How desirable it is to have a bowl of mung bean soup that clears heat and detoxifies on a hot summer day, but why is the mung bean soup cooked by most people always red and unappetizing? To solve this problem, the leaders of Wangjingxiyuan Siqu Community, an innovative science popularization community in Beijing, invited Song Tianle, a science popularization teacher from Capital Normal University.
Teacher Song instructed the residents to boil two pots of water. After the water came to a boil, they put the same amount of mung beans in each pot to cook. One pot was covered with a lid, while the other was left uncovered. After 5 minutes, they checked again. In the uncovered pot, the color of the mung bean soup gradually deepened and turned red; whereas the soup in the covered pot was a vibrant green.
Regarding this, Teacher Song explained that the green color of the mung bean soup is mainly due to the skin of the mung bean.