Extraction of Lipids From Grain Sorghum DDG

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 determinedby Soxhlet extraction with n-hexane. There was a slight increase in the lipid yield from 9.21% to 9.68% when the moisturecontents increased from 2.1% to 17.4% (d.b.). Thin-layer chromatography (TLC) analysis showed that the sorghum lipids werecomposed of triacylglycerols, fatty acids, fatty alcohols, fatty aldehydes, free sterols, wax esters, and steryl esters. Abench-scale recirculated extraction system was used to investigate the extractability of lipid materials from the DDG undervarious experimental conditions including solvent to solid ratio (2:1 to 5:1), extraction temperature (45C, 55C, 68C), andextraction time (1 to 6 h). The extractability of DDG lipid ranged from 70.3% to 94.5%. At extraction temperatures near theboiling point of n-hexane, a solvent to solid ratio of 3:1, and an extraction time of 4 h achieved the maximum lipid yield. Therewas no apparent increase in the extraction yield with further increase of the solvent to solid ratio or extraction time.