Isolation and Physicochemical Characterization of Melanin from Ova of Rana chensinensis

Melanin was widely used in the food, pharmaceutical, and chemical industries. In this study, melanin was isolated from the ova of Rana chensinensis (OORC) by means of enzymatic hydrolysis assisted with NaOH. Infrared spectrometry, elemental analyzer, and UV-VIS absorption spectroscopy were performed to explore optimal protein extraction methods and physicochemical characterization of extracted OORC melanin. The results showed that OORC melanin was mainly composed of amino, hydroxy, C=C, C=O, CH2, CH, and aromatic ring groups. The S:N ratio in the OORC melanin was 0.05, consisting mostly of eumelanin and a little protein. The optimal protein extraction method was 0.66 mol/ L NaOH, 40 degrees C for 87 min, and the suitable ratio of NaOH solution to raw material was 20.7:1. This research was aimed at providing a reference for the development and utilization of melanin.