By, Alexandra Tringali
Avocados are quickly becoming a staple ingredient in American households. They’re loaded with vitamins and nutrients, and their creamy, yet mild flavor allows them to be the perfect addition to almost any recipe, whether it’s brownies, shakes, on toast, or even on their own, with a sprinkle of salt and pepper. However, as soon as you cut into an avocado, the vibrant fruit will begin to brown.
Why does this happen to fruits like apples and avocados? It’s because of the reaction between the phenols and oxygen, from an enzyme called polyphenol oxidase (PPO.) Once the phenols are hit with oxygen, PPO oxidizes them, forming long chains of polymers called polyphenols. These turn any fruit with phenols brown. While the brown flesh is still edible, it may have a bitter taste to it, and the longer the fruit is exposed to air, the more bacteria can grow on it.
However, with the right tips and tricks, you can delay this process and extend your avocado’s shelf life.
The first and most effective method of maintaining an avocado’s freshness and vibrancy is to store it with chopped onions. While this means you probably shouldn’t add this avocado to brownie or milkshake recipes, chopped onions help extend your avocado’s shelf life due to sulfur dioxide. (Try adding both the avocado and onions to scrambled eggs instead!) When cut, an onion releases sulfur dioxide, which inhibits polyphenol oxidase and stops the fruit from browning. Storing an avocado with chopped onions extends it refrigerator life for up to five days.
The lower the temperature an avocado is stored in, the better. Storing an avocado at 5o Celsius (around 41o Fahrenheit) extends the shelf life of an avocado to five days. This is because colder temperatures slow down the polyphenol oxidase activity.
Every elementary school science class included an experiment with putting lemon juice on apples to see if the apples will turn brown. This is because acidic juices, like that from lemons or limes, inhibit polyphenol oxidase. Lemons and limes are rich in ascorbic acid (vitamin C) and citric acid, which keep avocados fresh and green for up to two days.
Basic Storage Technqieues
Tricks like storing an avocado with onions or lemon juice can limit the amount of uses an avocado has, because it can very easily take on the powerful flavors it’s stored with. By tightly wrapping an avocado in plastic wrap or storing it in an airtight container and placing it in the refrigerator, you can avoid browning for up to a day.