1. Wash the vegetables, then soak them in water. Use the soaking water to make soup for better flavor.
2. There's no need to thaw frozen vegetables before cooking. Add them directly to boiling water. This makes the vegetables more delicious and preserves more vitamins.
3. Wilted green vegetables can be revived by soaking them in cold water with 1 tablespoon of vinegar for an hour to restore their green color.
4. Soak a whole head of cabbage in salt water to remove small insects from the leaves. Fresh mushrooms soaked in salt water will taste more savory.
5. It's best to cut bok choy with a stainless steel knife, as vitamin C is sensitive to contact with iron. Briefly blanch bok choy in boiling water before cooking to remove its bitterness. Cooked bok choy should not be left for too long, as almost all of its vitamin C will be destroyed after 3 hours.
6. If pickled cabbage is too sour, rinse it once with cold water. Hot water will wash away many of its nutrients and result in poor flavor.
7. When making soup with green vegetables, add salt to the water after it comes to a boil, then add the vegetables. Simmer gently to preserve the vitamin C.