Abstract
The official AOCS method for the determination of free fatty acid (FFA) in cottonseed requires dehulling the seed, grinding the meats with a 12-blade food processor, and extracting the ground meats in a butt tube with three portions of room-temperature petroleum ether. The extracted oil, after desolventization, is then titrated with NaOH to the end point of phenolphthalein in a mixed solvent of isopropanol and hexane. Our study showed that this procedure tends to underestimate the amount of FFA present in the oil of cottonseed by as much as 11.5%. It was also found that to obtain consistent and accurate FFA content, a desirable particle size is smaller than 10 mesh (preferably <14 mesh), minimum extraction temperature should be no less than 40°C (preferably greater than 50°C), and the extraction time should be longer than 2 h in a Soxhlet extractor.
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References
Oilseeds Crop Yearbook, Economic Research Service, United States Department of Agriculture, Washington, DC, 1997, p.7.
Trading Rules, National Cottonseed Products Association Incorporated, Memphis, 1998, pp. 50–54.
Official Methods and Recommended Practices of the American Oil Chemists’ Society, 4th edn., AOCS Press, Champaign, 1993, pp. Aa 4–38, Aa 6–38, Ce 1–62.
Wan, P.J., D.R. Pakarinen, R.J. Hron, Sr., and E.J. Conkerton, Alternative Hydrocarbon Solvents for Cottonseed Extraction, J. Am. Oil Chem. Soc. 72:653–659 (1995).
Bailey, A.E., Cottonseed and Cottonseed Products, Interscience Publishers, New York, 1948, p. 376.
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Wan, P.J., Pakarinen, D.R. & Wakelyn, P.J. Concerns for the determination of free fatty acid in cottonseed. J Amer Oil Chem Soc 75, 1321–1324 (1998). https://doi.org/10.1007/s11746-998-0178-5
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DOI: https://doi.org/10.1007/s11746-998-0178-5