I have done an experiment to try to prove or disprove this, since, like you I had often heard it.

In my trials the pit didn’t help at all, but rubbing the surface of the avocado with a cut lemon really seemed to do the trick.

@pdworkin is right; the pit does nothing to stop browning. When you cut, smash or otherwise damage the cells of an avocado, an enzyme is released that, in the presence of oxygen, forms a brown pigment. You can’t do anything about the release of the enzyme, but you can remove the oxygen from the equation by using plastic wrap directly in contact with the exposed avocado flesh. If you combine this with the lemon juice trick, that’s about the best you can do.

It’s always a comfort when @Harp shows up.

Yes, lemon juice does it. Or why not balsam vinegar.

@oratio I don’t think that being acidic is what does the trick. The citric acid in the lemon juice is effective because it’s a powerful antioxidant. I like the idea of using balsamic vinegar, but I don’t find evidence that acetic acid has the same degree of antioxidant activity. It would be an interesting experiment , though.

I’ve circumvented this problem by ensuring that once an avocado is cut open, it is entirely consumed. It is by far, my favorite food (love BLT+A and a thousand other ways). My parents owned several orchards for many years and I have never, ever tired of eating avocados. Sherry and I have one very large fruit bearing tree just loaded right now and she has quite a few young ones growing nicely. See ya….Gary/wtf

The real secret is to use the whole avocado when you cut it!

As they say in oz, ” ‘ave an avo!”

Awwwwwww shoot, @whatthefluther beat me to it, you’re pdq wtf!”

If you are dealing with Guacamole, put a wet paper towel on it, and refridgerate, and it will last much longer.

@Harp Interesting. I always thought it was being acidic that did it.