Stabilization of soybean oil with heated quercetin and 5-caffeoylquinic acid in the presence of ferric ion.
The effect of heated quercetin (400 mg/kg of oil) or 5-caffeoylquinic acid (5-CQA) and the presence of ferric ion (2.2 mg/kg of oil) on the stability of soya oil oxidized in an oxidative stability index (OSI) instrument was investigated. After heating the phenolic at 100 degrees C or 150 degrees C, the OSI values of treated oils were not significantly (p < 0.001) different, whereas, at 200 degrees C, the values decreased significantly with addition of quercetin, but not with 5-CQA. However, the antioxidative activity of quercetin remained significantly greater than that of 5-CQA. The antioxidative potency of quercetin was reduced significantly by addition of ferric palmitate (FP), but that of 5-CQA was not. Reaction between the ortho-dihydroxy groups of the quercetin and ferric ion may reduce the number of hydroxyls available to react with free radicals. Chelating action of 5-CQA might be provided by ortho-dihydroxy grouping of the quinic acid moiety.
Bastos De Maria
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Instituto Biomédico, UNI-RIO, Rua General Sampaio 71 apt. 911 bloco 2 Caju CEP 20931-350, Rio de Janeiro, Brazil. cabm@acd.ufjr.br
Moreira Santos
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José De Lima Dias
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Marana
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D002726:Chlorogenic Acid / Q000737:chemistry*; D005290:Ferric Compounds / Q000737:chemistry*; D006358:Hot Temperature; D007477:Ions; D010084:Oxidation-Reduction; D011794:Quercetin / Q000737:chemistry*; D013024:Soybean Oil / Q000737:chemistry*
D005290:Ferric Compounds; D007477:Ions; D002726:Chlorogenic Acid; D013024:Soybean Oil; D011794:Quercetin