There are few things more disappointing in the kitchen than reaching for that leftover half of an avocado, only to find it has transformed into a brown, unappetizing mess. The "leave the pit in" method, while common, is a myth. Here is the actual science – and the olive oil trick – that keeps your leftovers green for days.
Why does avocado brown?
Avocado browns when its flesh comes into contact with oxygen. The avocado flesh contains phenols (plant compounds) and the enzyme polyphenol oxidase. Enzymes are proteins that drive chemical reactions. In the case of avocado, as well as many other fruits, polyphenol oxidase changes the chemical structure of the phenols when they are exposed to oxygen. This reaction creates melanin – a brown-black pigment that also exists in the human body. As a result, the green flesh of the avocado turns brown.
How to prevent avocado browning
An avocado that has already browned as a result of exposure to oxygen is not necessarily inedible – usually, it is safe for eating, although its taste may be slightly bitter. The main problem is the less inviting appearance, and sometimes also a texture that is too soft – another side effect of chemical reactions that occur in the presence of oxygen. Since oxygen is the central factor, the key to delaying the browning is creating a barrier between it and the flesh.
Lemon or lime juice
A common method is to wrap the avocado in plastic wrap, but if you are looking for a more eco-friendly solution, you will be happy to know that it is possible to use available ingredients from the kitchen. One of the techniques is to squeeze a little fresh lemon or lime juice on the cut side of the avocado. The acidity of the juice inhibits the activity of the polyphenol oxidase and thereby slows down the browning process.
Video: Gil Kremer, Gilad Distelman
Olive oil
Another possibility is to brush the avocado flesh with olive oil. Thus, a fatty barrier is created between the fruit and the air, which prevents browning.
Airtight container
After covering the avocado flesh with olive oil or lemon juice, it is recommended to place it in an airtight container and put it in the refrigerator. The container provides an additional layer of protection against oxygen, and the low temperature slows down the activity of the enzymes even further. This combination of factors assists in maintaining the characteristic green color of the avocado.
However, it is important to remember that a cut avocado will last in the refrigerator for only three to four days, and therefore it is better to consume it soon.
The pit does not really help
And if you heard that leaving the pit inside the avocado (or in guacamole) helps to prevent browning – we have less good news: it is simply incorrect. The reason is that the pit does not protect the flesh from exposure to oxygen. Therefore, it is better to stick to one of the methods described above to prevent the avocado from browning.
