Preparation of Water Soluble Wool Keratin and Its Application for Human Hair

The study prepared water-soluble wool keratin by modifying disulfide bonds in cystine residues to carboxymethylalanyl disulfide (CMAD) groups using a thioglycolic acid solution under alkaline conditions. The process involved derivatization and oxidation steps, with successful solubilization achieved even without urea and dithiodiglycolic acid. The reaction was optimized at pH 13 for 12 hours to minimize molecular degradation. CMAD wool keratin was tested in permanent waving and bleaching treatments, showing that it effectively prevented damage to the cuticle layers of human hair, even after three repeated treatments, indicating its potential for protecting hair from damage.