Why does mung bean soup have red and green colors

The red or green color of mung bean soup is mainly related to the acidity and alkalinity of the water, the degree of oxidation, and the cooking time. Red mung bean soup is usually boiled in alkaline water or iron pots, while green mung bean soup often appears in neutral water for short periods of time. When mung beans are boiled in weakly acidic or neutral water, the chlorophyll in the bean skin is retained, and the soup color appears clear yellow green. In this state, mung bean soup has a better cooling effect and is suitable for quick consumption in summer. Boil in a clay pot or stainless steel pot with purified water for 10-15 minutes to maintain a good green color. At this time, the degree of oxidation of polyphenolic substances in mung beans is low, and the antioxidant components are more fully preserved. When the water quality is alkaline or boiled in an iron pot, the polyphenolic substances in mung beans will combine with metal ions to form complexes, and the soup color gradually turns orange red to deep red. Long term boiling can also accelerate polyphenol oxidation and deepen the color of the soup. This type of red mung bean soup has a softer texture and more complete dissolution of some B vitamins, but its cooling effect is slightly weaker. Due to the alkaline water quality in some northern regions, traditional boiling methods are more prone to red soup bottoms.

It is recommended to choose the boiling method according to your needs. For relieving heat, priority should be given to short-term boiling green soup, while for nourishing purposes, you can choose long-term boiling red soup. No matter what color of mung bean soup, excessive sugar should be avoided. diabetes patients are advised to drink the original soup. Soak mung beans in the refrigerator for 2 hours before boiling, which can shorten the boiling time and better preserve the nutritional components.