How many times does an avocado darken, why is cold or film not enough to prevent it from oxidizing? Does discoloration mean a health hazard? An expert consulted by Infobae provides all the answers
this avocado : in these times -rich and healthy- is remembered. As it is known: This fruit, which is rich in fiber, lowers blood sugar and reduces the risk of many diseases. Moreover, Also known as avocado avocado in some Latin American countries, It is low in cholesterol and triglycerides and contains vitamins K, C, B5, B6 and E, potassium and folic acid. At the same time It is rich in lutein and zeaxanthin, which are important for eye health.
This fruit, which has so many nutrients and properties, may have only one disadvantage: Once peeled, it does not last long. And the first thing to notice is that when we keep half of it in the fridge, it starts to take on the black color.
Like other fruits such as apples, avocado is oxidized. What is the reason for this sudden darkening? Can’t we keep our avocados from getting darker than charcoal?
The truth is, there are some homemade tricks that allow us to avoid degradation of nature. avocado.
First of all you should know It is known as the process behind the color change of many vegetables. enzymatic browning . “Brown” comes from the darkening or color change that occurs in food, and “enzymatic” comes from the word “enzyme”.
Enzymes involved in enzymatic browning reactions that affect avocados and other fruits are called. polyphenoloxidases or tyrosinases . These molecules interfere with the oxidation reactions that occur on the cutting surface of the food, changing its color and causing organoleptic quality loss.
This color change in itself does not have to imply a danger it is harmful to health, but weakens the integrity of the fruit. For this reason, enzymatic browning A phenomenon that is being struggled with in the food industry. It plays with factors such as temperature, pH or oxygen to prevent its appearance.
The ripening point of the avocado affects its subsequent oxidation: the more ripe the avocado, the shorter its shelf life. Avocados may also have a weight loss associated with the higher concentration of their fat. All this happens because the avocado continues to breathe after harvest. And it does this by producing. ethylene: a plant hormone that is fully involved in changes in fruit after harvest.
“Avocado is a fruit characterized by its very low carbohydrate and high fat content. Their peculiarity is that they are preferably internal, as they come in whole foods such as nuts, chia seeds, among others. Most often, the concept of “fat” is associated with negative aspects for health or our body. Again, The contribution of the oils obtained from this fruit is healthy as it provides monounsaturated fatty acids that are important for our body and is also rich in minerals such as E, C vitamins and potassium. says María del Rosario Belossi, a nutrition graduate (MN: 10609), sports nutrition and plant-based nutritionist.
“But avocado like any other fruit they have a short shelf life. We are getting used to food lasting much longer in or out of the refrigerator, and often this longer storage is due to an increase in chemical products that the industry often uses to cure or make them more durable,” Belossi adds.
5 tips to prevent your avocado from turning black
1. A squeeze of lemon
Squeeze some lemon into the middle of the remaining avocado after cutting it in half and add the avocado you want to keep. Citric acid lowers the pH, inhibits the activity of the polyphenol oxidase enzyme responsible for oxidation, and therefore takes longer to darken.
“ Lower the pH of the food . pH is a measure of the acidity a compound can have. Lemon is one of those low pH foods, so by adding a few drops of lemon we lower the pH of the avocado and prevent the polyphenol oxidase (PPO) activity from “working” quickly, thereby slowing down the enzymatic activity. you shouldn’t put too much because the enzyme is completely denatured and the food product spoils”, explains Belossi.
2. No to heating
Heat inactivates the polyphenoloxidase enzyme: It is the method used in the food industry to preserve fruits, for example by immersing them in very hot water above 100ºC.
3. Yes to the cold but not too much
At the other extreme, we find the cold. Storing avocados in the refrigerator helps slow down the activity of the polyphenol oxidase enzyme. well Remember to keep half an avocado cold. Also for food safety, because this reduces the proliferation of potentially pathogenic microorganisms.
4. Plastic wrap works
“Although this option is not 100% effective, if we cover the fruit with paper (as long as it is harmless), we are removing the oxygen (the gas the enzyme uses to provide browning). If we cover it hermetically, we try to keep it out of contact and browning happens more slowly,” Belossi explains.
5. The ultimate trick: a tupperware with water
Preserving the avocado in the most suitable conditions is the most effective method and consists of placing one half of the avocado in a container filled with water. In this way, the surface will not come into contact with the oxygen in the air and you will prevent its deterioration. The texture, yes, becomes softer. Ideal for spreading, but less interesting in other preparations.
That’s yes, as long as it lasts 2-3 days in the refrigerator. “With this alternative, it’s about achieving a drop in temperature to reduce the action of the PPO enzyme. Also, the cut side of the avocado is tried to be placed on the water to reduce the contact surface with oxygen. If we also squeeze a lemon, we double the protective effect,” says Belossi.
And the expert concludes: “These tools are not magic. They only slightly reduce the effect of the enzyme. But the most natural thing that can happen is that when the fruit is exposed to oxygen, it turns the typical brownish color of the avocado. If the fruit is stored for days, it is ideal for consumption as it may lose its properties or denature its enzymes, creating unappetizing flavors.” is not.
An avocado a day, the secret formula
A study A study involving researchers from five universities found that eating an avocado a day for six months led to a slight decrease in unhealthy cholesterol levels. Additionally, as a counterpart, they observed that adding this fruit daily had no effect on belly fat, liver fat, or waist circumference in overweight or obese people.
In a randomized study, the team also found that participants who ate avocados had better quality diets over the study period.
While previous smaller studies have found an association between eating this fruit and lower body weight, body mass index (BMI), and waist circumference, this was the largest and most comprehensive study to date on the health effects of avocados. Number of participants and length of work.
Between results Posted in Journal of the American Heart Associationthe authors found “While avocados did not affect belly fat or weight gain, the study still provides evidence that it can be a beneficial addition to a balanced diet.” . Penny Kris-Etherton is a professor of nutritional sciences at Evan Pugh University at Penn State, who was one of the study participants. “Adding one avocado per day in this study did not cause weight gain and also caused a slight reduction in LDL cholesterol, which are important findings for better health.”
Source: Info Bae