Melanin production in high yield, from chopped garden turnips by extracting with aqueous ammonia, acidifying extract with hydrochloric acid and washing precipitate

摘要

Preparation of melanin (I) involves (a) treating chopped garden turnips with aqueous ammonia at 60-80[deg] C, pH 8-11.8 and aqueous ammonia to plant residues ratio 1:4.8-11.8, (b) after 1 hour adding hydrochloric acid to adjust pH to 3-3.9, (c) after 4-5 hours washing the precipitate with acetic acid of pH 4-5, acetone and alcohol and (d) filtering off the precipitate, vacuum drying and packaging.