Physicochemical Properties of Melanin from A. auricula Fruiting Bodies

The physicochemical properties of melanin from Auricularia auricula fruiting bodies were studied. The result showed that A. auricula fruiting bodies melanin powder was dark with a little red and yellow colored (L* = 41.03, a* = 2.26, b* = 3.78). A. auricula fruiting bodies melanin was insoluble in both water and common organic solvents. It dissolved only in alkali aqueous solution and precipitated acidic aqueous solution (pH<3). A. auricula fruiting bodies melanin was gradually oxidative bleached by oxidant and was stable to reducer. It exhibited strong optical absorbance in a wide UV-VIS spectral range. Furthermore, these physicochemical properties were very similar to those of the melanin reported in the previous studies and to those of synthetic melanin. A. auricula fruiting bodies melanin could potentially be used in the food industry as a natural colorant.