Lotus root and pork ribs soup is a traditional home-cooked dish. Its main raw materials include lotus root, pork ribs, ginger slices, salt, etc. This vegetable soup is delicious and the lotus root tastes pink and glutinous. It is a very popular dish.

When cooking lotus root and pork ribs soup, we will find that the lotus root usually turns pink after being cooked. This is because lotus root contains a substance called lotus root, also known as lotus root browning factor. Lotus root element is a phenolic substance. When lotus root is affected by cutting, cooking, oxidation and other external factors, lotus root element will change, causing the color of lotus root to change.

The change of lotus root element is due to the fact that there is a group called "enol" on the benzene ring in the lotus root element molecule, which has strong reducing property. When the lotus root molecule is stimulated by the outside world, the enol group will undergo an oxidation reaction to form a compound called "quinone". Quinone molecules can react with other groups on the benzene ring to form a new compound called a "browning product." These browning products can make lotus roots appear pink or reddish brown.

When cooking lotus root and pork ribs soup, the lotus root turns pink mainly due to the combined effect of the following factors:

Heating: Heating is the main factor that causes the lotus root to change color. When lotus roots are cooked at high temperatures, the lotus root molecules are stimulated by heat and are prone to oxidation reactions, thus forming quinone molecules. At the same time, heating can also convert the starch in lotus root into sugars, and the sugars further react with lotus root elements to form browning products.

Oxygen: Oxygen is also an important factor causing the discoloration of lotus roots. During the cooking process, oxygen molecules dissolved in the water can oxidize with lotus root elements to form quinone molecules. In addition, if you use an iron pot or other metal pot to cook lotus roots, metal ions may also undergo oxidation reactions with lotus root elements, causing the lotus roots to change color.

Enzymes: Lotus roots contain a variety of enzymes, one of which is called polyphenol oxidase, which can oxidize phenolic substances into quinone substances, causing the lotus roots to change color. During the cooking process, if the cut lotus roots come into contact with oxygen, polyphenol oxidase will take effect and accelerate the discoloration of the lotus roots.

To reduce the degree of discoloration of lotus roots in lotus root pork ribs soup, you can take the following measures:

Pretreatment: Soak the cut lotus roots in water with lemon juice or white vinegar. It can prevent lotus roots from coming into contact with oxygen, thereby reducing the degree of discoloration of lotus roots. In addition, heating can also destroy the activity of polyphenol oxidase and reduce the degree of discoloration of lotus roots.

Cooking: When cooking lotus roots, use non-iron pots such as casseroles and stainless steel pots to avoid contact with metal ions. In addition, adding a little baking soda or white vinegar when boiling lotus roots can neutralize the acidic substances in the water and prevent the lotus roots from changing color.

Material selection: Choose fresh, tender and crisp lotus roots, and avoid choosing lotus roots that are yellow or dark in color. In addition, choosing lotus roots with intact epidermis and no damage can reduce the chance of contact between lotus roots and oxygen.

In short, the reason why the lotus root in the lotus root pork rib soup turns pink is due to the change of lotus root elements under the action of external factors such as heating, oxygen and enzymes. Adopting appropriate pre-treatment, cooking methods and material selection can reduce the degree of discoloration of lotus roots.