If you are a faithful consumer of fruits and vegetables, you will have noticed how some of them become dark at the slightest blink. A very common example is apples, but it also happens with other foods of plant origin such as avocado, and even with foods of animal origin and fungi such as mushrooms.
What is the reason behind this sudden darkening? Can we not prevent our avocados from turning blacker than coal? Calm. The truth is that there are some homemade tricks that allow us to keep avocado degradation at bay.
Blame it on enzymatic browning
First of all, we must know that the process behind the color change of many vegetables is known as enzymatic browning. “Browning” comes from the darkening or color change caused in the food, and “enzymatic” from the word “enzyme”. an enzyme not is a misspelled adverb of placebut a protein that fulfills a specific function in the human body.
Specifically, the enzymes involved in the enzymatic browning reactions that affect avocados and other fruits are called polyphenoloxidases or tyrosinases. These molecules intervene in the oxidation reactions that take place on the cut surface of the food, altering its color and causing a loss of organoleptic quality. Nobody likes poached fruit, right?
In itself this color change does not have to imply a danger towards health, but it does weaken the integrity of the fruit. That is to say: it makes it more susceptible to degradation and the growth of altering and even pathogenic microorganisms, as well as moulds. For this reason, enzymatic browning is a phenomenon that is fought against in the food industry. To inhibit its appearance, factors such as temperature, pH or oxygen are played with. But what can we do at home as consumers?
Why does avocado go bad so quickly?
Once the theory is known, it turns out that the practice is quite different. An avocado does not always darken in the same way, but before each opening we can find a whole world of possibilities and surprises. Sometimes we find that certain areas have already darkened when the avocado is cut, probably due to excessive ripening of the interior of the fruit or problems during transport related to temperature.
The ripening point of the avocado also affects its subsequent oxidation: if the avocado is more ripe, then it means that its shelf life is shorter. There may also be weight loss in avocado associated with a higher concentration of its fats. All this happens because the avocado is a climacteric fruit. That is, it continues to breathe after its collection. And it does so by ethylene production: a plant hormone fully involved in changes in the fruit after harvest.
This is the reason why we must not store avocados along with other non-climacteric fruits such as orangestangerines, cherriesraspberries, blackberries, lemons, strawberries, pineapples or grapes. These last fruits slow down their maturation after tearing them from the tree, while the aforementioned climacteric fruits —which also include the banana, the pear or the apple—they don’t and continue to ripen.
Tricks to prevent avocado from turning black
As we have seen, the very nature of the avocado makes it a very sensitive fruit to agents such as temperature or humidity, as well as to conservation in general. Both towards his own kind and to other fruits. However, we must not give up. There is still hope. It is possible to prolong the useful life of our greenish friend so that its consumption don’t be “doomed” to failure. These are some tricks that we can use so that the avocado does not spoil before its time:
- After cutting it in half, add a squeeze of lemon to the remaining half avocado that you want to keep. The other half, by overwhelming logic, must be consumed. If not, why the hell did you split an avocado? Lemon acid lowers the pH, inhibiting the activity of the polyphenol oxidase enzyme responsible for oxidation and therefore takes longer to darken.
- The use of heat does not seem very viable in fresh avocado, except for some specific recipes. So this advice is totally fake and useless for avocado: although not for other fruits. You should know that heat inactivates the enzyme polyphenol oxidase: is the method used in the food industry to make preserves, for example, by immersing the fruits in very hot water above 100ºC. You already know something new. Knowledge never gets in the way, right?
- At the other extreme we find the cold. Of course, the very conservation of the avocado in the fridge helps slow down the activity of the enzyme polyphenoloxidase. So don’t forget to store your half avocado cold. Also for food safety, since this reduces the proliferation of possible pathogenic microorganisms.
- Finally, the final trick. It is the most effective to preserve the avocado in optimal conditions, and consists of introducing one of its halves into a container with water. In this way, the surface of the avocado will not be in contact with the oxygen in the air and you will avoid deterioration. From my own experience, it is one of the best techniques you can use to extend the shelf life of your avocado. Note that the texture becomes softer: ideal for spreading, but less interesting in other preparations. yes, as much lasts 2-3 days in the fridge. Although the appearance is good, it is possible for pathogenic microorganisms to grow without us noticing. don’t freak out and don’t even think about leaving it for weeks in the fridge as some viral videos of tik tok. If you do, you’ll be risking food poisoning.
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