Abstract:

Auricularia auricula melanin was measured for its solubility and UV and infrared spectral characteristics. Meanwhile, optimization of its extraction technology was conducted. The melanin was soluble in alkaline solution, but insoluble in water, acid solution and organic solvents. The UV and infrared spectral characterization indicated that the melanin had a structure identical to that of synthetic tyrosine melanin, and belonged to the group of 3,4-dihydroxy phenylalanine (DOPA) melanins. The one-factor-at-a-time and orthogonal array design methods were used to optimize the ultrasonic-assisted extraction technology of Auricularia auricula melanin, and extraction duration of 80 min, ultrasonic power of 80 W, NaOH concentration of 1.25 mol/L, material-to-liquid ratio of 1:30 were found optimum, and the crude extract yield reached up to 9.107% under these optimum conditions. Ultrasonic-assisted extraction has some advantages over conventional methods, such as simplicity, rapidity, better effectiveness, and so on.

Key words: Auricularia auricula, melanin, identification, extraction technology