Add Lemon Juice
Lemon juice makes the oxidation process slow because it has citric acid and helps to preserve the greenish color of avocado.
Wrap it in plastic
Wrap the guacamole with plastic wrap, and try to keep less air between the guacamole and the plastic to avoid exposure to oxygen.
Pit Placement
While storing, leave the avocado pit in the mixture to avoid browning.
Onion Trick
Add small, chopped pieces of onion because the sulfur present in onions works as an antioxidant.
Store tightly
Choose the container as per quantity so that there is less air between the guacamole and the plastic.
Vacuum Sealing
A vacuum sealer helps to remove the air from the container because it creates a packed environment.