkaline hydrolysis but neither improved the separation quality during high pressure liquid chromatography (HPLC) analysis. Nonhydrolyzed extracts of hazelnut had greater antioxidant activity in comparison to hydrolyzed extracts. The 1st 10 minute eluent in the HPLC had greater antioxidant activity relative to the later eluting fractions. Gallic acid, p‐hydroxyl benzoic acid, caffeic acid and/or epicatechin, sinapic acid, and quercetin were tentatively identified using HPLC.