Sales of frozen foods have skyrocketed during the epidemic! What is the nutritional value of frozen foods? Is it worth buying?

During the epidemic, many people stayed at home and stocked up a lot of food, including vegetables, fruits, rice, steamed buns, etc. If you ask what kind of food is everyone's first choice, I think many people will buy some quick-frozen dumplings, quick-frozen meat and other quick-frozen foods.

Recent data shows that the sales of quick-frozen food on major platforms have skyrocketed, and the sales of seafood meatballs have increased more than ten times. In addition, quick-frozen fish, meat, shrimp, and quick-frozen dumplings in supermarkets have become popular items. My family also bought some quick-frozen vegetables, such as quick-frozen peas and corn kernels.

However, there are always people who are worried about the poor nutritional value of frozen food and are unwilling to eat it. For example, my father is now in his hometown in Hubei. It is difficult to buy meat and vegetables in the town. I asked him to buy some frozen dumplings to stock up. My father refused to do so. In his eyes, frozen dumplings are junk food, poor in nutrition and not delicious. He would rather not eat meat than buy frozen dumplings.

What is the nutritional value of quick-frozen food? Can we stock up on it? Can we eat it without worry? Today we will talk about the nutrition of quick-frozen food.

01For quick-frozen food, speed is the key!

Many people think that frozen food is poor in nutrition and that the nutrients are lost if it is frozen for too long. In fact, this is a complete misunderstanding.

Quick-frozen food is not just about freezing food. Its biggest feature is that it freezes very quickly.

If we put the homemade dumplings in the refrigerator to freeze, because the temperature drops relatively slowly, the water in the food will form "ice crystals". As the temperature drops, these "ice crystals" will become larger and larger, which can easily destroy the cell structure of the food, leading to nutrient loss and making the taste worse.

Quick-frozen food uses a unique freezing process - fast. Compared with the general freezing process, it can quickly reduce the temperature of food to a temperature far below the freezing point of water (usually below -18°C). Due to the rapid cooling speed, the water in the food will enter a "supercooled" state. The "ice crystals" formed at this time are very small, so small that they will not seriously damage the food cells, and can retain the nutrition and taste of the food to the greatest extent.

We can compare "quick freezing" to Quicksilver, which is so fast that the food doesn't have time to react before the freezing operation is completed, and there is almost no significant loss of nutrition.

Moreover, due to the low temperature, cell activities are basically stopped and the activities of microorganisms are greatly restricted, so frozen foods can be preserved for a long time.

02In terms of nutrition, frozen foods are not bad!
Although there are many types of frozen foods, including various dumplings, snacks, meatballs, and frozen fruits and vegetables, from the perspective of raw materials, they can be roughly divided into frozen animal foods and plant foods, which we often call frozen meat and frozen fruits and vegetables.
(1) Frozen meat

Meat mainly provides protein and minerals. Under extremely low temperature conditions, protein and minerals will not change, so the nutritional value of frozen meat will hardly change or be lost.
However, the problem with frozen meat may be that the taste may be slightly worse, because if it is frozen for a long time, the meat will gradually lose water and the taste will not be as tender.
(2) Frozen fruits and vegetables In addition to traditional frozen meats, quick-frozen dumplings, and steamed buns, frozen vegetables are also common in supermarkets. From classic frozen green beans, carrots, and corn to quick-frozen broccoli, asparagus, and greens, the variety is becoming more and more diverse.

What people are most worried about is frozen vegetables and fruits. Because most people think that fresh vegetables and fruits are more nutritious. However, this is not what you think.
When fruits and vegetables are picked, they are still carrying out biochemical activities such as respiration. Before entering supermarkets and farmers' markets, they have to go through processes such as transportation and storage. Finally, they reach consumers' homes. They often have to travel a long distance, so nutritional loss is inevitable.
However, frozen fruits and vegetables do not lose more nutrients than fresh fruits and vegetables. Frozen fruits and vegetables are quickly frozen at -18 degrees Celsius after being picked. At this temperature, the respiration of fruits and vegetables is almost stagnant, and microorganisms cannot grow and reproduce, which may even help retain nutrients.
Many studies have found that quick-frozen fruits and vegetables have their own nutritional advantages:
The United States Department of Agriculture once conducted a survey on vitamin C, B vitamins, polyphenols, carotenoids, etc. in common fruits and vegetables on the market. The results showed that although there were differences in certain nutrients between frozen vegetables and fresh vegetables, there was no obvious overall difference between frozen and fresh. In some cases, the preservation rate of nutrients such as vitamin C, B vitamins, carotenoids in frozen fruits and vegetables is even higher.

Scientists at Sheffield Hallam University in the UK studied 37 products and found that there was not much nutritional difference between fresh and frozen foods. The study also found that after frozen green beans and fresh green beans were cooked, the beta-carotene content in frozen green beans was even higher.

Because of this, many authoritative health organizations in the world believe that the nutritional value of frozen foods is not much different, and both can be part of a healthy diet.
for example:
The US FDA has evaluated that frozen foods have no significant difference in nutritional value and may even be better;
The British Nutrition Foundation believes that there is no difference in nutritional value between frozen and fresh foods, and because frozen fruits and vegetables are often frozen immediately after harvesting, they may even contain more vitamins than fresh fruits and vegetables.
The National Library of America (NLM) also believes that although the nutritional value of quick-frozen foods and frozen foods may be slightly different, there is no significant difference overall.

