Page Banner

United States Department of Agriculture

Agricultural Research Service

Title: Gas Chromatographic Characterization of Soapstocks from Vegetable Oil Refining

Author
item DOWD, MICHAEL

Submitted to: Journal of Chromatography
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 8, 1998
Publication Date: N/A

Interpretive Summary: Soapstock is formed as a by-product of the vegetable oil refining process. This low-valued material is a heterogeneous mixture of soap, polar and non-polar glycerides and sterols, and other compounds. Characterization of soapstock has been hampered by the lack of analytical methods capable of distinguishing the many classes of compounds present in the mixture. In this paper, I describe chromatography methods to detect and measure many of the compounds contained within soapstock, and I compare the compositions of soapstocks from corn germ, peanut and cottonseed oil processing. Differences in the chemical composition of the soapstocks can be attributed to oil source and processing differences. The information will be useful to scientists studying alternative uses for agricultural co-products and feed developers producing balanced animal diets.

Technical Abstract: Gas chromatography was used after trimethylsilyl derivatization to determine the composition of soapstocks from corn germ and peanut oil refining. Soap fatty acids, polyalcohols, small carbohydrates, sterols, steryl-glucosides, mono-, di- and triglycerides were measured using a hexamethyldisilazane/pyridine preparation and a high temperature capillary column. Additional peaks associated with the fatty acids appeared in the chromatograms when pyridine was incorporated into the sample preparation. Limiting the concentration of soapstock in the sample or replacing pyridine with a chlorinated solvent reduced the formation of these artifacts.

Last Modified: 9/29/2014
Footer Content Back to Top of Page