Be careful! Pineapple is DIGESTING your mouth!

Pineapple was very popular and cheap in Queen Victoria Market last month. As for me, I like pineapple very much and I bought a lot. Pineapples contain a variety of nutritious such as fiber, organic acid, vitamin B1 and C and potassium and so on. Most importantly, the Vitamin C in pineapple is 5 times as much as it in apple and VC is extremely helpful for maintaining our skin shiny and bouncy.

Figure 1: Usually, the pineapple will sweeter if the surface of it is completely yellow. In the meantime, the unfavorable taste will decrease. Image by KAYUM photography via Flickr.

But many people don’t like the pineapple for the reason that it will make our mouth tingling. To be honest, I am also a victim of this pineapple’s property. Because our human is not the only one who fascinated with the pineapple, it is regarded as a delicious meal for a lot of animals like pigs and monkeys and so on. To protect themselves, they put a chemical called bromelain in their fruits. Bromelain is a chemical that helps pineapple break protein molecules to digest them.

Figure 2: The Bromelain can be also used in cooking. If we want to make the meat more easy to crew, we can mix Bromelain with meat befor cooking. It will help degrade the muscle fibers since the fibers in meat are also made up with protein. Thus, it will make the meat softer. Image by Chuck DeLoy via Flickr.

Many tissues of animals (for example the skin of our mouth) are mainly make of protein. When we chewing the pineapple, the bromelain can break the skin and tissue in our mouth in a very high speed. In other words, the Pineapple is digesting out mouth. It will make the skin in our mouth thin or even make us bleed.

Though we don’t have to worry about it since that is not very serious and we can repair ourselves. It is still an unfavorable sensation when we are enjoying such a sweet fruit. The key point is dealing with the bromelain.

Bromelain’s nature is protein and we already have bunches of methods to deactivate proteins. The bromelain is very fragile, it can only work properly in the environment with the pH of 5-8 and the temperature should be around 37 oC. If the condition changes, the bromelain will strike or even die, and the tingling feel will disappear.

To change the pH, we can put the pineapple pieces in vinegar for a couple of hours, since the pH of vinegar is about 1. The acid in vinegar will break the structure of bromelain and, thus, deactivate it. Or we can also put the pineapple into our stomach directly by opening our belly instead of letting them go through the mouth. Because the liquid in our stomach is also very acidic. But I’m pretty sure these are not good ideas.

Well…How about heat the pineapple? It does help. Many of the cuisines in Southeast Asia use pineapple as an ingredient. Pineapples also act as the sour source instead of vinegar. Pineapples are very commonly used in pizza making as well. However, once heated, the pineapple will be no longer crunchy. To avoid this pity, people have to try other methods.

Figure 3: Pineapples are commonly used in cooking in some Asia countries. Image by Brian Tao via Flickr.

Somebody says ‘why not slice it first and put them under the salt water?’.

Yes! That is almost a common sense. But, does it really make sense? To keep flavor and break the bromelain, toxic heavy metal ions will also help, such as Mercury, Cadmium, Lead, etc. Because these ions will react with proteins and deactivate them. (That is also the reason why they are toxic.) The chemical name of salt is ‘Sodium Chloride’. Sodium, also a kind of metal ion, is non-toxic because it is so stable that it can hardly interact with protein. In other words, they are useless in destroying the bromelain.


However, it makes sense in some ways. Salt can make the cells on the tongue that sense sweetness more sensitive. So that we can feel sweetness better and numb feeling will be depressed in comparison. For the same reason, salt can be added in coffee in Turkey and be added in watermelon in Japan.

Figure 4: It is really incredible that the salt can be added in coffee to highlight the sweetness. Image by Kay Ficht via Flickr.


I’m really happy that so many readers like my blog. Science exist everywhere in our daily life. They are just standing behind every simple questions, like ’why one second is as long as a ‘tick’ on the clock’ ‘how did people know the distance between sun and earth in the past’ etc… If there is anything you are interested in, just tell me in the comments!

4 Responses to “Be careful! Pineapple is DIGESTING your mouth!”

  1. ipermatasar says:

    yeah, we just take it for granted that pineapple taste like that without knowing the scientific reason behind it. by the way, have you ever heard that pineapple is not good for pregnant women? maybe you know the reason why

  2. Yue Li says:

    An interesting blog. I love this last paragraph. Even though we know lots of ‘common sense’, we rarely ask why and thus we miss the chance to improve it. As long as I know salt is not really helpful, I’ll try vinegar next time. Thanks for sharing this knowledge.

  3. Christina Crachi says:

    Thanks for the interesting blog post- I try to eat pineapple quickly due to this problem!
    I suppose you could use pineapple juice similar to lemon juice then in terms of ‘cooking’ raw meat?
    A few grammatical errors, so just check your next blog post thoroughly before posting!

  4. Rachel Caddy says:

    My singing teacher always swore by pineapple for recovering from throat infections, but after trying it I always struggled with the sensation on the lips….now I know why! Thanks for giving me insight into this topic, it was well explained and super interesting.