In addition to processing food such as stewing bones, boiling meat… when we make tea, pour beer, we will also see a thick layer of air bubbles floating on the surface of the liquid. Many people think that it is dirt, which needs to be removed. However, there are also mixed opinions around this.
Why is the bubble layer produced when we process food?
To understand why bubbles are created when stewing or boiling foods, you first need to know what “surface tension” is.
Surface tension is the force exerted by liquids such as water, to make the surface as small as possible. Simply put, it is the contraction force of the liquid surface.
The foam itself is a nutrient.
Pure water has a large surface tension and large liquid surface shrinkage force, which is not easy to foam. As for broth, soup, thin porridge, the surface tension is small, it is easy to create air bubbles floating on the surface.
When processing food, organic substances such as proteins, carbohydrates … in food will be dissolved and dispersed in water, reducing the surface tension of the liquid. This creates a continuous, dense and stable foam during the cooking time.
The answer is yes. The foam itself is a nutrient . Food creates foam because it contains organic matter, dissolves in water and creates foam when we use spoons and chopsticks to stir, stir.
In addition, in that layer of air bubbles also contains some fat-soluble nutrients such as fat-soluble vitamins: Vitamins A, D, E, K.
This foam has a certain nutritional value, but it is not without basis to say that this foam is a dirty substance.
Besides, the foam layer created when brewing tea contains saponins, which have antibacterial, blood lipid regulation and cardiovascular protection functions. Similarly, the foam layer when cooking soy milk also contains saponins, which have antioxidant, immunomodulatory and anti-atherosclerotic functions.
Although this layer of air bubbles has a certain nutritional value, it is not unreasonable to say that this layer of foam is a dirty substance. Let’s analyze it further to get a clear answer.
Does the layer of air bubbles created when processing food have harmful ingredients?
As described above, the bubble layer contains organic matter and some good fat-soluble nutrients. But they may also contain some harmful fat-soluble substances.
Air bubbles appear when we boil bones, boil meat.
For example, drugs such as antibiotics, pesticides, etc. and other ingredients in food can also take the opportunity to enter the foam. This is also an issue that worries many people. But at present, there is no research data on harmful substances in the air bubble layer when cooking, whether it is harmful to human health or not.
If the processed foods are grown and nurtured by your own hands, without the use of agricultural drugs, you absolutely do not have to worry about toxic substances, rest assured to enjoy the nutritional value of the air bubble layer.
Most foam is created by foods such as meat when they are boiled. This happens due to residual blood, residue layer, protein denaturation at high temperature . This foam has a clear, raw meat smell, which will affect the actual appearance and taste of the dish.
Therefore, this layer of foam should be removed. As for the white foam layers that are produced afterwards, they do not need to be removed, they can be kept.
When cooking soy milk, a lot of foam is produced due to the rich content of saponins in soybeans . Therefore, this layer of air bubbles should not be removed.
The correct method is to reduce the temperature, or add a few drops of cooking oil and continue cooking for a while. This will help the protease in soy to limit the action of anti-nutrients. From there, soy milk will be more delicious and nutritious.
Some people worry that the air bubbles in purine-rich beer increase uric acid production, but this is not true. The beer foam is made up of protein, the carbon dioxide in the beer makes up , and the beer itself is a low-purine beverage. So you don’t have to worry about the beer foam when pouring beer.