Film on milk. Why does milk foam

2024 Author: Isabella Gilson | [email protected]. Last modified: 2023-12-17 03:14

Remember the film on milk from childhood? Someone liked it, but someone categorically did not want to drink such a drink. Only then we did not know why it was formed. In this article you will find the answer to this question.

Properties of milk

A fresh drink, when shaken on the walls of a glass, does not leave any traces, but a sour product, on the contrary, sticks to the surface of the dish. Particles in milk, stretching in the form of threads, indicate its mucus. You cannot eat such a product.

You should also pay attention to the color of the milk. It should have a white or bluish tint.

If the milk is blue, then it has bacteria in it. The reddish drink most likely contains blood or some kind of microorganism.

When looking at milk under a microscope, you can see a fairly large number of fat droplets that are enclosed in a protein shell. When the drink is heated, they are partially destroyed. In this case, protein folding occurs. You can find out about the next step in the followingsection. It will detail why milk forms a film.

What is milk foam made of?

To put it simply, it's just fat, but more complex in composition. It is composed of minerals, proteins such as albumin, casein and globulin.

As a rule, housewives remove foam from it before drinking. So, a dense film on the surface of the cooled milk is difficult to swallow whole. This is explained by the fact that the colder the drink, the thicker the consistency of the foam becomes.

There are also two types of film on the drink.

One of them is formed during the upholding of whole milk. It mainly contains only fats. The second type of film is obtained by boiling milk.

Foam is formed when the temperature of the drink standing on the stove reaches 50 degrees. Because of this exposure, the milk protein changes its qualities leading to these results.

As a rule, housewives try to get rid of the film on milk at the time of boiling. It is she who covers the entire surface of the drink and does not let air through. When milk boils, rising from the bottom of the pan, he does not find a way out. And then the milk "runs away". You will learn about this process, why this happens and how to prevent this from happening by reading one of the sections of this article.

How does foam form?

When milk boils, proteins (mostly albumin) coagulate. And calcium and phosphorus, which are also in this drink, are converted into insoluble compounds.

Milk fat absorbs the resulting solids and forms a solid film. It can be removed with a spoon in a single layer.

There are recipes in cooking that describe how to dry or freeze such a foam. After that, it is cut into small portions and served.

What will be the thickness of the film on milk depends on the fat content. Most of it in a real whole product. For example, from grandmother's milk to villages. Here, no one processes it in any way, like a store. But there may not be a film on purchased milk.

Harm from foam

No matter how strange it may sound, but it can be. Some people have experienced headaches and nausea, intestinal upset and itchy skin after using this product.

The reason lies in the fact that a person has a lack of lactose. This is an enzyme that breaks down milk sugar in the body.

Another source of contraindications to the use of the drink is individual intolerance to the product. In this case, it is necessary to refuse milk. Also, in case the symptoms persist, it is best to consult a specialist.

When your child does not want to drink warm milk because of the film, you should remove it before you put the drink on the table. It is also possible to replace this product with others such as kefir and yogurt.

What happens when milk turns sour?

In this case, the action of lactic acid bacteria begins. They affect milk sugar,which is subsequently converted to lactic acid. The last component causes protein folding. As a result, some parts of the fat droplets are destroyed. After that, they rise up and unite. Thus, together with protein molecules, sour cream is obtained. If you beat it well, then the fat drops will lose their protein shell and stick together. Then oil is formed.

How to properly wash milk dishes?

In hot water, fat droplets melt and stick to the glass wall. Then it will be difficult to remove it. And cold water, in turn, cannot violate the integrity of fat cells. These residues are easily washed off if the dishes have not been unwashed for a long time and the milk has not dried on its walls.

An interesting fact is that casein, which is formed as a result of milk coagulation, can be used as glue. It is very difficult to clean.

But there is a way to enjoy clean dishes quickly. To do this, a glass with milk residues is first washed in cold water, and then in hot water. Thus, you wash off the fat droplets, and then clean the dishes from other dirt.

Why does milk "run away"?

Have you observed how this boiling process occurs? Maybe yes. But this is not seen in milk. But in the water you can see how, due to the heating of the metal bottom and the walls of the pan, small gas bubbles appear on them. They are formed, as a rule, where there are scratches or traces of fat. The temperature of the water at the bottom and walls is higher, so it is there that it begins to evaporate. Because of this bubblesbecome larger, and at some point float to the surface. The process of boiling water begins when there are more of them.

But when milk is heated, a polymer film is formed. And the higher the temperature of the surface of the drink, the thicker the layer of this formation. Pop-up bubbles do not burst, as happens during the boiling of water, but accumulate under the foam. They stretch it, as a result of which it bursts. At this point, the compressed bubbles expand. After that, the film on boiled milk flies up the pan.

How to stop milk from escaping?

There are several ways to prevent this from happening.

It should be stirred constantly so that a thick film does not form on the milk.

You can also put glass balls or a piece of stainless wire on the bottom of the pan. They will be local boiling zones. It is there that bubbles will form, which will subsequently go up and break through the resulting film on the milk.

Also, you can place a saucer on the bottom of the pot. It should be placed upside down. Evaporation will take place under this cookware. And air bubbles, as described above, will break through the milk film.

How to keep track of a drink that is usually placed in a microwave oven? To do this, the edges of the dishes in which the milk will be should be greased with butter. In this case, the foam will rise to this very border and release bubbles alongedges, such as a saucepan. It is they who will burst here.

If you do not apply the listed intricate tricks, then you need to carefully monitor the milk, otherwise it will “run away”.

After reading this article, you will be able to answer your children's questions about the appearance of a film on milk. This product, due to the content of useful trace elements in it, is very useful for both adults and children.