Effects of Processing on the Bound and Free Fatty Acid Levels in Wool

Bound and free fatty acids in degreased wool fibers were affected to varying degrees by processing treatments. Scouring and dyeing both removed significant amounts of bound and free fatty acids from wool. Free fatty acids were reduced by dissolution into the treatment liquor, whereas bound fatty acids were hydrolyzed under the hot aqueous conditions. Chlorination at pH levels below 3 released over 50% of the bound fatty acids. Chlorine treatments cleave only thioesters but not oxygen esters or amides under these conditions, indicating that a significant proportion of the bound fatty acid is linked to wool by a thio ester bond.