Comprehensive utilization of edible mushroom waste residue-Extraction, physicochemical properties of melanin and its antioxidant activity.

In order to promote the comprehensive utilization of the waste residue, the extraction process and the physicochemical properties of melanin from waste residue were studied. Furthermore, the chemical antioxidant activity of waste residue melanin and its protective effect on cell oxidative injury induced by HO were investigated. The results indicated that the ultrasonic-assisted extraction process could be used to extract the melanin from waste residue. Melanin had a good solubility in alkali solution and exhibited a certain stability to thermal. There was no significant difference between melanin control group and waste residue melanin on ABTS, DPPH, and hydroxyl radical scavenging activity. Waste residue melanin significantly inhibited the cell death caused by HO, and the cell viability was restored to 98.09 ± 5.97% when the melanin concentration was 1.6 mg/ml. Cell morphology observation confirmed that the melanin ameliorated the morphological changes of cells induced by oxidative stress.