What is the cassava soup that made Princess Wen Yi vomit milk after eating it in "The Legend of Zhen Huan"?

Recently, making cassava syrup seems to be popular on Xiaohongshu. But isn't this the real culprit that caused Princess Wen Yi to spit up milk in "The Legend of Zhen Huan"?

Image: Cassava syrup | Screenshot from Xiaohongshu

Although the drama claims that cassava flour is non-toxic, cassava itself is actually poisonous.

In the drama, Princess Wen Yi vomited milk after eating water chestnut soup mixed with cassava flour｜TV series "The Legend of Zhen Huan"

What is potato?

Among the 451 Chinese characters that start with the character "艹", quite a few are meant to make people salivate. For example, when we see the character "薹[tái]", we know it means a tender stem; when we see the character "梅", we know it means a juicy berry; and when we see the character "薯", we will definitely feel a sense of fullness. From the day this character was created, it meant "a large lump of starch". At first, it was not used alone, but was used in the word "蓣", referring to the starchy cylindrical tuber of this plant .

Dioscorea batatas, commonly known as yam | Wikimedia Commons

Off topic, yam first appeared in the Classic of Mountains and Seas. In the Tang Dynasty, it was renamed to shuyao to avoid the taboo of Li Yu, the Emperor of Tang. In the Song Dynasty, it was renamed to shanyao to avoid the taboo of Zhao Shu, the Emperor of Song. It is really unlucky that the same name can be tabooed twice. In addition, shu is also a colloquial word for "藷[shǔ]", which refers to sugarcane.

Sugarcane: Actually my name is also shǔ丨Rufino Uribe / wikimedia commons

Except for the Chinese yam, which is native to China, all the yams we know today are imported, and all come from tropical America. The original special word "yams" was given various modifiers to describe the shape, color and taste. Cassava is indeed a shrub , but yams certainly do not grow on trees, but under trees - they are the tuberous roots of this plant.

The most common part of cassava is actually its root tuber. | Amada44 / wikimedia commons

What does cassava look like?

The tubers of cassava grow majestically, with the main root and several main lateral roots swelling together. When dug out of the soil, it looks like a wooden stick with radishes growing all over it.

Cassava root tuber | David Monniaux / wikimedia commons

The above-ground part of cassava can grow up to 3 meters high, with large and obvious leaf scars left behind by the petiole falling off on the lower part of the stem. The leaves are alternate, with long petioles, and the leaves are slightly shield-shaped, palmately divided, with as few as 3 and as many as 9 lobes.

Cassava leaves | CIAT / wikimedia commons

Cassava flowers are monoecious , and the panicles grow at the top of the stem or in the axils of the upper leaves; the flowers at the bottom of the inflorescence are female flowers, with an ovary consisting of three carpels; the flowers at the top are male flowers, with 10 stamens arranged in two circles; both female and male flowers have no petals, only five spotted sepals; the fruit is a capsule with six narrow wings on the surface.

Male flowers of cassava丨Ks.mini / wikimedia commons

Young cassava fruit丨william_tsai / inaturalist

The flowers and fruits of cassava are inconspicuous, but the shape of the leaves is quite beautiful. Therefore, some people in gardening have cultivated variegated varieties whose leaves partially turn yellow due to chlorophyll synthesis disorders for ornamental purposes.

Cassava ornamental varieties with leaves and flowers | Mokkie / wikimedia commons

From the poison family

In taxonomy, cassava belongs to the Euphorbiaceae family. This is a group that is rich in poisons, and cassava is no exception. The whole plant is poisonous . The toxicity of cassava mainly comes from two cyanogenic glycoside compounds, linamarin and linamarin. After they are hydrolyzed by the linamarinase contained in cassava itself, they will release hydrocyanic acid. The toxicity of hydrocyanic acid is self-evident, so cassava cannot be eaten fresh. If you accidentally eat it, you will feel nausea and vomiting at the least, and you will have to delete your account and start over at the worst.

As a member of the Euphorbiaceae family, cassava is also poisonous, but in order to survive, many people still choose to continue to "fight" with this starch-rich poison丨Pixabay

I have always admired those ancestors who looked for food in poisonous plants. They sacrificed countless lives for a bite of food. Of course, in the place of origin, if you don't eat cassava, you may starve to death. Under the dual pressure of toxicity and hunger, the natives of South America 4,000 years ago invented a method to detoxify cassava. It's simple to say, just soak it in water for three to five days and then cook it thoroughly . However, short-term soaking cannot remove the toxicity, and drying is useless. Taoist friends who have tried these methods must have failed to overcome the tribulation.

