What should I add to mashed potatoes to keep them from turning red?

The water in which raw potatoes are soaked contains starch, polyphenolase and other substances. After the polyphenol enzyme oxidation reaction, there is a chemical reaction called browning. This chemical reaction not only appears on potatoes, but also turns black after apples are cut.

Antioxidants can be added to prevent enzymatic browning of polyphenols, and commonly used antioxidants include sulfite and vitamin C. Even as an antioxidant, sulfite is a strong inhibitor of enzymes.

Sulfite is a food additive, which has been widely used in the world for a long time. Can be used as food bleaching agent and preservative; Can inhibit non-enzymatic browning and enzymatic browning, prevent food browning, prevent fruits from blackening, and prevent fresh shrimps from producing black spots; It is also a very effective antibacterial agent in acidic medium. The maximum dose shall not exceed 0.05g/kg.