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ARS Home » Plains Area » Manhattan, Kansas » Center for Grain and Animal Health Research » Grain Quality and Structure Research » Research » Publications at this Location » Publication #140092

Title: LIPID EXTRACTION FROM WHEAT FLOUR USING SUPERCRITICAL FLUID EXTRACTION

Author
item HUBBARD, JOHN
item DOWNING, JOHN
item Ram, M
item Chung, Okkyung

Submitted to: Cereal Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/11/2004
Publication Date: 11/1/2004
Citation: Hubbard, J.D., Downing, J.D., Ram, M.S., Chung, O.K. 2004. Lipid extraction from wheat flour using supercritical fluid extraction. Cereal Chemistry. Vol. 81(6):693-698.

Interpretive Summary: Wheat flour contains a small quantity of fats that have important roles in human nutrition and also in making better-quality baked products. Fat content is not equal to all wheat varieties and classes. The difference in fat content is one of factors to differentiate flour quality. Fat is separated from flour, using an organic solvent, which is usually toxic and cost us to dispose of. Due to environmental concerns, the cost of disposal of hazardous solvent waste, and the time required for extraction, we looked for a method to extract fats from flour that would be faster, less costly, and more environmentally friendly. Carbon dioxide is normally a gas but it becomes liquid-like when the pressure and temperature become high. There is an instrument, called supercritical fluid extraction (SFE) system, for extracting fats from soybeans. We studied to develop a SFE system to extract fats from flour with liquid-like carbon dioxide, using SFE system, that produces similar results to those obtained by the official solvent extraction method. This new method reduces the fat analysis cost by 15 times (33 cents vs $4.80) with a 14 to 1 reduction of solvent cost, a 20 to 1 reduction for solvent disposal cost and nearly 6-fold reduction in analysis time.

Technical Abstract: Environmental concerns, the disposal cost of hazardous waste, and the time required for extraction encouraged us to look for a method to extract lipids from wheat flour that would be faster, less costly, and more environmentally acceptable. Supercritical Fluid Extraction (SFE) with carbon dioxide (CO2) plus ethanol as a modifier has provided that medium. The method is fully automatic. Extraction of non-starch free lipids (FL) or crude fats from wheat flour (about 5 g) by SFE using CO2 plus 11.7 mole % ethanol (12.2% by volume) as modifier, at 7,500 psi (51.7 Mpa) and 80oC, was compared to the AACC Approved Method of Soxhlet extraction using petroleum ether. The precision of the FL extraction by SFE was comparable to that of Soxhlet with a 14.6 to 1 reduction in the overall analysis cost ($0.33 vs $4.80 per sample), including a 14 to 1 reduction in the cost of organic solvent and a 20 to 1 reduction for solvent disposal cost, and a possible 6-fold reduction in analysis time.