1. Boil the lotus root first: In order to keep the lotus root white, another method is to blanch the lotus root with boiling water for 70 seconds, which can inactivate the polyphenol oxidase in the lotus root, thus inhibiting the process of transforming polyphenols into quinones. However, this method is only suitable for lotus root stew soup, which will make its taste worse and lose its crisp and tender feeling when used in cold lotus root slices.

2, white vinegar soaked lotus root slices: In addition to high temperature treatment, proper addition of acidic substances can also bind the hands and feet of polyphenol oxidase. For example, adding vinegar can largely avoid the catalytic effect of polyphenol oxidase and keep the lotus root white. Method: Prepare a pot of cold water, put a certain amount of white vinegar in the cold water, and soak the lotus root in it for a while. Acidic substances can inhibit the catalytic effect of polyphenol oxidase, so that lotus root will not turn black and discolor and keep its white color.

3, salt water soaked lotus root slices: lotus root is easy to be oxidized and discolored by air after being cut and peeled. The best way to avoid this situation is to isolate the lotus root from oxygen before frying, so in order to prevent discoloration, soak the cut lotus root slices in clear water or salt water to prevent the lotus root slices from turning black.

4. Don't cook lotus roots with iron: Lotus roots must not be cooked with iron. Lotus roots in iron pots will turn black more easily than those in stainless steel pot. The blackening of lotus root fried in iron pot is related to polyphenols contained in it. These guys have the same properties, that is, they can combine with iron ions to form purple or blue complexes. Gallic acid is one of the abundant polyphenols in lotus root. It combines with iron ions to form a blue-black substance, which is the main component of blue-black ink. So don't cook lotus root with iron.