Fiber Matrix
Structural keratin polypeptides form the primary structural matrices that build up animal fibers like wool, cashmere, and mohair. These intermediate filament proteins are arranged in highly ordered parallel bundles within the cortex of the hair. They provide the tensile strength and elasticity required for textile spinning and knitting.
Species Identification
Modern laboratories target these intermediate filament proteins because their amino acid sequences vary slightly between sheep, goats, and camels. Mass spectrometry identifies these tiny differences by looking for specific peptide markers. This method allows the lab to verify if a yarn labeled as pure alpaca contains cheap sheep wool.
Extractability Metric
Extracting these robust proteins from processed textiles requires harsh reducing agents to break the cross-linking disulfide bonds. If the intermediate filament proteins are not fully dissolved, the testing system cannot detect the less abundant fibers in the blend. This chemical extraction process must be executed carefully to avoid destroying the target peptides.
The laboratory must run multiple blank runs to verify that no residual protein carries over to the next sample, as this can lead to false positives when evaluating pure synthetic blends.
Fabric Assessment
Quality control managers at garment factories use protein assays to certify the authenticity of their raw materials. This molecular testing is much more reliable than manual microscopy, which can be fooled by chemically treated sheep wool. Ensuring that the protein signatures match the declared label prevents expensive legal disputes for international apparel brands.
