46C-2 |
Soybean oil body stability and oleosin solubility |
L. WANG1, D. K. Allen2, and B. Y. Tao2. (1) Dept. of Food Science, Purdue University, 1160 Food Science Building, West Lafayette, IN 47907, (2) Agricultural & Biological Engineering Department, Purdue University, 1146 Agricultural and Biological Engineering Building, West Lafayette, IN 47907 Vegetable oils are stored in spherical organelles called oil bodies. These oil bodies and associated proteins have recently gained great attention, due to potential applications in foods, cosmetics, and pharmaceuticals. Oil bodies are extremely stable during oil seed storage, because their surface is completely covered by a layer of hydrophobic proteins, termed oleosins. This paper discusses the role of oleosins in stabilizing oil bodies. Our objective was to characterize soybean oil body stability and oleosin solubility under different pH and temperature conditions, and in presence of various types of salts, surfactants and organic solvents. Oil bodies were isolated from mature soybean seeds by floatation centrifugation. Oleosins were then purified from oil body preparations by solvent extraction. Stability of the oil body suspension was monitored by measuring the optical density at 600 nm. Integrity of the oil bodies was examined by hexane extraction and analysis of oil content by TLC. Oleosin solubilization was analyzed by BCA method and ELISA. Oleosins are insoluble in water and have very limited dissolution in most of conditions tested with the exception of SDS and GD-HCl. Our results show that low concentrations (0.1% to 5%) of GD-HCl promote oil body aggregation without jeopardizing integrity. At higher concentrations, GD-HCl ruptures the oil body membrane by solubilizing oleosins into the aqueous solution. New methods of oil body purification and oleosin extraction are proposed based on these results. A thermodynamic model will also be presented to correlate salt concentration with oil body stability and oleosin solubility. Oil body stability is critical for the applications in cosmetics and pharmaceuticals. Additionally, in vegetable oil processing, destabilizing oil bodies will lead to higher efficiencies in oil extraction, and thus benefit the industry.
Session 46C, Food Chemistry: Lipids, antioxidants and emulsifiers
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