Cereal Chem 54:1198 - 1206. | VIEW
Quantitative Studies of Wheat-Flour Lipids Extracted with Various Solvents by an Elution Method.
R. L. Clements. Copyright 1977 by the American Association of Cereal Chemists, Inc.
Untreated, slurried-and-dried, and hexane-Soxhlet-extracted flours and flour fractions mixed with diatomaceous earth were packed in columns and lipids were eluted with various solvents. Among 15 solvents studied, water-saturated 1-butanol (BW) generally give maximum lipid yields, but a 2- propanol:fluorocarbon:water mixture gave comparable results. Hexane elution gave about 20% less and chloroform elution about 20% more lipid than hexane Soxhlet extraction. Most alcohol-containing solvent systems did not give higher yields than 95% ethanol or chloroform alone. Nonpolar solvents generally eluted more lipids from soft wheat than from hard wheat flours, but polar solvents eluted about the same amounts from soft and hard wheat flours. Nonpolar solvents extracted less lipid from flours suspended in water and dried, but as polarities of solvents were increased, yields approached those of untreated flours. Lipids from hexane-extracted flours also increased with solvent polarity. When flours were eluted with a sequence of hexane, chloroform, and BW, a higher proportion of total lipid was extracted by hexane and chloroform from soft than hard wheat flours, but total yields were comparable. Among fractions from nonextracted flour, almost 90% of total ethanol-extractable lipid was in the gluten (7.68% lipid). Gluten from hexane-Soxhlet-extracted flour contained 1.60% lipid and contributed 63.6% of the total. Results suggest that elution of lipids by use of standardized columns and procedures is a practical method for comparative studies of solvents, flours, and flour treatments.