Can you eat sweet potato vermicelli mixed with cassava flour?

Audit expert: Wang Kang

Director of the National Botanical Gardens Science Museum, Senior Engineer

Recently, sweet potato vermicelli has become a hot topic. Someone bought sweet potato vermicelli online, but the test report showed that there was no sweet potato component in it, but cassava component was detected.

What is the difference between sweet potato and cassava? Is there any harm in mixing sweet potato vermicelli with cassava?

Difference Between Sweet Potato and Cassava

Cassava is a tropical plant. Although it and sweet potato are one word apart, they are two different plants. Cassava is an upright shrub of the Euphorbiaceae family, also known as cassava, manioc, etc. **Cassava is a tree, while sweet potato is a herb. **The rhizome of cassava looks very similar to sweet potato, but it is a woody plant, so it is called cassava.

Pictured: cassava

The rhizome of cassava is rich in starch and protein, and the starch content is much higher than that of sweet potato, 80% of which is starch. Its starch content is 1.0-2.3 times that of sweet potato and 1.0-1.5 times that of potato, the highest among all crops, so it is also called the "king of starch".

Sweet potato, also known as yams, is a plant of the genus Ipomoea batatas in the family Convolvulaceae. The tubers are white, red or yellow.

Sweet potatoes are native to South America and the Greater and Lesser Antilles. They are now widely cultivated in tropical and subtropical regions around the world, but have also been successfully grown in some northern regions such as Heilongjiang Province, and are commonly cultivated in most parts of China.

Pictured: sweet potato

Sweet potatoes are highly adaptable, prefer warmth and lots of light but are not frost-resistant, drought-resistant and alkali-resistant. They are suitable for growing in fertile and well-drained sandy loam and are an easy-to-harvest crop.

Can cassava be eaten?

Cassava is divided into three types: edible cassava, feed cassava and industrial cassava. Among them, only edible cassava is edible for human consumption. The cassava we can buy on the market is generally edible cassava.

We may rarely eat cassava directly in our lives, but cassava starch is very common: the pearls in bubble tea are made from cassava starch as the main raw material.

Cassava has a soft and sticky texture, high yield, low requirements for the growing environment and cultivation level, and is drought-resistant and resistant to barrenness. To put it bluntly, eating cassava is low-cost and can resist hunger. These characteristics have led to the large-scale planting of cassava in areas with backward agricultural levels (mainly in Africa), and it has become the staple food for local people to survive.

Today, cassava is the world's third largest source of starch, ranking just behind rice and corn. According to statistics, cassava is the main food for 800 million people.

Sweet potatoes are low in starch and rich in nutrients such as dietary fiber, vitamin A, vitamin C and potassium, and are considered a healthier choice for weight loss and blood sugar control. Sweet potatoes are more commonly used in food processing such as bread, biscuits, shrimp crackers, and vermicelli.

In terms of nutrition, although cassava vermicelli and sweet potato vermicelli have slightly different tastes, they are both starch-based foods and have similar nutritional values.

Is cassava poisonous?

Raw/fresh cassava is indeed poisonous. But don't worry about the toxicity of cassava vermicelli. In the process of making cassava starch, multiple processes such as soaking, heating, and air drying have removed the toxins in the cassava.

There are two cyanogenic glycoside compounds in raw cassava, one is called linamarin (accounting for about 95%), and the other is called radix rutin. These two substances will produce toxic hydrocyanic acid when hydrolyzed by linamarinase contained in cassava itself. According to data, eating 150g to 300g of unprocessed raw cassava may cause poisoning.

The reason why cassava is divided into three types: edible, feed and industrial cassava, is also based on the content of cyanogenic glycosides. According to the standards of the Codex Alimentarius Commission (CAC), when cassava is peeled, soaked and processed, if the content of cyanogenic glycosides is below 50 mg/kg, it can be classified as edible cassava.

It's no surprise that cassava is poisonous, after all, it comes from the Euphorbiaceae family, which is a "terrible" family, and most Euphorbiaceae plants are poisonous. In addition to cassava, another delicious and poisonous food is taro, which must be carefully peeled, soaked and thoroughly cooked before eating.

In addition to the above methods, fermentation, baking, sun drying, crushing and other methods can also remove hydrogen cyanide from cassava tubers.

Why add tapioca flour to sweet potato flour?

Because it's cheap.

Both sweet potato starch and cassava starch can be used to make vermicelli and noodles. The quality of vermicelli made from sweet potato starch is better than that of cassava starch, but due to the large price difference between the two , in order to reduce costs, some unscrupulous merchants use the lower-cost cassava starch to make "sweet potato noodles".

As early as the 3.15 Gala in 2022, CCTV exposed that many vermicelli manufacturers in Yuzhou used cassava starch and a small amount of corn starch to make "sweet potato vermicelli".

According to CCTV's report at the time, the price of cassava starch was less than 2 yuan per catty, and the price of sweet potato starch was about 4 yuan per catty, a price difference of more than twice.

It should be noted that although cassava can be used as a staple food, it is best not to eat too much at one time.

It has been reported that some people may have enzymes in their intestines that can convert cyanogenic compounds into hydrocyanic acid. Therefore, some people will experience mild poisoning symptoms such as vomiting even if they eat cooked cassava.

References:

Guokr: "Northeast Rain Sister" overturned, is there any harm in mixing sweet potato vermicelli with cassava? "

Popular Science China "Recently popular! Some netizens got "poisoned" after eating... Southerners should pay special attention"