Antioxidative activity of phenolic compounds from white and black berry leaves
2010
El-Shehawy, Sh.M.M. | Goneim, G.A.A. | Ibrahim, F.Y.
Natural antioxidants are in great demand today due to both consumer preference and health concerns as allemative synthetic antioxidants. Therefore, this study was carried out to investigate the extraction, identification of antioxidant compounds from both white and black berry leaves. Phenolic compounds in the extracts were identified and determined by HPLC, then evaluated as natural antioxidants using sunflower oil during 60 days of storage at 63°C. Acid value, peroxide value and TBA value of the stored oil were periodically estimated (each 15 days). The results revealed that total phenolics were 100.54 mg/ml and 31.43 mg/ml (as gallic acid) for methanolic and acetonic extracts of black berry leaves, respectively. Both mentioned extracts exhibited antioxidant activity. Sunflower oil treated with white berry leaves acetone extract (0.20%) had the best peroxide value of 36,06 and also, the percentage of antioxidant effectiveness ranged from 7.05% at zero time to 82.62% at the end of storage period. TBA value of 0.20% black berry leaves methanol extract treated sunflower oil had the highest value (2.512) after 15 days of storage. From an economical and environmental point of view, these fruit byproducts as natural source of antioxidants may act an important role in edible oil industry. Keywords: Phenolic compounds, natural antioxidants, oxidative rancidity and accelerated oxidation.
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