Cooktop Cove: After these tips, your avocados will never turn brown again
The process of choosing food to eat is often dependent on aesthetics. Consumers tend to judge quality based on the presentation and overall look of what they're eating. Whether it be a bruise on the outside or a discoloration on the inside, we usually skip the uglies and opt for the prettiest option.
Although we try our hardest to pick the perfect specimen, beauty never lasts. After cutting into fruits such as avocados, apples, bananas, or pears, one may notice that with time, they still turn brown. This is caused by oxidation. 
Oxidation is a natural process that happens after slicing into fruit. When cut, the membranes of a fruit rupture, exposing them to oxygen. The oxygen mixes with the fruit's enzymes, causing a change in the chemical composition. This is what turns the exposed area brown.
Although the fruit is still edible, it becomes less appealing and the taste changes. On top of that, vitamins A and C are affected by the sunlight, and over time the fruit will lose more of its nutrients. Low temperatures, as well as less light, slows the decrease in nutrients but there is no way to fully stop it. 
Taking a look at avocados in particular, everyone can agree that keeping the pit in significantly reduces the speed of oxidation. Other supplementary methods one can try are:
Having large slices of onions in the same container as your avocado is the most effective way to prevent it from turning brown. The sulfuric acid in the onions counteract with the oxygen to slow down oxidation. Using red onions is less harsh and pungent than yellow or white onions. 
Lemon juice
Although it may alter the taste of your avocado, rubbing lemon juice is the second most effective method in lengthening the oxidation process. The citric acid in lemon juice helps to complex the browning enzyme in an avocado, slowing down the browning process. 
Plastic baggie
Putting an avocado in an airtight bag and sucking out the excess air will reduce its exposure to air, slowing the oxidation process. 
Olive oil
The olive oil will create a protective layer on top of the avocado, preventing air from touching the surface. Although this is a relatively effective method, it can cause your avocado to be overly oily.
There are other less noteworthy approaches, but the possibilities are endless. Let us know if you have any methods that work for you.
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