Antioxidant activity of green propolis in model system

Abstract

The lipid oxidation is considered the second cause most important for food deterioration. With the aim to retard or minimized it, the use of antioxidant compounds is necessary. Most antioxidants used today has been originated from synthetic sources, however they have restrictions for use in food because their toxic effects in human health. In consequence in the last decade there was an increase in researches on antioxidants from natural sources, with the aim to identify potentials supplies of these compounds. The aim of this research is to produce hydroalcoholic extracts of green propolis with high antioxidant activity and to evaluate their activity in lipid model systems. The extracts will be produced following the Response Surface Methodology, with the purpose to obtain extracts with maximum antioxidant activity in in vitro essays, using the ORAC (Oxygen-Radical Absorbance Capacity) methodologie. Phenolics compounds in the select extract will be identified and quantified by HPLC/MS. The evaluation of extracts in lipid model system (unsaturated vegetable oil and emulsion) will be performed in accelerated tests: oxidation started by FeCl3, and Oven test followed by spectrophotometric evaluation of hydroperoxides in samples. Volatiles compounds in these samples will be evaluated, using micro extraction in solid phase (SPME) by gas chromatography-mass spectrometry (GS/MS). The antioxidant activity of green propolis extracts will be compared to the effectiveness of synthetics antioxidants permitted by Brazilian legislation as TBHQ, BHA and BHT. Products (oil and/or emulsion) added of propolis extracts which presented the better oxidative stability will be submitted to sensorial analysis in order verify the effect on odour and colour. (AU)