Reasons for soaking lotus root, burdock, udo, etc. in vinegar water

The first purpose is to suppress the action of enzymes that promote the oxidation of polyphenolic substances and prevent browning. In other words, avoid contact with air to prevent oxidation.

Secondly, the pigments called flavonoids contained in vegetables are colorless in acid and turn yellow-brown in alkali. Therefore, the flavonoid pigment becomes colorless when immersed in vinegar water or boiled in vinegar.

These whitening conditions overlap to make the vegetables white.

Another reason for adding vinegar to lotus roots is that the mucin, which is a stringy substance, loses its stickiness with vinegar, making the lotus roots crispier.

Other vegetables that contain flavonoid pigments include cauliflower and onions.