12—THE YELLOWING OF WOOL: A SURVEY OF THE LITERATURE

Abstract

The causes of yellowing of wool are discussed and classified, and the literature on yellowing is reviewed mainly in relation to two types of yellow discoloration that cause concern commercially: one that is present in the scoured wool and shows a marked tendency to fade on exposure to light, and one that arises when wool is wet-processed at elevated temperatures. The yellowing of wool by irradiation and by heating, and the effect of the heating of peptides and amino acids, are discussed, and it is shown that suint is a source of yellow pigment. Protection against, and inhibition of, yellowing are also considered.