The
generally accepted (Nicolaus et al. 1964) chemical criteria
we use to define a fungal pigment as a melanin are as fol-lows: black colour, insolubility in cold or boiling water and
organic solvents, resistance to degradation by hot or cold
concentrated acids, bleaching by oxidizing agents such as
hydrogen peroxide, and solubilization and degradation by
hot alkali solutions. This recalcitrant property of melanins
has long been used to purify them i.e., treatment of the sam-ple with hot solvents and acids to degrade away virtually ev-ery other form of biological structure, with the assumption
that whatever was left was substantially melanin