The proteomics applied to the analysis of luxury animal fibers: a new anti-fraud method

Animal hair fibres like wool, cashmere and yak are obtained from domestic mammals of the genera Ovis, Capra and Bos. Cashmere fibres are valuable natural raw materials used by the fashion industry for manufacturing high quality luxury textiles, and as such are distinct from fibres derived from sheep and yak. Leading companies in the textile sector need objective and precise analytical methodologies able to univocally identify and quantify animal hair fibers present in textile articles, to guarantee that no falsification occurs, especially when cheaper fibers, like wool and yak, are blended with expensive fibers, like cashmere. The traditional and most used methods for identifying animal fibres are Light Microscopy (LM) and Scanning Electron Microscopy (SEM). In Figure 1 are reported SEM images of wool, cashmere and yak fibers. These techniques are subjective depending on the expertise of the operator and often are affected by physical and chemical treatments to which the fibers have been submitted during textile processing. Several methods have been studied to improve the objectivity and accuracy of the results of the animal fiber blend identification, like methods based on the extraction and analysis of DNA [1] or based on specie-specific monoclonal antibodies [2]. Nevertheless, the results obtained are often affected by chemical treatment such as bleaching, dyeing and depigmentation. To remedy these problems, in collaboration with the Department of Food and Drug of the University of Parma, we developed a new method for qualitative and quantitative analysis of animal hair fibers. The method based on electrospray (ESI) mass spectrometry (MS) combined with liquid chromatography (LC) follows a proteomic approach to assess molecular markers for wool, cashmere and yak fibers identification and quantification [1-3]. Keratin from sheep, cashmere goat and yak are similar but not identical, because in some specific parts there are amino acidic variants resulting in specific peptide-markers which can be used to distinguish each animal fiber. These markers have been successfully used not only for qualitative analysis of wool, cashmere and yak blends, but also for quantitative ones.