Isolation and characterization of natural melanin derived from silky fowl (Gallus gallus domesticus Brisson)

Water-insoluble melanins derived from silky fowl (SF-melanin) were isolated using an enzymatic extraction procedure. The yields of the pigments from periosteum, ovary or testis, trachea, skin and muscle, were 21.3, 13.7, 10.2, 1.1, and 1.0 mg/g, respectively, on a fresh tissue basis. The isolated pigments were identified as melanins according to the Electron Paramagnetic Resonance Spectroscopy spectra. Using synthetic melanin as a calibration, their physicochemical and morphological properties were further characterized by X-ray photoelectron spectroscopy (XPS) and advanced imaging technology. Elemental composition analysis by XPS revealed that the main component of the SF-melanin was eumelanin. The morphological study showed that (1) the SF-melanin displayed ellipsoidal melanosomes which was regarded as representative of the natural material; and (2) the SF-melanin maintained its natural integrity. In conclusion, our enzymatic extraction method yielded highly purified products while maintaining the natural properties of the SF-melanin, which could be chemically, physically, morphologically, defined as eumelanin.