Recently, it's cassava season. On a social platform, "tapioca syrup" has become a high-frequency word, and many netizens posted photos of homemade tapioca syrup, commenting as: "It's so delicious that it flies, and it's particularly addictive one bite after another......
The picture comes from the Internet
But some netizens are suspected of being poisoned after eating:
The picture comes from the Internet
Cassava, really poisonous
There are three types of cassava: food, forage, and industrial cassava. Among them, only edible cassava can be consumed by humans. But don't worry, the cassava we can buy in the market is generally edible cassava.
So, is it safe to eat cassava? No, no.
Let's start with the conclusion: raw/fresh cassava is indeed poisonous. The toxicity comes from two cyanogenic glycosides in raw cassava, one called linnicin (about 95%) and the other called rhizoside [1], which produce toxic hydrocyanic acid when hydrolyzed by the linitalinase contained in cassava itself. If you are a level 10 player in "The Legend of Zhen Huan", you must still remember the famous "tapioca flour incident", the bitter almonds that An Lingrong used to commit suicide, and the toxin is also hydrocyanic acid.
According to some data, eating 150g~300g of untreated raw cassava may cause poisoning.
The reason why cassava is divided into three types: edible, forage and industrial cassava is also distinguished according to the content of cyanogenic glycosides. According to the standards of the Codex Alimentarius Commission (CAC), when cassava is peeled, soaked and other processing, the content of cyanogenic glycosides in it is less than 50mg/kg, it can be classified as edible cassava.
It is not surprising that cassava is poisonous, after all, cassava comes from the Euphorbiaceae family, which is a "terrible" family, and Euphorbiaceae plants are generally poisonous. In addition to cassava, taro is another delicious and poisonous food, which must be carefully peeled, soaked and thoroughly cooked before eating.
In addition to the above methods, hydrocyanic acid can also be removed from cassava tubers by fermentation, baking, sun exposure, and crushing.
If it is dangerous, why can cassava still be used as a staple food?
Although cassava is toxic when eaten raw, a fact that cannot be ignored is that the starch content of cassava is as high as 70%~80%.
The taste is soft and glutinous, the yield is large, but the requirements for the growth environment and cultivation level are very low, drought tolerance and barrenness, to put it bluntly, the cost of eating cassava is low, and it can resist hunger, these characteristics make cassava in the agricultural level of backward areas (mainly in Africa) is planted in large quantities, and has become the staple food for local people to survive. Cassava is now the world's third-largest source of starch, behind rice and corn. According to statistics, cassava is the main food ration for 800 million people.
However, due to the fact that most of the cassava is starch and the nutrients are very single, eating a large amount of cassava for a long time can easily cause a lack of high-quality protein, vitamins and other nutrients.
Data from: Chinese Food Composition Table (6th Edition)
Cassava is low in protein, but higher in potassium, vitamin C and vitamin B1 than rice and steamed bread, which is related to the fact that cassava is less processed than rice and wheat, which are the raw materials of rice and steamed bread. For example, when cassava is processed into cassava flour, the protein content is only 0.08g/100g, and the vitamin C and vitamin B1 content are 2.96mg/100g and 0.007mg/100g, respectively.
Because the detoxification treatment is more troublesome and the nutritional value is not too high, people generally do not choose cassava as a staple food in developed agricultural areas. But as long as it is a delicacy, the Chinese have always been not afraid of a little poisonous, just like pufferfish, and then a variety of Yunnan mushrooms, in front of foodies are not too much of an obstacle, let alone just "stomach-up" cassava.
All kinds of "sugar water" made of cassava are very popular in many areas in the south, and the "pearls" in taro balls, mochi and milk tea made of tapioca starch are also very popular.
How to enjoy delicious food safely?
If you want to enjoy cassava food healthily, safely and quickly, it is recommended that you pay attention to the following points:
Choose the right breed
Mainland agricultural scientists have bred low-toxicity cassava varieties such as "Huanan 9", "Guire 10" and "Gui Cassava 11".
However, even if it is a low-drug species, do not consume a large amount of it at one time, in addition to the toxicity problem, you should also consider the calorie problem caused by eating a lot of starchy food.
Peel and soak, cook thoroughly, and don't eat too much at once
Tapioca peels are high in cyanogenic glycosides, which can be reduced by peeling them and soaking them in water for a long time (some say they should be soaked for 1 week with daily water changes).
It is also cooked thoroughly when it is made. High-temperature heating inactivates enzymes that convert cyanogenic glycosides, making them unable to convert cyanogenic glycosides into toxic hydrocyanic acid. Therefore, cooking it thoroughly is an important method for detoxifying cassava. It should be noted that when boiling cassava, the lid should be left open to allow the converted hydrocyanic acid to evaporate.
It is also important to note that you should not consume too much at once. It has been reported that some people may also have enzymes in their intestines that can convert cyanogenic glycosides into hydrocyanic acid, so some people will experience mild poisoning symptoms such as vomiting even if they eat cooked cassava.
Buy tapioca flour directly
This method is more non-toxic and easier to process into a delicacy.
Finally, I would like to recommend a simple and easy-to-make winter cassava delicacy~
Taro egg custard
Raw material:
Tapioca flour, sweet potato puree, white sugar, eggs, wolfberry, dried osmanthus
Steps:
1. Add an appropriate amount of white sugar to tapioca flour and sweet potato puree in a ratio of 2:1 and mix well. You can add an appropriate amount of water or milk to knead into a non-sticky dough. Roll the dough into thin strips and cut into small pieces of the right size, slightly shape and knead into a circle. Add water to the pot and bring to a boil, add the taro balls to cook, then remove the cold water for later use.
2. Pour water into the pot again and boil, beat the frangipani, put in the taro balls and wolfberries and cook for 1~2 minutes after cooking, you can add white sugar according to personal taste, sprinkle with dried osmanthus after serving, and you can enjoy.
This taro egg custard is made up for by the lack of high-quality protein in cassava and sweet potatoes. If you have time, you can also use a pressure cooker to cook red beans in advance and add them to the taro egg custard to further increase the content of minerals and dietary fiber, and also make this dessert richer in taste.
Editor: Gan Zhuoran Xi Chen Jiexuan