Why do green leaves shrink greatly once cooked?

Because the high temperature during cooking destroys the cell wall and cell membrane of biological cells, the liquid in vacuoles loses and vegetables become smaller.

All vegetables and fruits will have the problem of nutrient loss after cooking, because most of the vitamins C, B and minerals in vegetables are water-soluble, which are easily destroyed by oxygen and high temperature, or dissolved in water during boiling. Secondly, the amount of nutrients retained in vegetables after cooking is related to cooking methods. The longer the heating time, the more water is used for cooking, which is also the main reason for nutrient loss.

British research found that the loss of anti-cancer substance sulfide in broccoli is directly proportional to cooking time. Scalding broccoli for 5 minutes, sulfide loss 15%, 10 minutes 40%, 30 minutes 77%. Cai Xiaorong, a nutritionist at Taian Hospital, explained that this is also because the sulfide mentioned in the study is water-soluble, and it is easy to be destroyed when cooking at high temperature for a long time, and it is soluble in water.

Absorbent paper packaging:

Wrap the green leafy vegetables in the kitchen with absorbent paper, and then cover them with a fresh-keeping bag to seal them, so that you can put the green leafy vegetables in the refrigerator, which can ensure that the water in the refrigerator will not lose water so quickly, and the water in the refrigerator will not soak into the vegetables, avoiding pollution, producing no bacterial impurities, and the green leafy vegetables will not rot. This method can last for about four or five days at most.