Why is it so bitter when you take a bite of cucumber? That's the cucumber crying for help!

Some cucumbers are very sweet when you take a bite.

Some cucumbers are really bitter when you take a bite.

They are all cucumbers, but why are some cucumbers so unconvincing and have to be bitter gourds?

Where does the bitter taste of cucumbers come from?

Cucumber is a cultivated species of the genus Cucurbitaceae, native to northern India on the southern foothills of the Himalayas.

As a food that is deeply loved by the public, cucumber contains rich nutrients such as vitamin C and carbohydrates. It can be eaten raw, stir-fried, or pickled. It has a variety of cooking methods and is a high-quality and inexpensive vegetable crop.

But we always eat some bitter cucumbers. Where does this bitterness come from?

Cucurbitacin, also known as bitter element, is the main reason for the bitterness of cucumber. Cucurbitacin is a tetracyclic triterpenoid compound, including cucurbitacin A, cucurbitacin B and other types.

Cucumbers contain different types of cucurbitacin in different developmental stages and different tissues and organs: cucurbitacin B is contained in the roots of seedlings, cucurbitacin B and cucurbitacin C are contained in the cotyledons that have not yet fully expanded, and only cucurbitacin C is contained after the cotyledons are fully expanded. Its bitter taste is used to prevent insect infestation.

After a long period of breeding, the fruit generally contains very low levels of cucurbitacin, which humans cannot taste.

Cucurbitacin in cucumber helps cucumber resist diseases and pests, and is involved in regulating the growth and development of plants and adapting to adverse environments. Its biosynthesis pathway is shown in the figure below.

Image source: "Effects of water treatment on cucumber physiology, quality and bitterness-related gene expression"

Since the bitter substance content in cucumber fruits is relatively small and difficult for people to taste, why are some cucumbers bitter or even so bitter that they cannot be eaten?

Bitterness is its survival strategy

If cucumbers taste bitter, it may be due to their variety.

There are many varieties of cucumbers, some of which are wild cucumbers. Wild cucumbers are also called bitter cucumbers, which are native to India. Their fruits contain more bitter substances, so they taste very bitter. Not only are they bitter, but they can also be used as laxatives...

Nowadays, whether it is the cucumbers sold on the market or the cucumbers grown by buying cucumber seedlings or growing them yourself, they are all wild varieties that have been domesticated. Generally speaking, they are crisp, sweet and very delicious.

But bitterness may occasionally appear. This is because under poor growing conditions, some cucumbers will experience "atavism", which is related to genetics.

Image source: hippopx

In addition to the atavism phenomenon of some varieties, malnutrition and insufficient light during the growth period of cucumbers may cause the cucumbers to taste bitter.

Cucumbers have relatively high requirements for nutrients and sunlight during their growth period. Insufficient water, poor soil texture, excessively poor soil, and lack of fertilizer will increase the bitter substance content in cucumbers.

When there is insufficient light, the plant's photosynthesis weakens and the photosynthetic products decrease, which in turn leads to poor plant growth and easy accumulation of bitter substances, which also increases the bitter substances in the fruit.

During periods of low temperature and low light, especially when there are continuous rainy days, the root system of cucumbers will not grow well. When the roots are damaged or poorly developed, the absorbed water and nutrients will be reduced, causing the cucumbers to grow slowly and accumulate more bitter substances in the lower part of the cucumbers.

Image source: pexels

Insufficient sunlight and continuous low temperatures will affect the development of cucumber plants, making them bitter. In addition, continuous high temperatures will also make cucumbers bitter. The absorption function of the root system is weakened under high temperature conditions, cucumbers grow slowly, and the chlorophyll content of the leaves decreases or dries up. Moreover, under continuous high temperatures and droughts, more bitter substances accumulate in cucumbers, making them too bitter to swallow.

Image source: Author

In addition to the reasons mentioned above, cucumbers can also become bitter due to excessive nitrogen fertilizer.

Applying too much nitrogen fertilizer during the process of topdressing cucumbers will lead to an excess of nitrogen. On the one hand, it will easily increase the bitter substances in the cucumbers, and on the other hand, it will easily cause the plants to grow too tall. When the cucumbers are not set evenly, the cucumbers grown on side branches and weak branches are more likely to taste bitter.

Image source: Author

Finally, excessive spraying of pesticides can also cause cucumbers to taste bitter!

Can bitter cucumbers be eaten?

Cucumbers are bitter, and most of them probably end up in the trash, because they are hard to swallow. But some people think that although they are a bit bitter, they are not bad, so can they be eaten?

It is best not to eat too much bitter cucumbers, because bitter substances can irritate the stomach and intestines, and eating too much can cause nausea or even vomiting.

If the pesticides on the cucumbers are not cleaned off, they will make the cucumbers bitter and are not good for human health. Therefore, be sure to clean the cucumbers you buy!

So, do you know why cucumbers are bitter? This is the survival strategy of cucumbers~

References:

[1] Yi Jianqun. Effects of water treatment on cucumber physiology, quality and bitterness-related gene expression[D]. Anhui Agricultural University.

[2] Xiong Fei. Why do cucumbers taste bitter? [J]. Agricultural Consultants, 2012, 000(001):13-13.

[3] Anonymous. Why cucumbers sometimes become bitter[J]. New Countryside, 2018.

END

Review expert: Shi Jun, PhD in Botany

Tadpole Musical Notation original article/reprint please indicate the source

Editor/Xiao Xitushuo