Are frozen fruits and vegetables more nutritious than fresh ones?
Grassroots Influence New Vision Tian Chunhui
In most people's eyes, fruits and vegetables are naturally better the fresher they are, but is this really true? Related studies show that different fruits and vegetables undergo different changes in nutritional composition before and after freezing.
In supermarkets or vegetable markets, if you want to buy fresh strawberries and vegetables, people generally do not choose to go to the frozen food aisle. Frozen fruits and vegetables often look less fresh after thawing, which makes people feel that once food is frozen, some of its nutritional value is lost. Therefore, people usually believe that the fresher the fruits and vegetables, the better for human health. Does this view really match the facts? On the other hand, fruits and other foods preserved by freezing can be supplied all year round and are relatively cheap. Fresh fruits and vegetables are only sold in large quantities during peak season, transported to various stores for sale, and after people buy them and take them home, they are generally stored in the refrigerator, for as little as a few days or as long as several weeks. However, we all want to know: compared with fresh fruits and vegetables, do frozen fruits and vegetables have the same nutritional value?
In the early 1920s, Clarence Birdseye invented quick-freezing technology. After that, many people tried to improve freezing technology. The Inuit in Alaska used rapid freezing to store fresh fish to prevent spoilage. Clarence Birdseye followed the Inuit practice of freezing food, so that large ice crystals would not form and damage cells or destroy the food's original taste. Vegetables and fruits contain 70% to 90% water. Once they ripen, the water is quickly lost, they are also attacked by microorganisms, and enzymes break them down, making them extremely prone to spoilage.
Today, freezing technology is continuously improving; for example, food is blanched before flash freezing. No chemicals are produced during the frozen storage process. If you are worried that fruits and vegetables will lose nutritional value after freezing, then remember that fresh fruits and vegetables also lose nutrients. Ali Bouzari of the University of California and his colleagues conducted a study in which they compared eight vegetables and fruits (corn, broccoli, spinach, carrots, peas, green beans, strawberries and blueberries), and then analyzed the differences in nutritional composition between the fresh and frozen forms of these eight vegetables and fruits, and did not find consistent, regular differences.
After freezing, the vitamin content in corn increases, while the vitamin content in green beans and blueberries decreases. After broccoli is frozen, the riboflavin (a type of vitamin B) in it increases. In contrast, the riboflavin content in fresh peas decreases after freezing.
In another paper, the relevant researchers studied the fiber and mineral content (magnesium, calcium, iron and zinc, etc.) of fruits and vegetables before and after freezing. The results showed that there were no obvious changes in the fiber and mineral content of the above eight fruits and vegetables before and after freezing.
People who like frozen vegetables and fruits believe that freezing prevents food from spoiling. If fruits and vegetables are placed in a high-quality refrigerated compartment and kept undisturbed, they can maintain their original state, and their minerals and vitamins will not be lost either. Loving the taste of fresh vegetables and fruits is a subjective feeling. But freezing naturally has its wonderful uses; for example, when the head is bumped and a lump swells up, frozen peas can be used at this time to reduce the swelling, and their swelling-reducing effect is much better than that of fresh peas.