Why does lettuce turn pink?
In the same way that an apple browns once cut open, leafy vegetables deteriorate due to oxidation. This is the most common reason for lettuces to turn red or brown, and it happens because of exposure to oxygen.
Pink rib is the pink discoloration of the midrib of lettuce caused by exposure to higher temperatures. If you find that the roots of the lettuce or the edges of the leaves are red, the iron in the lettuce is oxidized, indicating that it is not fresh.
Join Alexa Answers
Help make Alexa smarter and share your knowledge with the worldLEARN MORE