Studies of Antioxidant Properties of Propolis Extracts

The antioxidant activity of propolis,ethanol extract,supercritical CO2 extract,and ethanol extract of CO2 residue of propolis in rapeseed oil and lard were determined with Schall oven method.The results showed that,the propolis extract containing above 0.01% of total flavonoids can significantly prolong the rapeseed oil oxidation induction period and are efficient grease antioxidants.Flavonoids was one of the main components with high antioxidant activity in various propolis extracts.With the ranges of total flavonoids concentration above 0.005%,the overall anti-oxidative activity had a dose-response relationship.When the same adding amount of propolis and its extract) and temperature(60℃) were adopted,the order of the antioxidant activities of the tested antioxidant agents and propolis extracts in rapeseed oil was found as: TBHQ supercritical CO2 extract of propolis ethanol extract of CO2 residue of propolis ≥ ethanol extract of propolis VE glycine propolis BHT.And the order of the antioxidant activities of the tested antioxidant agents and propolis extracts in lard was found as: TBHQ ethanol extract of CO2 residue of propolis ≥ ethanol extract of propolis ≥ BHT glycine propolis supercritical CO2 extract of propolis VE.This study may provide some experimental data for the application of propolis extracts as natural antioxidants in greasy foods.