What Do Kiwi and Pineapple Have in Common?

January 8, 2026 •

4 min read

According to scientific research, a key biological feature that kiwi and pineapple share is the presence of potent proteolytic enzymes. This means the main thing that kiwi and pineapple have in common is a group of protein-digesting compounds, which are responsible for many of their unique health benefits and culinary uses.

Quick Summary

Kiwi and pineapple both contain protein-digesting enzymes—actinidin and bromelain, respectively. These enzymes offer shared benefits like enhanced digestion and anti-inflammatory properties, but are different compounds.

Key Points

Proteolytic Enzymes: The primary shared trait is that both fruits contain protein-digesting enzymes, specifically actinidin ($\text{actinidin}$) in kiwi and bromelain ($\text{bromelain}$) in pineapple.
Meat Tenderizing: Both fruits are effective natural meat tenderizers because their enzymes break down tough muscle fibers.
Gelatin Inhibition: Adding fresh kiwi or pineapple to gelatin-based recipes will prevent them from setting, as the enzymes break down the gelatin protein.
Digestive Benefits: The enzymes in both fruits aid in protein digestion, which can help improve nutrient absorption and reduce bloating after meals.
Anti-inflammatory Action: Both actinidin and bromelain have been shown to have anti-inflammatory properties, helping to modulate the body's immune response.
Tingling Sensation: The temporary burning or tingling sensation experienced when eating fresh kiwi or pineapple is caused by the enzymes breaking down protein in your mouth's sensitive tissues.

A Tale of Two Enzymes: Bromelain and Actinidin

While they hail from different plant families, the fundamental commonality between kiwis and pineapples lies in their biochemistry. Both contain unique and powerful proteolytic enzymes, which are enzymes that break down proteins. In pineapple, this enzyme is known as bromelain ($\text{bromelain}$). In kiwi, the enzyme is called actinidin ($\text{actinidin}$). These aren't just minor components; in some green kiwifruit cultivars, actinidin can make up to 40% of the fruit's soluble protein content. This shared enzymatic action is the primary reason for many of their common attributes.

The Science Behind the 'Tingle'

Have you ever felt a tingling or mild stinging sensation in your mouth after eating fresh pineapple or kiwi? This is not an allergic reaction for most people, but rather the effect of these enzymes. Bromelain and actinidin are so effective at breaking down protein that they begin to digest the delicate tissues and mucous membranes inside your mouth, a temporary and harmless effect. This action stops as soon as the enzymes are neutralized by saliva or stomach acid. It also explains why canned or cooked versions of these fruits don't produce the same sensation, as heat denatures the enzymes and deactivates their protein-digesting ability.

Shared Health and Culinary Applications

Because both actinidin and bromelain are natural protein digesters, they have overlapping applications in health and cooking.

Digestive Aid: Both enzymes help break down protein in the digestive tract, potentially improving nutrient absorption and reducing discomfort like bloating after a high-protein meal. Studies on actinidin from kiwi show it can enhance the digestion of proteins from meat, dairy, and legumes. Bromelain from pineapple also has a long history of use as a digestive aid.
Anti-inflammatory Properties: Research suggests that both bromelain and actinidin possess anti-inflammatory effects that can help modulate the body's immune response. Bromelain, in particular, is well-studied for its ability to reduce swelling and pain.
Meat Tenderizer: The proteolytic power of both enzymes makes them excellent natural meat tenderizers. This is a common application for both fruits, where the fresh juice or pulp is used to marinate and break down tough meat fibers.
High Vitamin C Content: While not an enzymatic similarity, both kiwi and pineapple are excellent sources of Vitamin C, a powerful antioxidant that supports the immune system and promotes healthy skin.

The Enzyme vs. Gelatin Phenomenon

Another interesting commonality directly related to their enzymes is how they interact with gelatin. Gelatin is a protein derived from animal collagen. When you add fresh kiwi or pineapple to a gelatin-based dessert, it will not set properly. The enzymes in the fruit break down the protein matrix of the gelatin, preventing it from solidifying. This is a classic science experiment that demonstrates the powerful proteolytic properties of these fruits. As mentioned, cooking the fruit first will destroy the enzymes and allow the gelatin to set properly.

Kiwi vs. Pineapple: A Comparative Look at Their Enzymes


Feature	Kiwi (Actinidin)	Pineapple (Bromelain)
Primary Enzyme	Actinidin ($\text{actinidin}$)	Bromelain ($\text{bromelain}$)
Enzyme Family	Cysteine protease	Cysteine protease
Source for Supplements	Fruit (Actazin®)	Stem
Ideal pH Range for Activity	Broad range (pH 3-10)	Optimal range (pH 6-7)
Key Vitamins	High in Vitamin C, K, E, and Folate	High in Vitamin C and B6
Anti-inflammatory Action	Yes	Yes
Culinary Use (Enzymatic)	Meat tenderizing, prevents gelatin from setting	Meat tenderizing, prevents gelatin from setting

Summary of Shared Characteristics

Both kiwi and pineapple share a unique functional attribute centered around their respective enzymes. These fruits are more than just a source of vitamins and minerals; their bioactive compounds have practical effects both in the human body and in the kitchen. Understanding the role of actinidin and bromelain provides a deeper appreciation for these tropical powerhouses, from their digestive benefits to their ability to prevent a jelly dessert from gelling.

For more in-depth information on the enzymatic properties and potential applications of bromelain and actinidin, an academic review on the topic can be a valuable resource. For instance, the National Center for Biotechnology Information (NCBI) often publishes research on bioactive compounds from food sources like these fruits.

Conclusion

Ultimately, the key thing that what do kiwi and pineapple have in common is a class of proteolytic enzymes that break down protein. While kiwi contains actinidin and pineapple contains bromelain, they both serve similar functions, acting as powerful digestive aids, natural anti-inflammatories, and effective meat tenderizers. This shared enzymatic trait not only gives them a unique mouthfeel when eaten fresh but also influences how they behave in cooking. Knowing this allows for a more informed use of these nutritious and functional fruits in your diet and cooking.

Frequently Asked Questions

The main similarity is that both fruits contain powerful proteolytic enzymes, which are enzymes that break down proteins. In pineapple, this is bromelain, while in kiwi, it's actinidin.

This sensation is caused by the enzymes in the fruit breaking down the sensitive tissues and mucous membranes in your mouth. It's a temporary and harmless effect, not an allergic reaction for most people.

No, while both are proteolytic enzymes, they are distinct compounds. The enzyme in pineapple is called bromelain ($\text{bromelain}$), and the one in kiwi is called actinidin ($\text{actinidin}$).

Yes, both fruits work as excellent natural meat tenderizers. The enzymes in the fresh fruit break down the muscle fibers, resulting in a more tender cut of meat.

The enzymes in the fresh fruit will break down the protein in the gelatin, preventing it from solidifying. If you want to use these fruits in a gelatin-based dessert, you must cook them first to deactivate the enzymes.

No. The enzymes in both kiwi and pineapple are denatured and destroyed by heat, which is why canned or cooked versions of the fruit do not cause the tingling sensation or affect gelatin.

The enzymes aid in protein digestion, which can improve nutrient absorption. Both are also known to have anti-inflammatory properties, and studies have shown potential benefits for immune function.