Considering that food is not very convenient to obtain during the epidemic, frozen food can be a good choice and it is also a good nutritional supplement.
03Too much oil and salt? It’s not exclusive to frozen foods

Although the nutritional value of frozen foods is no different from that of ordinary foods, many people are still worried that frozen foods are unhealthy. There are also rumors that frozen foods contain a lot of fat and salt.
In fact, this worry is completely unnecessary.
The nutritional value of quick-frozen food is no different from that of ordinary food, and it can be a part of a healthy diet. As for the salt and fat issues that people are worried about, it is true that some quick-frozen foods, especially quick-frozen meatballs and dumplings, often have more fat and salt for the sake of good taste, and eating too much may not be good. However, this is not a problem unique to quick-frozen foods.
In fact, in order to make the food taste better, almost all food companies will add more oil and salt when processing food. This is even more true in restaurants. Many people also like to add more oil and salt when they cook at home.
If you are worried about the oil and salt issues, it is recommended that you read the food labels carefully when choosing frozen foods, and choose products with less oil and salt. Also pay attention to the balance of diet when eating. If you know that the food contains a lot of oil and salt, try to eat less.

04How to choose frozen foods?

There are many kinds of frozen foods in supermarkets. How do you choose the right ones?
(1) Pay attention to whether the sales environment has intact freezing conditions. The main factor that affects the nutritional value of quick-frozen food is not the quick freezing itself, but the cold chain storage in the sales chain.
Generally, quick freezing requires that the food cannot be thawed during the entire storage process. However, in many places, the cold chain cannot be guaranteed, and it is impossible to prevent freezing and thawing.
The biggest problem with freeze-thaw is that it causes microorganisms to multiply in large numbers, affecting the nutritional value and safety of quick-frozen foods.
Therefore, when buying frozen food, you should first check the freezing conditions of the sales venue and see if the freezer or refrigerator is in good condition. If it is not in good freezing condition, it is best not to buy it, let alone those that are obviously thawed.
(2) Pay attention to the brand and shelf life. Generally speaking, big brands are more reliable in terms of quality. When purchasing, read the product name, manufacturer address, production date and shelf life on the packaging bag.
Although quick-frozen foods have a long shelf life, you should still choose products that are close to the production date. When eating, try to finish the quick-frozen foods that are close to the expiration date first.
(3) Carefully observe the state of quick-frozen food. Fresh quick-frozen fish, meat, shrimp, dumplings or vegetables have uniform texture and no ice or ice crystals in the packaging. However, if the temperature fluctuates during transportation and storage, water will be transferred and large ice crystals will form. The products inside may stick together and more and more ice crystals will appear in the packaging. At this time, the quality of the product has been significantly reduced, and the taste and flavor will be greatly reduced.
Therefore, when choosing quick-frozen food, you should carefully check the condition of the product. If you see ice crystals and adhesion, you should be cautious when buying it. If you buy it home, you should eat it as soon as possible and not store it for too long.
04How to store frozen food?

(1) Put it in the freezer as soon as possible to prevent it from melting due to heat during transportation. If you cannot eat it immediately, put it in the refrigerator immediately. After putting it in the refrigerator, you still need to eat it as soon as possible, because frozen food has a shelf life, and the quality will deteriorate if it is left there for too long.
(2) When storing, different foods should be stored separately. Different foods should be packaged and frozen separately to avoid being placed together with other raw fish, meat, poultry and other products. This is because different foods stored in the same space will spread bacteria and cause food spoilage. Opened or damaged frozen foods should be eaten as soon as possible. If you can't finish them, seal them tightly or wrap them in fresh-keeping bags and put them in the refrigerator.
(3) Divide the food into portions according to the amount you want to eat and avoid repeated thawing. Before eating, divide the food into portions according to the amount you want to eat and thaw as much as you want to eat to avoid repeated thawing.

References:

[1]American Heart Association. Fresh, Frozen or Canned Fruits and Vegetables: All Can Be Healthy Choices![2]US National Library of Medicine. Foods - fresh vs. frozen or canned.[3]EUFIC. Are there nutritional differences between fresh and frozen berries?[4]Ali Bouzari, et al. Mineral, Fiber, and Total Phenolic Retention in Eight Fruits and Vegetables: A Comparison of Refrigerated and Frozen Storage. J Agric Food Chem. 2015 Jan 28;63(3):951-6.[5]Ali Bouzari, et al. Vitamin Retention in Eight Fruits and Vegetables: A Comparison of Refrigerated and Frozen Storage. J Agric Food Chem. 2015 Jan 28;63(3):957-62.[6]Men Jianhua, Bian Lihua, et al. Effects of soft freezing conditions (-7℃) on the nutritional content of animal foods. The 6th Academic Symposium of the Public Nutrition Branch of the Chinese Nutrition Society and the Proceedings of the Changes in the Diet and Nutritional Status of Chinese Residents, 2005.