Biological Systems Engineering


Date of this Version



Published in Transactions of the ASAE Vol. 48(5): 1883−1888. Copyright 2005 American Society of Agricultural Engineers. Used by permission.


Soxhlet and recirculated solvent extraction methods were used to extract lipid materials from grain sorghum DDG. The lipid content in DDG with a moisture content of 6.7% (dry basis) was as high as 9.32% of the dried DDG as determined by Soxhlet extraction with n-hexane. There was a slight increase in the lipid yield from 9.21% to 9.68% when the moisture contents increased from 2.1% to 17.4% (d.b.). Thin-layer chromatography (TLC) analysis showed that the sorghum lipids were composed of triacylglycerols, fatty acids, fatty alcohols, fatty aldehydes, free sterols, wax esters, and steryl esters. A bench-scale recirculated extraction system was used to investigate the extractability of lipid materials from the DDG under various experimental conditions including solvent to solid ratio (2:1 to 5:1), extraction temperature (45°C, 55°C, 68°C), and extraction time (1 to 6 h). The extractability of DDG lipid ranged from 70.3% to 94.5%. At extraction temperatures near the boiling point of n-hexane, a solvent to solid ratio of 3:1, and an extraction time of 4 h achieved the maximum lipid yield. There was no apparent increase in the extraction yield with further increase of the solvent to solid ratio or extraction time.