Why do i use alum for pickle?

Alum is used in pickling to help maintain the crispness and firmness of fruits and vegetables. It works by strengthening the pectin in the cell walls, which prevents them from becoming mushy during the pickling process. Additionally, alum can enhance the overall texture of the pickles, ensuring they remain crunchy while absorbing flavors from the brine. However, it's important to use it in moderation, as excessive alum can be harmful.