Avocados are becoming a staple in the meals of health aficionados. That’s hardly a wonder given this green-skinned fruit with creamy texture and mild flavor is loaded with nutrients like vitamins, monounsaturated fats, and fiber. The versatile avocado fits right into a guacamole, a milkshake, or a salad. You may even have it raw with a sprinkling of salt or paprika.
The standard serving size of the fruit is one half a day. But you might have noticed how the fruit turns brown very quickly when kept in the open.
[pullquote]It’s safe to eat a slightly browned avocado if it isn’t too bitter for your taste. It’s better to scoop off the brown part and eat the rest. But don’t eat the cut fruit if it has been lying in the open for a long time; there’s a risk of bacterial and fungal contamination.[/pullquote]
This is due to the presence of an enzyme called polyphenol oxidase (PPO) in it. PPO helps in the rapid oxidation of the avocado phenols (which give avocado much of its nutritional value) into quinones. These smaller molecules of quinone join to form a long chain of polymers called polyphenols. This polymerization manifests itself in the browning of the avocado flesh. The trick to keeping the fruit fresh is delaying this reaction.1
[pullquote]Not just avocado, any fruit or vegetables containing phenols, such as apples or potatoes, turn brown when exposed to air.[/pullquote]
So how do you store the other half and keep it from getting brown and slimy? Here are a few tips on how to keep cut avocado fresh for days together.
1. Store The Cut Avocado With Chopped Onions
[pullquote]This method will preserve the fruit for up to 5 days.[/pullquote]
While this might sound strange to you, refrigerating the cut avocado with chopped onions is by far the most effective technique of maintaining the freshness of the fruit. When cut, onion gives off sulphur dioxide, which is an effective inhibitor of polyphenol oxidase and is widely used to control enzyme-caused browning.2
2. Deep Freeze The Cut Avocado At 5 ºC
[pullquote]This will give the avocado a shelf life of 5 days.[/pullquote]
Yet another method is to store the fresh-cut avocado at 5 ºC. A study showed that when stored at this temperature, the softening and the darkening of the pulp was lower. This is because low temperature slows down enzyme activity, and 5 ºC is low enough to slow down polyphenol oxidase.3
3. Dab The Cut Avocado With Lime Or Lemon Juice
[pullquote]If you apply lime or lemon juice and refrigerate it, the avocado will stay fresh for at least 2 days.[/pullquote]
Sprinkling or dabbing lime or lemon juice on the exposed area of the fruit ensures freshness for a relatively longer period. A study showed that 90–100% PPO inhibition was obtained when apple cubes were dipped in a mixture of ascorbic acid (vitamin C) and citric acid.4 Limes and lemons, being rich in both these acids, could help protect the avocado surface from browning by inhibiting the activity of polyphenol oxidase.
4. Plastic-Wrap The Cut Avocado Or Store In An Airtight Box
[pullquote]Storing the avocado in an airtight container will keep it fresh for a day.[/pullquote]
Like we discussed, the chemicals in the avocado pulp react with oxygen, which gives it the brown color. If you minimize its contact with air, you could reduce the oxidization of the fruit. To do this, tightly cover the unused portion with a plastic wrap, making sure to keep out any air bubbles, and refrigerate. Or you could keep the fruit in an airtight container for a similar effect.
So now that you know the methods of preserving your fruit, bid adieu to wastage or forced overeating, because even good things, in excess, can be harmful.
References
