Many people enjoy drinking fruit juice, but they worry about nutrient loss during the process. In fact, even juice consumed immediately after being juiced will lose a significant portion of its nutrients. For instance, vitamin C must not come into contact with various oxidizing enzymes, as they will react with each other. However, when juicing, the high-speed blades completely destroy the cells, mixing all their contents together. As a result, vitamin C encounters multiple oxidizing enzymes, leading to a natural loss of nutrients. Nevertheless, blanching the fruit before juicing can help reduce this nutrient loss.
Eating fruit is a common practice, but drinking it as juice is considered quite fashionable. However, after buying a juicer, many people have the same questions: Does juicing result in nutrient loss? How should I juice properly? And how long can the juice be stored? Cucumber juice loses 80% of its vitamin C
First, even juice consumed immediately after being juiced will lose a significant portion of its nutrients.
This is because the cells of fruits and vegetables have complex ultrastructures. Think of it like a building with many rooms, each with a different function and containing different items that should not be mixed. For example, vitamin C must not meet various oxidizing enzymes, or they will react with each other. But when juicing, the high-speed blades completely destroy the cells, mixing everything together. Thus, vitamin C encounters multiple oxidizing enzymes and suffers heavy losses. An experiment conducted by one of my students showed that the destruction rate of vitamin C in cucumber juice can be as high as 80%, with similar results for tomatoes, bok choy, and others.
In addition to vitamin C, antioxidant components such as flavonoids and anthocyanins will also be lost to varying degrees. As for insoluble fiber, it naturally does not end up in the juice. Insoluble elements like calcium are also left in the pulp. If possible, it's best to consume the pulp along with the juice.
Blanching before juicing preserves nutrients
Many people don't realize that in commercial fruit and vegetable juice production, the produce is often blanched. This means the fruits and vegetables are briefly scalded in boiling water to "kill" the oxidizing enzymes and slightly soften the tissue before juicing. This not only reduces the loss of vitamins but also increases the juice yield and results in a more vibrant color that is less likely to turn brown. This is especially important for vegetables without a sour taste, such as carrots, greens, celery, and sweet corn, which must be blanched before juicing.
As for the feeling of fullness that comes from eating whole fruits and vegetables, this cannot be retained no matter how you juice them. Therefore, for those trying to lose weight, it's better to eat them whole, as juicing is not an ideal option. Freshly squeezed juice can be stored for up to one day
If not blanched, the juice should be consumed immediately after juicing and not stored. You could say that every minute, the loss of vitamins and antioxidant components increases. If the juice is made from blanched produce, the enzymes have been inactivated, so it can be stored in a sealed container in the refrigerator for about a day. However, try to minimize the juice's contact with air to prevent oxidation and browning.
Blanched juice turns brown very easily. Turning brown does not mean it is toxic or harmful; it is still drinkable. It only indicates that the health-promoting polyphenols in the fruits and vegetables have been oxidized upon contact with oxygen, and their antioxidant effects will be somewhat reduced. At the same time, the flavor will also change during storage, losing its original fresh and delicious taste.