Absolute kinetics of peroxidation and antioxidant protection of intact triglyceride vegetable oils

Yafang Guo; Albert Pina; Simone Gabbanini; Luca Valgimigli

doi:10.1016/j.foodchem.2024.139289

Absolute kinetics of peroxidation and antioxidant protection of intact triglyceride vegetable oils

Food Chem. 2024 May 3:452:139289. doi: 10.1016/j.foodchem.2024.139289. Online ahead of print.

Authors

Yafang Guo¹, Albert Pina¹, Simone Gabbanini², Luca Valgimigli³

Affiliations

¹ University of Bologna, Department of Chemistry "G. Ciamician", Via P. Gobetti 85, 40129 Bologna, Italy.
² BeC s.r.l., R&D Division, Via C. Monteverdi 49, 47122 Forlì, Italy.
³ University of Bologna, Department of Chemistry "G. Ciamician", Via P. Gobetti 85, 40129 Bologna, Italy; Tecnopolo di Rimini, Via Dario Campana 71, 47922 Rimini, Italy. Electronic address: luca.valgimigli@unibo.it.

PMID: 38713979
DOI: 10.1016/j.foodchem.2024.139289

Abstract

To verfy their difference from isolated fatty acids, the absolute kinetics of peroxidation was studied for seven triglyceride-based oils of olive (OLI-1, OLI-2), high-oleic sunflower (SUN-HO), high-oleic and high-linoleic safflower (SAF-HO, SAF-HL) grapeseed (GRA) and borage (BOR), by oxygen uptake monitoring, using 2,6-di-tert-butyl-4-methoxyphenol and 2,2,5,7,8-pentamethyl-6-chromanol as reference inhibitors. Propagation constants (k_p/M^-1 s^-1 at 303 K in PhCl) were respectively 34.8 ± 2.3, 35.1 ± 1.8, 40.6 ± 5.5, 36.0 ± 7.7, 160.8 ± 5.1, 145.1 ± 24.5, 275.1 ± 63.8, while oxidizability responded to empirical equation k_p(2k_t)^-½/M^-½s^-½ = 1.63 × 10^-3[allyl >CH₂/M] + 1.82 × 10^-2[bisallyl >CH₂/M], based on fatty acids residues assessed by GC-MS. Peroxidation kinetics was markedly different from that of isolated fatty acids. The H-bond basicity of all oils was measured by FT-IR affording Abraham's β^H₂ values in the range 0.55 ± 0.03. H-bonding explained the protection of oils measured for seven reference phenolic antioxidants, except for the catechols quercetin and caffeic acid phenethyl ester, which were 2-to-4-folds more effective than expected, supporting a proposed different mechanism.

Keywords: Borage; Grapeseed; Hydrogen bond; Olive; Oxygen; Peroxyl radicals; Safflower; Sunflower.