This food storage tip is a great hack for keeping half an avocado fresh, and green, for about a week – or any cut, chopped, and sliced avocado – using ingredients you already have!
First, let’s talk about why avocados turn brown in the first place.
How Avocados Turn Brown
This healthy fat is Instagram famous for being spread on toast but also perfect in a green smoothie, diced into salads, or the OG recipe…straight up guac.
This fruit (say it with me, “avocado is not a vegetable.”) is essentially a big berry, biologically speaking, and a modern staple. California grows over 90% of all domestic avocados which is about 188 thousand tons of avos every year. It’s more than just for mashing as avocado oil is another popular staple.
And if you love avocados, it is super frustrating to have them brown so quickly after cutting into one. Before I drop the 411 on how to stop that from happening, let’s talk about why they brown.
Avocados brown due to an enzyme called polyphenol oxidase.
When you slice into an avocado, and expose the flesh to oxygen, the enzyme begins to oxidize, turning the flesh from 70s shagtastic green to wood paneling brown. Ain’t nobody got time for that! Scientifically, polyphenol oxidase converts phenolic compounds found in the avo into another compound called quinones. Every time I try to say that word, I say quinoa. #shrugemoji
The quinones polymerize – meaning they bond with smaller particles into a long chain – into polyphenols. Three guesses on the color those show up as? The answer is brown. I hope that was obvious.
Stop Avocados from Turning Brown
There are many methods out there for keeping cut avocado from going to the Dark Side. No surprise. These things aren’t cheap. So of course a myriad of methods have been tried and tested. I will tell you, most don’t work well. I put 12 methods to the test and there was a clear winner. That said, it’s also a pain in the ass compared to the trick I am about to breakdown.
Some of the methods you find on blogs are the water method, olive oil method, lemon juice method, etc. They all kinda suck, so I am not going to even bother.
For its ease and effectiveness, the onion method is the clear winner.
Stored this way, sliced and diced avocado can keep fresh and green for up to five days. Where the methods above involve moisture, which ultimately degrades the avocado, the onion method does not. Sorry, I don’t want to eat old squishy avocado that has been dressed in lemon juice.
To keep your cut up avocado fresh, simply store it in an airtight container along with some chopped up onion. The color does not matter. Red, yellow, white, or whatever. It just has to be an onion.
Yes, an onion
You know how onions make people cry – maybe you are one of them – well, that same chemical reaction keeps cut avocados green. If you like onion, you can simply palace a slice of it over the top of the avocado, put it in an airtight container, and keep it in the fridge. If you don’t like onion, simply having it in the same container helps. The transfer of flavor is minimal to none.
Why Onions Make You Cry
When growing, onions pull sulfur out of the soil and turn into amino acids sulfoxides, which is a sulfur compound that can easily and quickly become a gaseous state. Like me, after too much Del Taco.
When cut open, the onion releases the sulfoxides and previously separated enzymes meet up with it, causing unstable sulfenic acids, which transform into the chemical known as syn-propanethial-S-oxide. Insert the Transformers transforming sound here, or the theme song. Both work.
That final chemical is volatile. Like three-cosmos-in Real Housewives kinda volatile. It easily vaporizes and causes a burning sensation when it billows up from the cutting board towards your face, making contact with your eyes. And eyes, trying to protect themselves from foreign objects, tear up to expel the irritant.
Fresh Avocado for a Week
Those same vapors that turn up the waterworks on people also retards the compounds and enzymes that result in browning. Kinda cool. I do like the yin yang effect here. Nature you a sassy bitch!
What a simple and easy way to fight food waste! You can chop up the onion for future guac (I call it pre-guacing) or use it up in many o’ recipes after enjoying the avocado. How cool is that? No wasted plastic. No gross avocado water you dump out.
Just fresh, firm, and green avocado.