Chain-breaking antioxidants differ in their effectiveness at inhibiting lipid oxidation because of their chemical properties and physical location within a food. Our objective was how the physicochemical properties of four structurally related lipid-soluble antioxidants were related to their antioxidant activity. Antioxidants differed in the number of methyl (α-tocopherol and δ-tocopherol) or hydroxyl (butylated hydroxytoluene (BHT) and 4-hydroxymethyl-2,6-ditertiarybutylphenol) groups. Surface activity of the antioxidants was in the order of δ-tocopherol > α-tocopherol ≈ 4-hydroxymethyl-2,6-ditertiarybutylphenol > BHT. Free-radical scavenging activity was similar between α-tocopherol and δ-tocopherol as well as BHT and 4-hydroxymethyl-2,6-ditertiarybutylphenol. In bulk menhaden oil, BHT was a more effective antioxidant than 4-hydroxymethyl-2,6-ditertiarybutylphenol while α-tocopherol was more effective than δ-tocopherol. In menhaden oil-in-water emulsions, BHT was a more effective antioxidant than 4-hydroxymethyl-2,6-ditertiarybutylphenol while δ-tocopherol was more effective than α-tocopherol. These results indicate that the surface activity and polarity of lipid-soluble antioxidants were not the only determinants of their antioxidant effectiveness in food lipids.
- Lipid oxidation; fish oil; interfacial tension; antioxidants; tocopherol; BHT; ω-3 fatty acids
Available at: http://works.bepress.com/djulian_mcclements/143/