Storing Vegetables for a Long Time
Fresh vegetables, if bought and left uneaten at home, will gradually lose some vitamins. For example, when spinach is left at 20°C for a day, it loses up to 84% of its vitamin C. To preserve vegetables, they should be stored in a place that is away from light, well-ventilated, and dry.
Discarding the Vitamin-Rich Part
For instance, when eating bean sprouts, some people only eat the sprouts themselves and discard the bean halves. In fact, the bean halves contain 2-3 times more vitamin C than the sprouts. Another example is when making vegetable dumplings, squeezing out the vegetable juice causes a loss of over 70% of the vitamins. The correct method is to mix the chopped vegetables with oil first, then add salt and seasonings. This way, the oil coats the vegetables, preventing the filling from releasing liquid.
Stir-fried Bean Sprouts with Vermicelli
Simmering over Low Heat
Vitamins C and B1 are both sensitive to heat and prolonged cooking. According to studies, vegetables stir-fried over high heat lose only 17% of their vitamin C, but if they are then simmered, the vitamin C loss can reach 59%. Therefore, it's best to cook vegetables over high heat. This not only preserves the color and flavor but also minimizes nutrient loss. Adding a little vinegar during cooking also helps preserve vitamins. Some vegetables, like cucumbers and tomatoes, are best eaten raw in salads.
Not Eating Cooked Vegetables Immediately
Some people, to save time, like to cook dishes in advance and keep them warm in the pot until everyone is ready to eat, or reheat them for the next meal. During this warming process, vitamin B1 in vegetables can be lost by 25%. Cooked cabbage, for example, loses 20% of its vitamin C when kept warm for 15 minutes, an additional 10% after 30 minutes, and another 20% after an hour. If vitamin C loss during cooking is 20%, and another 25% is lost into the cooking water, keeping the dish warm for another 15 minutes would cause an additional 20% loss, totaling a 65% loss. This leaves very little vitamin C remaining in the vegetables.
Eating Vegetables but Not the Broth
Many people love to eat vegetables but not the cooking broth. In fact, when cooking, most vitamins dissolve into the broth. For example, after stir-frying bok choy, 70% of its vitamin C is in the broth. When fresh peas are boiled in water for 3 minutes, 50% of the vitamin C leaches into the water.
Cutting Vegetables Before Washing
When washing and chopping vegetables, if you cut them first and then rinse them, a large amount of vitamins will be lost into the water.
Having a Preference for Stir-fried Vegetables
Some people, in an effort to lose weight, avoid fats but have a preference for vegetables stir-fried with meat. Recent research has found that watery vegetables have air-filled cells, while meat cells are filled with water. Therefore, vegetables are more absorbent of oil. A serving of stir-fried vegetables can often contain more oil than a serving of fried fish or fried ribs.
Mushroom oil