Cereal Chem 60:371 - 378. | VIEW
Protein-Lipid Complexes in the Gliadin Fraction.
F. Bekes, U. Zawistowska, and W. Bushuk. Copyright 1983 by the American Association of Cereal Chemists, Inc.
Gliadin preparations were obtained from glutens with different lipid contents and compositions so that the speculated association in dough of certain flour lipids with gliadin proteins could be investigated. Lipid content of the glutens (and the gliadins) varied according to the nature of defatting solvent (n-hexane, n- butanol, water-saturated n-butanol). Gliadin preparations were fractionated into five fractions by gel filtration chromatography on Sephadex G-200. Lipid was found on fractions I and III. Fraction I (eluted in void volume) contained mainly polar lipids, and fraction III contained mainly nonpolar lipids. Gliadin preparations from completely defatted flour (or gluten) contained no carbohydrate, whereas carbohydrate and lipid contents of other gliadin preparations were directly related. Protein subunit composition of fraction I, determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis, depended on whether or not lipids were present in the gliadin preparation. Fraction I of the preparation from completely defatted flour (or gluten) contained only high (greater than 100,000) molecular weight subunits, whereas the analogous fraction from undefatted or partially defatted flour contained, in addition, low (less than 40,000) molecular weight subunits. These results indicate that in the gliadin preparations from undefatted flour (or gluten), lipids (likely galactolipids) caused aggregation of low molecular weight subunits with the high molecular weight subunits.