As far as I know, pickling is for dehydration and preservation. Dehydration is an important step in the production of mustard tuber, which mainly includes wind dehydration and salt dehydration. After adding salt, the water in the mustard tuber will be soaked out quickly. Since it is dehydration, it is of course necessary to squeeze out the water. Salt dehydration is not as good as wind dehydration, and the high salt content is harmful to the body, but now there are also low-salt processes. In addition, wringing out the salted water will also remove some ingredients that affect the taste of mustard tuber, which is similar to removing water from cooking, so it is not bitter.