Lipophilic rutin derivatives for antioxidant protection of oil-based foods

The lipase-catalysed synthesis of lipophilic flavonoid antioxidants via rutin acylation with fatty acids (C4-C18) in 2-methylbutan-2-ol was investigated. Conversion yields of rutin fatty acid esters varied from 27% to 62%, depending on fatty acid chain length. Radical-scavenging capacity of compounds synthesized was evaluated against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, inhibition of lipid peroxidation was examined in beta-carotene linoleate system and their potential to act as food antioxidants was studied in sunflower oil using Rancimat test. The results suggest that lipophilic rutin esters, prepared via enzymatic esterification of rutin and fatty acids, may be useful agents in protection of oil-based foods against oxidation. Induction times of esters in the Rancimat test increased with their hydrophobicity. Esters of rutin with stearate, palmitate, oleate, linoleate and linolenate were found to be the most efficient agents of all compounds tested. (C) 2010 Elsevier Ltd. All rights reserved.