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Recovery of Bioactive Flavonols from Onion Solid Wastes Employing Water/Ethanol-Based Solvent SystemsDepartment of Food Quality & Chemistry of Natural Products, Mediterranean Agronomic Institute of Chania (M. A. I. Ch.), P. O. Box 85, 73100 Chania, Greece
Department of Food Quality & Chemistry of Natural Products, Mediterranean Agronomic Institute of Chania (M. A. I. Ch.), P. O. Box 85, 73100 Chania, Greece, dimitris{at}maich.gr
Department of Food Quality & Chemistry of Natural Products, Mediterranean Agronomic Institute of Chania (M. A. I. Ch.), P. O. Box 85, 73100 Chania, Greece Food processing by-products and wastes represent in many instances major polluting agents, since they bear a significant load of organic bio-molecules and particularly high chemical and biological oxygen demand (COD and BOD) levels. In this regard the development of processes that will aim at reducing the polluting load by removing added-value phytochemicals from agriculture-food wastes becomes imminent. In the present study, a first approach regarding the efficient recovery of bioactive flavonols from onion solid wastes has been attempted. Major flavonols were identified by liquid chromatography-mass spectrometry techniques and recovery was achieved by using environmentally friendly and food-compatible solvent systems, composed of water/ethanol, and acidified with either acetic or citric acid and HCl. Initial screening of various mixtures showed that significantly higher recoveries (P<0.001) can be attained by using 60% ethanol containing 0.1% HCl. The assessment of factors affecting yield, including extraction time and temperature, was accomplished using a series of extractions on the basis of a 3 x 3 factorial design model. The results obtained showed that maximization of yield is dependent upon increasing both extraction time and temperature.
Key Words: onions food wastes flavonols polyphenols quercetin
Food Science and Technology International, Vol. 14, No. 6,
497-502 (2008) |
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