verb

change or cause to change to a different, less attractive colour.

do not over-knead the dough or it will discolour

stain,mark,soil,dirty,make dirty,streak,smear,spot,tarnish,sully,spoil,mar,disfigure,blemish,blacken,char,fade,bleach,wash out,rust,weather,stained,marked,spotted,soiled,tarnished,blackened,bleached,faded,yellowed,rusted,rusty,oxidized,weathered