Antioxidant Effect of Hydroxylated Diamond Nanoparticles Measured in Soybean Oil

Abstract

We investigated the antioxidant properties of detonation nanodiamond modified by Fenton's reagent. Diamond nanoparticles functionalized with hydroxyl groups were examined in soybean oil; the aim of this study was to determine their antioxidant properties by examining the effect on the lipid peroxidation process. In order to form the hydroxyl groups on the surface of the detonation diamond nanoparticles, we utilized the Fenton reaction. This reaction consisted of the oxidation of the surfaces of the nanodiamonds by the reaction of Fe²⁺ with hydrogen peroxide (H₂O₂), which is a precursor of the hydroxyl radical. The oxidation reaction of nanodiamonds via Fenton's reagent is twofold, in addition to surface oxidation it is also purified from different carbon varieties. We traced the impact of the modified nanodiamonds on the oxidation process of soybean oil. In order to hasten the process of lipid peroxidation, the soybean oil was exposure to ultraviolet (UV) light with a wavelength of 250 nm. Analysis was performed before and after 3, 6, 9, 24, 48, and 72 hours of exposure to UV light. Comparing the results of pure oil and oil with the addition of functionalized powder, we noted a significant impact of the modified nanodiamond compared to nonmodified nanodiamond on the process of counteracting the rancidity of the oil. This observation was confirmed by the peroxide value, anisidine value, Totox index, and Kreis test.

Keywords:

• Antioxidants
• diamond nanoparticles
• surface functionalization
• Fenton's reaction
• oxidation

Acknowledgment

We gratefully acknowledge the help of Dr. Urszula Skolimowska for her consultation on all analytical tests and biological research.

Funding

The research reported in this article was financially supported by the Ministry of Education, Youth and Sports in the framework of the targeted support of the “National Programme for Sustainability I” (LO1201) and the OPR&DI project “Centre for Nanomaterials, Advanced Technologies and Innovation CZ.1.05/2.1.00/01.0005.”