Cold-Pressed Pumpkin Seed Oil Antioxidant Activity as Determined by a DC Polarographic Assay Based on Hydrogen Peroxide Scavenge

Abstract

Antioxidant (AO) activity of cold pressed pumpkin (Cucurbita pepo L.) seed oil, produced from three naked and one hulled variety, was assessed using a DC polarographic assay based on a hydrogen peroxide scavenge (HPS). Results are expressed as the decrease of the anodic oxidation current of hydrogen peroxide obtained upon addition of methanolic extract of the investigated oils. Strict correlations of HPS and (1) radical scavenging capacity against the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH) (0.99), (2) the induction period estimated by a Rancimat test (0.99) and (3) total phenolic content estimated by Folin-Ciocalteu (FC) assay (0.99) were obtained. In addition, a significant correlation of HPS and the content of delta-tocopherol (0.87), squalene (0.67) and color CIE a* (-0.89) was found. Based on the results reported, the polarographic assay was found to be suitable for determination of AO activity as an indicator of the quality and oxidative stability of oil.