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Oxidative stability of seed oils extracted with supercritical carbon dioxide
- List, G.R., Friedrich, J.P.
- Journal of the American Oil Chemists' Society 1989 v.66 no.1 pp. 98
- seed oils, extraction, oxidation, antioxidants, carbon dioxide, phospholipids, tocopherols, shelf life, food chemistry
- Dry-milled corn germ, soybean and cottonseed flakes were extracted (at 70-90 C and 12,000 psi) with supercritial carbon dioxide (SC-CO2) to yield crude oils. Oxidative stability of the crude oils was determined and compared to similar products obtained by conventional expeller and/or prepress solvent extraction. Under Schall oven storage conditions (60 C), SC-CO2-extracted oils undergo rapid deterioration and fail to show the normal induction period observed with conventional expeller and solvent-extracted crude oils. The levels of tocopherols found in SC-CO2-extracted oils are comparable to those obtained by expeller or solvent extraction while phospholipids present in significant amounts in conventional crude oils are essentially absent from SC-CO2-processed crudes. The addition of phosphatides to SC-CO2-extracted crude oils improves oxidative stability, which suggests that both tocopherols and phospholipids are required to stabilize crude oils against autoxidation. Heating of SC-CO2-extracted crude oils to deodorization temperatures improves oxidative stability. The destruction of fat hydroperoxides under these conditions probably accounts for improved oxidative stability. A combination of heat and the addition of citric acid and phenolic antioxidants resulted in further improvement of oxidative stability.