Why Pineapple Bites Back - The Science Behind the Sting

Imagine you're enjoying a slice of fresh pineapple. You take the first bite, which is sweet and tangy. But then, you notice something odd - a slight tingling on your tongue. A gentle burn spreads in your mouth. You might wonder what's happening. You've just experienced the pineapple sting, an interesting side effect of this tasty fruit. 

Don't worry, though. It's not harmful, just a bit of science at work in your mouth. Let's explore why pineapple bites back and what's really going on when you eat it.

What causes it?

Two things team up to create this weird sensation. First, pineapples have tiny, needle-like crystals called raphides. They make small cuts in your mouth. It's like getting dozens of paper cuts on your tongue, but from something even finer than paper. ^₍₁₎

Then comes the real factor causing it which is an enzyme called bromelain. This enzyme breaks down proteins. When it gets into those tiny cuts, it starts breaking down the proteins in your mouth. In simple terms it eats the protein in your mouth or lip area. This is in turn causes that burning or stinging sensation. ^₍₂₎

How to avoid it:

Cook the pineapple: 

Heating the pineapple denatures the enzyme bromelain that causes the sting.₍₃₎ You may grill, bake or slightly saute it on pan to do the same.

Soak it in salt water: 

Soaking the pineapple pieces in a salt water solution for approximately 10-15 minutes before consumption can reduce the sting. 

Use canned pineapple: 

Canned pineapple is already processed and heated, which prevents the stinging sensation.

Chose a ripe pineapple:

Unripe or raw pineapples contain more bromelain than ripe pineapples, causing a greater stinging sensation. Opt for a golden yellow pineapple with a sweet smell  at its base. ^₍₄₎

Conclusion

Although pineapple can cause this stinging sensation, it's not harmful to your health. The amount of protein broken down in your mouth is very small, and your body quickly heals these tiny cuts. The discomfort is temporary and usually goes away soon after eating.

If you find the sting bothersome, remember there are several ways to reduce or avoid it.In the end, you can enjoy your pineapple without worrying about the sting being harmful. It's just part of the unique experience of eating this tropical fruit.

References

1. Hale, Laura P., et al. "Bromelain Treatment Alters Leukocyte Expression of Cell Surface Molecules Involved in Cellular Adhesion and Activation." Clinical Immunology 149, no. 1 (2013): 1-12. https://pmc.ncbi.nlm.nih.gov/articles/PMC3951349/. Accessed February 9, 2025.

2. Biocatalysts Ltd. "Bromelain: Food Applications." Biocatalysts Ltd., n.d. https://www.biocatalysts.com/media-resources/bromelain-food-applications. Accessed February 9, 2025.

3. Science Meets Food. "Bromelain in Pineapple." Institute of Food Technologists Student Association (IFTSA), n.d. https://sciencemeetsfood.org/bromelain-in-pineapple/. Accessed February 9, 2025.

4. Vita World. "What is Bromelain?" Vita World 24, n.d. https://vita-world24.de/en/blog/What-is-bromelain. Accessed February 9, 2025.

By Dr. Iqra Momin