Abstract:

The orthogonal array design method was used to optimize the extraction of Auricularia auricula melanin and
the characterization of the melanin was conducted. Through single factor and orthogonal array experiments, the optimum
extraction conditions were obtained as follows: ultrasonic power, 160 W; sample mass 5 g; material-to-liquid ratio,
1:30 (g/mL); sodium carbonate concentration, 2.00 mol/L; and extraction duration, 50 min. The crude extract yield under
these conditions was 9.078 g/100 g. Chemical characterization proved that the melanin possessed strong stability to heat and
low concentrations of oxidant and reducing agent but was sensitive to light. The melanin displayed maximum absorption
peak at 210 nm. Infrared spectroscopy indicated that Auricularia auricula melanin was composed of hydroxy, amino, C=O,
C=C, CH, CH2 and aromatic ring groups. The S:N ratio of the melanin was 0.01, indicating that it is eumelanin and has
functions such as hair blackening and anti-aging.

Key words: Auricularia auricular, melanin, extraction, characterization