Lipid Protein Interactions in Offal Protein Isolates: Effect of Several Solvents on Lipid Extraction

The effect of solvents of increasing polarity on lipid extraction of bovine lung and rumen proteins, isolated by two different procedures, namely, alkaline solubilization of the protein followed by its isoelectric precipitation, and sodium dodecyl sulfate solubilization of the protein and its subsequent precipitation by ferric chloride was studied. A hyperbolic relationship was observed between the amount of lipid extracted and the dielectric constant of the solvent used. This relationship was described by an equation which allowed the calculation of the total amount of lipids present in the isolates and the average intensity of the interaction between lipids and proteins in each system. Relative composition of fatty acids in lung isolates showed marked dependence on the polarity of the solvent employed.