Why does sliced potato or apple become dark if kept in open air for sometime?
Two substances known as tyrosine and tannin which are present in potato and apple are responsible for this. Oxygen in the air oxidizes t...
http://getallsolved.blogspot.com/2014/03/why-does-sliced-potato-or-apple-become.html
Two substances known as tyrosine and tannin which
are present in potato and apple are
responsible for this. Oxygen in the air oxidizes tannin within 10-15 minutes transforming it into polyphynol, which is dark brown in colour. Simultaneously oxygen
transforms tyrosine into a
black-coloured pigment named melanin.
FYI:
There is abundant melanin in the skin of Negro people so they are black. Lesser
the amount of melanin in the skin whiter is the complexion. Skin of European have very little
melanin.
