Why does an apple darken?
Apples are one of the most beloved and common fruits in the world. There are many varieties and varieties of apples - fruits can vary in color, size, shape, flavor accents.Despite this diversity, all varieties of apples are united by one unpleasant feature - the fruits darken at the cut. It is worth figuring out why this happens, what is the true cause of the assumption, and what is only people's speculation, how to deal with undesirable oxidation processes.
Myths
One of the most popular answers to the question of why an apple darkens at a slice is that the air, namely the oxygen in its composition, provokes the active oxidation processes of the trace element iron (or ferum), which apples are so rich with. Other assumptions of "popular thinkers" follow from this. So, they say, if after cutting the apple does not darken, then it is obvious that it contains too little iron and this fruit does not have a large number of useful properties or is artificially grown.
At first glance, this seems quite plausible and even scientifically based, but in practice it is not. The fact is that the amount of iron contained in apples cannot be oxidized in any way so as to change the color of the pulp of the fruit. Nutritionists proved that A 100 gram apple contains about 1–2 milligrams of iron.
Real reasons
It is worth considering the true prerequisites of this chemical process. First you need to study the full composition of trace elements, vitamins and minerals that apples are rich in. So, the composition of the fruit (in addition to components useful to the human body) includes the following:
- antioxidants, namely polyphenols;
- enzymes, oxidizing polyphenols;
- quinones - substances resulting from oxidation.
To study the darkening of the fruit at the cut, such substances as quinones should be considered in more detail. Colorless quinones are inherently oxidizing, being on the surface of the apple slices, they immediately begin to interact with all environmental substances. That is why the apple darkens (substances resulting from this interaction give the fruit a brown tint). The catalyst for this process, obviously, is air, or rather oxygen. Many are interested in the question of why, why, and for what purpose these processes occur. Everything is simple - darker, the apple seems to be "protected" from the attacks of harmful insects.
Imagine a situation: a caterpillar penetrated into an apple and gnawed a hole in it. If the apples had no protective mechanism of darkening, then these lesions would slowly “seep” into the fetus until it completely rotted. But the resulting brown shade film “heals” the damage and “saves” the fruit from further damage.
It is worth noting that different varieties of apples or even individual fruits of one variety darken at different speeds, which is associated with the saturation of a particular fruit with polyphenols or quinones. Nevertheless, some constant trends are traced. So, sweet apples are covered with a brown film much faster than sour ones.
Interesting! This process occurs not only in the cut of fresh apple, but also in other fruits and vegetables: bananas, peaches, potatoes, mushrooms and others.
It is important to remember that darkening of fruits and vegetables on the cut is a natural process. If this does not happen, then, most likely, the fetus yielded to chemical processing or is a genetically modified product.
How to prevent?
If we approach this issue scientifically, it becomes clear that in order to avoid an undesirable reaction, it is necessary to remove any of the elements from the reaction formula. It should be immediately clarified that it is impossible to get rid of polyphenols, which play the role of antioxidants, especially since they are beneficial to humans. It is logical to assume that it is necessary to “remove” oxygen from the reaction. To do this, apples can be coated with a special wax, which is done on some farms and factories.
But this wax is harmful to the human body, so it should be thoroughly washed off before eating the fruit. Otherwise, there may be disorders of the digestive system, up to serious poisoning.
And also at the moment, the possibility of exclusion from the apple composition of the enzyme that oxidizes polyphenols is being studied. However, this process is in an experimental phase, as a result of which chemists hope to bring out a variety of so-called perpetual apples. If the question of combating a brown crust appearing on an apple slice is approached from the point of view of an ordinary man in the street, then everything becomes much simpler and clearer. So, professional chefs have long since figured out how to prevent an undesirable process. To do this, you need fresh lemon or lemon juice, which you need to sprinkle the pulp of the fruit. The oxidation process will not stop completely, but will noticeably slow down.
For such purposes, sugar syrup is also suitable, which you need to abundantly lubricate the cut pulp.
If you plan to transport the cut apple, then you need to ensure its airless storage in a vacuum bag or in extreme cases in an airtight container, sudochke or other container. Thus, the phenomenon of darkening of the apple on the cut has a deep chemical nature. Therefore, do not believe the popular myths and popular legends. It is important to always get to the bottom of the true causes of phenomena, including natural ones. To slow down the undesirable darkening process, you can use folk methods or just eat the whole fruit.
About why apples darken and how to avoid it, you will learn from the following video.
