What causes lettuce to brown and go bad when it's cut with a metal knife?

Question

I've noticed if you rip the lettuce it doesn't brown as fast opposed to cutting it with a metal knife, why is that? Does anyone have a clue?

Answer 1

The metal in the knife reacts with the acid in the lettuce and the reaction causes the  veggie to brown faster. It is just a basic chemical reaction.

Answer 2

try uploading the data rays

Answer 3

This maybe a gross way of explaining it but it will make since.  You know when a living like a cow, pig, or even a human is cut or even killed how the air and bacteria eats at it and it starts to decay.  Its the same when you use a metal knife.  It cuts into the lettuce's fibers and over exposes it to air.  Oxidation is what is happening. A plastic or lettuce knife does not have the same effect.  The cut does not disturb the fibers and it lasts longer.