Date of this Version
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.