1. Steaming for too long: If the corn is already too old or dry, it will take longer to steam, but this will also make the texture of the corn older.

2. Storing too long: If the corn has expired or has been stored for a long time, it will become older.

3. not cooking long enough: if the corn is not cooked, it becomes older.

4. Improper storage: if corn is stored in an environment that is too hot or damp, it will deteriorate and become older.

Therefore, to avoid aging of corn, the following measures can be taken:

1. Buy fresh corn and determine the proper steaming time according to its variety and size.

2. Avoid storing corn for too long and consume it as soon as possible after purchase.

3. Make sure the corn is fully cooked when cooking.

4. Store corn in a dry, ventilated environment at the right temperature.