ANTIOXIDANT PROPERTIES OF PECAN KERNELS

Abstract

Pecan kernels from cvs.: Kanza, Nacono, Pawnee, Shawnee, and Desirable were collected and analyzed for their antioxidant capacity (AC), total phenolic content (TP), condensed tannin content (CT), and High-Performance Liquid Chromatography (HPLC) phenolic profile. Values obtained for antioxidant capacity assessed with the Oxygen Radical Absorbance Capacity (ORAC) assay (ACORAC) followed the trend ‘Kanza’ > ‘Nacono’ ≥ ‘Shawnee’ ≥ ‘Pawnee’ > ‘Desirable’. Similar trends were observed for TP, CT, and AC measured with the DPPH assay. ‘Kanza’ had the greatest ACORAC value and ‘Desirable’ the least, with 817 and 372 µmoles of trolox equivalents/g defatted kernel, respectively. Cultivars differed greatly in their phenolic content; CT ranged from 23 to 47 mg catechin equivalents/g defatted kernel and TP from 62 to 106 mg chlorogenic acid equivalents/g defatted kernel. After basic-acid hydrolysis, gallic and ellagic acids were identified, suggesting the presence of hydrolyzable tannins. The presence of phenolic compounds with high antioxidant capacity indicates that pecan kernels should be added to the list of important dietary sources of antioxidants.