What happens when I freeze a food?

Freezing is a preservation method that allows us to extend the shelf life of food, too. In addition, it is considered a fairly safe technique, since it exerts changes on food products at a physical and chemical level in such a way that microbial growth stops. Attention! it just stops, as freezing does not eradicate microorganisms like sterilization does. After, when the food is thawedEspecially if we keep them at room temperature, the microorganisms reproduce again and can cause foodborne infections.

Given the all foods have water To a greater or lesser extent, we can say that when a food freezes, logically, the water it contains is no longer liquid and forms ice crystals. These crystals will be smaller the higher the freezing rate or larger when the freezing speed has been slower (which is what happens at the domestic level). When larger crystals form the structure of food can be adversely affectedFor this reason, some products will withstand very well that we freeze them at home and others will not.

Tips for Freezing Food

Now that we know that freezing is a process that will have certain repercussions on the food, and that its thawing can carry health risks, it is important to take these into account 6 recommendations on according to the Spanish Agency for Consumption, Food Safety and Nutrition ():

• Pack the products in small portions since, in this way, the freezing will be faster and will entail less food risks. This makes it easier to freeze, but also allows better organization of the servings.
• Airtight plastic freezer bags are very useful for packaging. Must be used just one time and it is advisable to remove as much air as possible. On the other hand, it must be taken into account that when food is frozen it expands, so a proportional space must be left to prevent the containers from exploding.
• The criterion "First in, First out" or "the first thing that comes in is the first thing that comes out" must be used, so note the freezing date In the bags or containers it will help us to know which products we should consume first.
• The duration of food in the freezer will be determined by the stars of the home freezer. For more information on the duration of these products do not forget consult the indications manufacturer's preservation.
• If you freeze food after cooking, don't forget let them cool before putting them in the freezer; By introducing them hot, you can adversely affect the temperature of others.
• We must not refreeze food, since successive freezes, reduce the quality of the food and facilitate its contamination.

Foods that resist freezing

Freeze we can freeze everythingHowever, there are some foods that can lose their organoleptic characteristics due to freezing (color, flavor, texture and aroma). We speak for example of:

Cooked potatoes

The structure of the starch contained in potatoes means that after freezing they can have a floury or grainy texture that we will not find it too appetizing. We are talking about freezing in a conventional home freezer, not with the technology available in the food industry, that is another story.

Creamy cheeses

In this case also the structure will notice the frostbite. The creamy cheese paste, once thawed, will crumble much more, losing the unctuousness and creaminess that characterizes it, and therefore losing organoleptic qualities.

Raw fruits and vegetables

At the domestic level, we must take into account that freezing and thawing causes a significant water loss and, with this, the crunchy texture they have is lost. For this reason, when we want to take a food of this type raw and with bites, freezing is not a good option. In the case of cooked vegetables if we will have better results, while, in fruits, freezing may be a good idea if we are going to crush it to make an ice cream or a smoothie.

Fried

It is once again the case of foods that lose their crunchiness, while a battered and fried food that we eat when finished will be crunchy, and only the fact of consuming it later will already subtract qualities from its texture, if we also freeze the loss of organoleptic quality is going to be older.

Boiled eggs

First of all, we must take into account the increase in size, so if we freeze an egg with the shell it will break. On the other hand, the texture of a boiled egg is also will deteriorate with freezing, while if raw, we beat it and keep it in airtight containers, it will freeze better.

Mayonnaise or other sauces

In the case of chemically complex foods, such as the emulsions that are formed when making some sauces, mayonnaise or aioli, for example, this balance that the emulsion maintains is going to be broken, which we would translate as the sauce it cuts, or is unbound.

• When we freeze a food, the water it contains crystallizes forming ice crystals that will be smaller or larger depending on the freezing speed.
• Food degradation processes are slow down in freezing, but the microorganisms they contain are not totally stopped or killed.
• Some foods can tolerate freezing poorly, seeing altered aspects such as their texture, its flavor or its color.

Bachelor of Food Science and Technology Diploma in Human Nutrition and Dietetics