Translated from: China Food News

It is said that eating more vegetables is beneficial to the body, but fresh vegetables are often difficult to preserve, so frozen vegetables have emerged. But there are also some people who question whether frozen vegetables are still nutritious? Today, let's have a good chat.

The nutrition of frozen vegetables is not poor

Not long ago, the Shanghai Municipal Consumer Protection Commission conducted a test on the differences between fresh and frozen vegetables. They first selected frozen green beans, edamame, frozen broccoli, carrots, shepherd's purse, and corresponding fresh vegetables sold in supermarkets, and sent them to Shanghai Yuanben Food Quality Inspection Co., Ltd. (Shanghai Nutrition Food Quality Supervision and Inspection Station) for testing.

The Shanghai Municipal Consumer Protection Commission simultaneously measured the vitamin C content of frozen vegetables and fresh vegetables, and found that there was not much difference in vitamin C content between frozen green beans and edamame and fresh vegetables. And frozen broccoli and shepherd's purse fillings have less vitamin C content than fresh ones, considering that during the production process, vegetables are cut open and vitamin C will accelerate oxidation.

In fact, vegetables continue to lose nutrients from the moment they are picked. Washing and cutting can accelerate nutrient loss, but freezing can slow down nutrient loss. Considering that fresh vegetables also undergo washing, cutting, and other treatments before cooking, the overall impact of freezing on nutrition is not significant.

In fact, frozen vegetables also use freeze-drying technology. Through freeze-drying technology, food can maintain its original color, aroma, taste, shape, and nutritional content to the maximum extent. Many fruits, vegetables, and other foods can use freeze-drying technology to effectively preserve their nutritional content and taste.

The principle behind frozen vegetables

Most frozen fruit and vegetable products have a standard production process that includes selection, cleaning, peeling and cutting, color protection, blanching, cooling, draining water, and then freezing. The packaging is tested for metal or hair before storage. The blanching process is aimed at removing enzyme activity and ensuring stable product quality.

The specific bleaching process may also involve using steam, microwave, high-pressure, etc. instead of hot water. Subsequent vacuum packaging may also be carried out to remove air and reduce the possibility of oxidation.

Commercial quick freezing can reach temperatures below minus 30 ℃, while ordinary refrigerators at home often cannot reach such low temperatures. This will result in longer freezing time for food, changes in the form of water in the food, which in turn affects the texture of the entire food and makes it easier to lose nutrients.

About 90% of the weight in vegetables and fruits is water, and water and other components are stored in the hard cell walls of plants, providing a supporting structure for vegetables. If the temperature is not enough during freezing, the water in the food will slowly form ice crystals and continuously expand, thereby breaking the cell wall.

Therefore, if it is homemade frozen vegetables and fruits, they will feel softer in texture after thawing, especially frozen tomatoes, which often turn into a paste after thawing.

But if the moisture in the food is relatively low and there are more starch components, the texture changes caused by freezing are not so obvious, typical examples are peas, corn, etc.

Thawing food is not recommended to use water bubbles

Some people like to soak frozen food in hot water, although it thaws quickly,