melanize
/məˈlænaɪz/Definitions
1. verb
to give a dark brown or black color to something, especially by the action of melanin, or to become or cause something to become dark brown or black
“The plant began to melanize as it ripened.”
2. noun
the process of becoming dark brown or black, especially due to the action of melanin
“The melanization of the fruit was a sign of its ripeness.”