Catching Cashmere Fakes

The soft hair under a goat’s neck is the key source of expensive cashmere fibers. Yak and sheep manes, which are much less valuable, are sometimes blended or exchanged with cashmere. To verify fabric labels, textile manufacturers usually rely on fiber surface analyses done with light microscopy or scanning electron microscopy. But those methods can be time-consuming and subjective. Now, a team in Italy has developed a proteomics strategy to identify the species from which a fiber originates and to quantify its presence in mixtures (J. Mass Spectrom. 2013, DOI: 10.1002/jms.3222). Researchers led by the University of Parma’s Stefano Sforza analyzed keratin found in fiber samples and identified a dozen species-specific sequences. They checked the authentication technique in blind tests on a variety of animal fibers from Afghanistan, Australia, China, Iran, Mongolia, and South Africa. One of the researchers, Claudia Vineis of the Institute for Macromolecular Studies, in Biella, Italy, had previously developed anti­bodies to distinguish cashmere from wool fibers. But unlike the new method, the antibody technique and other chemical strategies for authenticating fiber don’t produce consistent results when the fiber is dyed, bleached, or otherwise depigmented.