Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/29/2008
Publication Date: 3/17/2009
Citation: Cleveland, T.E., Carter Wientjes, C.H., De Lucca II, A.J., Boue, S.M. 2009. Effect of soybean volatile compounds on Aspergillus flavus growth and aflatoxin production. Journal of Food Science. 74(2):H83-H87.
Interpretive Summary: Soybeans naturally produce certain volatile compounds that can evaporate into the air. We identified these compounds and tested them for their ability to kill a fungus (Aspergillus flavus) that is harmful to plants and which produces a potent toxin (aflatoxin) that renders food and feed unsafe for human and animal consumption. We learned that two of these volatile compounds inhibit the growth of this fungus and prevents the production of aflatoxin. The results indicate that these two compounds could prove useful in preventing the growth and toxin production on harvested, stored grains.
Technical Abstract: Soybean homogenates produced volatile compounds upon exposure to lipase. These induced volatiles were identified by SPME. Seventeen volatile compounds identified by SPME were chosen for determination of their ability to inhibit Aspergillus flavus growth and aflatoxin B1 (AFB1) production in a solid media assay. These volatiles included aldehydes, alcohols, ketones, and furans. Of the tested compounds, the aldehydes showed the greatest growth and AFB1 production inhibition. These compounds inhibited up to 100% of the observed growth and AFB1 production as compared to the controls. The greatest activity by the aldehydes to disrupt growth was ranked as follows: 2,4 hexadienal > benzaldehyde > 2-octenal > (E)-2-heptenal > octanal > (E)-2-hexenal > nonanal > hexanal. The greatest activity by the aldehydes to reduce AFB1 was ranked as follows: (E)-2-hexenal > 2,4 hexadienal > (E)-2-heptenal > hexanal > nonanal. (E)-2-hexenal and (E)-2-heptenal were tested further in an A. flavus-inoculated corn kernel assay. Both compounds prevented colonization by A. flavus and eliminated AFB1 production when exposed to compound volumes < 10 ul as also shown in the solid media assay. The results suggest that soybeans react to lipase by production of potent antifungal volatiles.