A woman washing cassava by the river | Wikimedia Commons

It is better to remove the firewood from under the cauldron than to try to stop the boiling water by adding more water. After cassava growers learned how to breed, reducing toxicity has always been an important breeding direction . Modern cassava varieties can be divided into two lines: "sweet" cassava and bitter cassava. The quotation marks are because most of those varieties are not sweet, just not bitter. The tubers of "sweet" cassava are relatively small and the yield is low, but the advantage is that the cyanide content can be as low as 50mg/kg, which greatly reduces the risk of poisoning, and it can be eaten after peeling and cooking. Bitter cassava has large tubers, high yield and starch content, but the cyanide content is as high as 1g/kg, which is a bit suicidal to eat, and it must go through a complicated processing process. In addition, if drought occurs during the growth process, cassava will produce more cyanogenic glycosides for self-defense.

Making cassava grits | Anna Frodesiak / wikimedia commons

It is also the food for many people.

Although cassava is quite troublesome to eat, it is extremely resistant to poor quality and extensive cultivation, and has a huge yield . To exaggerate a little, if you break off a branch and stick it in the soil, it will be full of tubers when you pull it out a year later. Because of this feature, cassava has become the world's third largest source of starch, second only to rice and corn. The latter two have certain requirements for the cultivation environment and management level, while cassava can be cultivated in large quantities in areas with extremely backward agricultural levels. Today, more than 1 billion people in the world rely on cassava for survival, 800 million of whom are in Africa . The country with the highest cassava production is Nigeria, followed by Thailand. As a traditional rice producing area, Thailand's cassava is mainly used for export.

Fried cassava chips | Bdieu / wikimedia commons

Tapioca Balls | Una Smith / wikimedia commons

As a staple food, the advantage of cassava is its high starch content , but the disadvantage is that it only contains starch and no other nutrients. People who eat cassava for a long time need to supplement protein and vitamins, otherwise they are prone to malnutrition. However, areas where cassava is the staple food are usually extremely poor, and the diet lacks protein and vitamins. Therefore, another important direction of cassava breeding is to increase the content of these nutrients.

Cassava can also get sick

Cultivated cassava is threatened by two viruses, cassava mosaic virus and brown streak virus . The former causes cassava leaves to wilt and stop growing, while the latter directly causes cassava roots to rot. In the 1920s, the outbreak of cassava mosaic virus in Africa caused widespread famine; in the 1980s, the virus produced a more powerful variant in Uganda that could cause all cassava leaves to fall off. Currently, the main method for preventing and controlling these two viral diseases is to produce virus-free seedlings using tissue culture methods.

Cassava mosaic disease | Patrick Chiza Chikoti / Plant Disease

However, this method is too extravagant for extremely poor areas, and it can only treat the symptoms but not the root cause. The ultimate means is to cultivate virus-resistant cassava varieties, but it is difficult to achieve this by relying on traditional breeding methods, and biotechnology must be relied on. At present, with the support of international organizations and the efforts of scientists, the cultivation of genetically modified virus-resistant cassava has seen the dawn. It is a great charity to use advanced technology to ensure the food rations of more than one billion poor people.

Cassava Brown Streak Disease | Paulo Ernesto Meissner Filho / Researchgate

Around the Daoguang period of the Qing Dynasty , cassava was introduced to China via Southeast Asia. At that time, the cassava introduced was mainly bitter cassava, and since it could only be grown in subtropical areas, it has always been a very marginalized crop. It was used as a supplement when food was insufficient and helped people survive famine. Today, China's cassava production ranks 15th in the world , most of which is used to extract starch, and a small part is used as feed. Chinese cassava breeders (chī) (huò) are not satisfied with traditional cassava that is complicated to process and has low nutritional value, and have cultivated cassava varieties that can be eaten raw. I have seen the representative "South China No. 9", which is golden yellow because it is rich in carotene, which is very strange. As for toxicity, anyway, I can still write after eating it raw.

Author: Gu Yourong

This article comes from GuokrNature (ID: GuokrNature)

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