How to Keep an Avocado or Guacamole from Turning Brown
Sometimes you’ll use only half an avocado for your guacamole recipe. If you leave the avocado half in the refrigerator it will begin to brown. The best way to keep it from browning is to use lemon juice. Take a small piece of Tupperware or baggie. Squirt in a bit of lemon juice and set the avocado inside with the skin side up. Seal the bag or Tupperware. It should last a few days this way for you.
Lemon juice also works for guacamole that has begun to brown. Just squirt a teaspoon or so of lemon juice into your guacamole and stir. The brown should magically disappear and return your guacamole to a delicious bright green state.