Browning occurs when an avocado is cut or damaged. Enzymes released due to the damage react with oxygen, causing the flesh to turn brown. The process is called enzymatic browning, and avocados that turn brown this way are still safe to eat.
However, browning can also result from spoilage. In this case, you should discard the avocado.
An avocado turns brown after its flesh is exposed to oxygen. This process is called oxidation. Brown avocados due to oxidation are safe to eat but they can have bitter taste.
However, not all avocados with browning are safe to eat. Browning can also occur due to spoilage.
Avocados can become overripe and go bad due to bacterial growth. Brown and black spots can be a sign of spoilage. A spoiled avocado will smell bad and also taste bad. If you notice a strange smell and the avocado looks mushy, it’s best to discard it.
Mold is another common problem in avocados due to the fruit’s high moisture content. You should discard avocados with mold, even if the mold appears to be only on the skin and not inside the flesh.
Avocados most commonly turn brown due to enzymatic browning and overripeness. Cold damage and spoilage are other reasons.
- Enzymatic browning: This occurs when avocado flesh is exposed to oxygen through damage or improper handling after harvest and during storage.
Fruits and vegetables contain enzymes and compounds stored in separate parts of the cells. These molecules are released when the fruit is damaged, cut, or overripe. In the presence of oxygen, the enzymes interact with the compounds (the process is called oxidation). This reaction produces melanin, a pigment that causes browning.
Enzymatic browning also causes nutrient loss and less desirable taste, texture, and appearance.
Other reasons avocados turn brown include:
- Overripeness: Ripening is desirable up to a certain point. As fruit ripens, cells break down, releasing enzymes, compounds, and sugars. This causes browning inside the fruit due to oxidation. It also creates an environment for bacteria and yeast to grow. Even if overripe fruit doesn’t spoil immediately, it is likely to taste worse than properly ripe fruit.
- Cold damage: Cold damage, also called chilling injury, occurs when fruits are stored at low temperatures before ripening. Cold-damaged avocados can have gray-brown or darkened spots or streaks in the flesh. These are safe to eat but will likely have a rancid taste.
- Spoilage: Avocados can go bad due to microbial (bacteria and fungi) growth.
If you have brown avocados:
- First, check the smell and texture: You can eat a brown avocado if the browning is caused by oxidation. In this case, it won’t smell strange. You can either eat the whole thing or scrape off the brown part if you prefer not to eat it. However, if the avocado smells rancid or sour or looks too mushy or slimy, you shouldn’t eat it. Don’t smell a moldy avocado because you could inhale mold spores.
- Use in different recipes: Brown avocados are likely to be softer. Once you’ve determined they are safe to eat, you can use them to make guacamole, avocado dip, or spreads. You can also add them to smoothies or use them in desserts, like a chocolate mousse.
- Store in the fridge or freezer: Brown avocados are likely to spoil quickly. If you don’t plan to consume them right away, you can store them in the fridge with a bit of oil and lemon juice in a sealed container, or freeze them for later use. Still, it’s best to consume them quickly, as they can spoil faster.
You can prevent premature browning by properly choosing, storing, and preparing avocados:
- Examine the avocados before buying. Choose the ripeness based on how soon you plan to eat the avocado. Some varieties stay green as they ripen, while the Hass variety changes color during ripening. This process begins with the skin darkening and eventually turning a deep purple. For the Hass variety, choose avocados with dark purple skin and soft flesh if you plan to eat them right away. If you need them to last longer, go for ones that are firmer to the touch, with skin that appears more green, as they still need time to ripen.
- Store ripe avocados in the fridge. This can make them last longer. If they need more time to ripen, leave them at room temperature. Once ripe, move the avocados to the fridge if you’re not ready to eat them.
- Wash the avocado before cutting. The surface of the fruit can have microbes that will later penetrate the flesh when cutting. So, it’s best to wash and dry the fruit prior to cutting.
- Seal leftover avocado with lemon or lime juice. The acidic nature of lime or lemon juice slows down oxidation by preventing the enzyme from working properly.
- Freeze leftover avocado for later use. Mash the leftover avocado and mix it with lemon juice to keep it fresher. Then, defrost it at room temperature when you want to use it.
Guacamole is a simple, flavorful way to use avocados. It’s made by mashing ripe avocados and mixing them with lemon and lime juice, tomatoes, red onions, jalapeño peppers, cilantro, and spices. A few ways to prevent guacamole from going brown include:
- Limit air exposure: Cover guacamole with a lid or plastic wrap. You can also use airtight containers, such as vacuum-sealed bags.
- Add a layer of oil: When oil covers the surface, it prevents oxygen from reaching the guacamole. You can use olive oil to enhance the flavor.
- Refrigerate quickly: To keep guacamole fresher for longer, refrigerate or freeze it as soon as possible after preparation.
If guacamole smells rancid or sour, has a slimy texture, or has too much water, it’s likely gone bad. It’s better to discard it.
Avocados turn brown after cutting, a process known as enzymatic browning. This type of browning is safe to eat. However, spoilage can also cause the avocado to turn brown. To check if it’s still good, smell it and check the texture. If the avocado smells rancid, feels slimy, or has mold, it’s best to discard it.
