|Hron Sr, Robert|
Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/3/1996
Publication Date: N/A
Interpretive Summary: Cotton is a major crop of the southern United States. Cottonseed, a by-pro an edible vegetable oil and a high protein animal feed meal. Because the meal contains an anti-nutrient chemical called gossypol it is primarily fed to ruminant animals such as cattle, sheep and goats. During processing of cottonseed into oil, gossypol can be deactivated using heat and moisture. However, in some cases, due to various reasons, not enough gossypol is deactivated and an additional processing step is required. A new method is reported, which involves adding a small amount of a chemical called ferrous sulfate to the meal and then exposing the meal to hot alcohol vapor to inactivate gossypol to very low levels. These low levels will allow the meal to be fed to other than ruminant animals possibly increasing its demand and the economic value of this agricultural by-product.
Technical Abstract: Most cottonseed contain gossypol, a polyphenolic anti-nutrient compound. "Free" gossypol is a physiologically active form of gossypol which is toxic to young- and non-ruminant animals. To utilize solvent extracted cottonseed meal as a general feed, gossypol must be either removed or deactivated to a minimum level specified for each individual class of animal. Normally deactivation is obtained prior to oil extraction however the desired level of deactivation is not always obtained. A new supplemental method of deactivation has been found using either ethanol or isopropanol vapor on solvent extracted meal. Using a bench-top setup, ethanol vapor has been found to reduce free gossypol from 0.115% to 0.053% and with the addition of ferrous sulfate a further reduction down to 0.026% has been observed. The supplemental deactivation method can, in most cases, reduce free gossypol to significantly safer feeding levels increasing the utility and possibly demand for cottonseed meal as a genera animal feed protein source.