Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 15, 2005
Publication Date: May 1, 2005
Citation: Kuk, M.S., Tetlow, R., Dowd, M.K. 2005. Cottonseed extraction with mixtures of acetone and hexane. Journal of the American Oil Chemists' Society. 82(8):609-612. Interpretive Summary: Cottonseed meal and oil are produced from cottonseed by solvent extraction. Although cottonseed meal is valuable as animal feed, the use of cottonseed meal is limited by the toxicity of gossypol. Commercial hexane, currently used for extracting oil from cottonseed, does not efficiently extract gossypol. Hence, the cottonseed meal produced by extraction with commercial hexane has a small amount of gossypol. In comparison, pure acetone is known to efficiently extract oil and gossypol from cottonseed. Although the cottonseed meal produced by pure acetone contains a negligible amount of gossypol, the meal has a detrimental odor, known as "catty odor." SRRC scientists found that adding small amounts of acetone (up to 25%) to hexane significantly increased extraction of gossypol from cottonseed flakes. The SRRC scientists also found that a mixture of acetone/hexane with 10% acetone can be used to efficiently extract oil and gossypol from cottonseed, and produce cottonseed meal without "catty odor." The research directly benefits the U.S. farmers who grow cotton, and indirectly the oilseed processing industry which are involved in producing cottonseed meal and edible oil.
Technical Abstract: Cottonseed flakes were extracted with mixtures of n-hexane and acetone with the concentration of acetone varying between 10 and 75%. Adding small amounts of acetone (<25%) to n-hexane has significantly increased the extraction of free and total gossypol from cottonseed flakes. Sensory testing detected no difference in the odor of cottonseed meals of those produced either by extraction with 100% n-hexane or by extraction with a 10/90(v/v)% of acetone/hexane. More than 80% the free gossypol was removed by the 10/90% acetone/hexane extraction mixture. A solvent mixture containing 25% acetone removed nearly 90% of the free gossypol that was removed by extraction with pure acetone and had only a minimum increase in meal odor. In contrast, cottonseed meals produced by extraction with pure acetone had a much higher odor intensity. The composition of the cottonseed crude oil was insignificantly affected by the acetone concentration of the extraction solvent.