Used first Magnetic freezing It’s the Japanese, and they did it to protect the jewel in the Japanese food crown: bluefin tuna. Therefore, most of the equipment sold in Japan is used for freezing fish.
However, they are used to freeze others Everyday foods Especially sensitive to frost, like Bakery dough, sauces, vegetables Oh sushi arrangements.
However, the promising technology of magnetic freezing has not spread significantly in the Western market. In fact, only a few industries and restaurants interested in improving food freezing in Spain have acquired this equipment to test it.
But do they really do what they promise? Do they improve the quality of frozen foods?
The promise of magnetic freezing
A magnetic freezer, according to its manufacturers, produces small amounts of ice on food. This way, it is Keeps cells intact And the food retains its organoleptic properties after the thawing process.
He Industrial secret This allows devices to enter the market without revealing their technical specifications. So factories don’t know the intensity of the magnetic field or the frequencies they use.
How does it work?
In its simplest form, it is a forced air chiller Magnetic field generator.
If these magnetic fields are created by permanent magnets or electromagnets, we will talk about it Magnetic fields stable. If induced using electromagnetic coils, they Magnetic fields oscillate or electromagnetismBy stimuli that are continuous or over time.
Are the ice caps modified?
A fundamental defining factor Organoleptic quality Amount of ice crystals formed during freezing of the product (color, taste, texture, etc.).
Large crystals can damage the structure of foods, causing significant changes in their texture Water loss When de-icing.
Patents and publications of magnetic freezers claim that they prevent formation discharge, that is, water loss after defrosting deteriorates food quality. According to the manufacturers, they achieve this because the magnetic fields applied during the freezing process attract water molecules (“Vibrant“) avoiding their grouping and, with it, the formation of ice crystals.
However, we know that there is more water Dielectric constanthas A little Magnetic sensitivity, that is, it is very insensitive to magnetism. This contradicts the physical foundations on which magnetic freezers are said to be based.
No evidence
Los Results Publications in various scientific journals endorsing this technique are confusing and sometimes even Contradictory. To achieve significant results, more rigorous studies are needed to guarantee reproducibility of results.
It is necessary to compare the effect of freezing in the presence and absence of magnetic fields, under the same processing conditions (wind speed, freezing temperature, etc.) and with a group of suitable samples and their number and cause. Its size, shape and composition.
Temperature, velocity and magnetic fields
The first step in putting them to the test is to characterize these devices thermally and electromagnetically. To do this, we measure the temperature, wind speed, magnetic field intensity and frequency at different points on the frost plates.
In one Commercial equipment was analyzed Oscillating magnetic fields were observed to be very weak (<2 mT), with narrow frequency ranges (6–59 Hz). That is, only two orders of magnitude larger than Earth's natural magnetic field (0.025-0.06 mT).
Our tests on food
Once the magnetic freezer specifications are known, we execute controlled trials, with different magnetic fields, using the same freezing temperature and wind speed. They have been tested Food samples (Aquasolutions Sodium Chloride Y Ferric chlorideDispersions Nanoparticles magnetic) and different Real foods.
In the laboratory, we have used static magnetic fields, low-field alternating electromagnetic fields, and combinations of the former two, which are available in some commercial equipment. In None of our studies found improvement Regarding the quality of frozen foods.
After melting, the water retention capacity and Inside Pork loin Or not inside Crab sticks Frozen with very weak oscillating magnetic fields (0.04- 2 mT 6-59 Hz).
Water loss is also not reduced Inside Minced fish muscle Frozen Application of weak oscillating magnetic fields (7 mT at 50 Hz) or none pieces Potatoes Frozen with high static magnetic fields (150-200 mT).
Unjustified price
If magnetic fields were responsible for all the benefits claimed by the manufacturers of these freezers, this new technology would spread worldwide and represent a significant advance in freezing technology. Not just for food preservation Cryopreservation Biological samples, etc Cells, Tissues and Organs.
So far it seems that the high cost of this equipment is not justified, as scientific evidence is based on the positive effects on food quality. As a result of the powerful mechanical cooling system (-50 °C vs -30°C) And not for the benefits of magnetism.
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**This article was originally published Conversation.
