Tofu dregs are fermented when they are covered with straw to cover up the white hairs. The fermented tofu dregs can be used as noodle sauce. It tastes good and has high nutritional value.

Tofu dregs has undergone a fermentation process. Its sweetness comes from maltose, glucose and other substances produced during the fermentation process, and its umami taste comes from the amino acids produced by protein decomposition. Noodle sauce contains a variety of flavor substances and nutrients, which not only tastes delicious, but also enriches the nutrition of dishes, increases edibility, and has the effect of appetizing and feeding.