Debunking the Blueberry Myth: More Blue Fruits Exist
Blue is one of the rarest colors found in nature, especially within the world of fruits and vegetables. For many, the sight of a blueberry is the only experience they have with a naturally blue food item, solidifying the idea that it's a unique botanical specimen. However, a deeper dive into the world of edible plants reveals that the humble blueberry has several chromatic companions, from lesser-known berries to exotic fruits and even some cultivated varieties of common staples.
The Science Behind Blue and Near-Blue Fruits
Many so-called 'blue' foods, including blueberries themselves, don't actually contain a pure blue pigment. Their coloration is often a complex interplay of pigments and structural features. For example, anthocyanins are water-soluble pigments responsible for red, purple, and blue hues in plants. The final color depends on the pH level of the fruit's cells. A recent discovery highlighted that a waxy coating on a blueberry's skin is what scatters blue and ultraviolet light, making the fruit appear blue to our eyes. Scrape off the wax, and the fruit's dark red pigment becomes more visible.
Other Notable Blue Fruits
Here is a list of some other fruits that can be considered blue:
- Bilberries: Often called European blueberries, these berries are similar to their American cousin but are smaller and have a stronger, sweeter taste. Critically, bilberries have blue flesh, unlike the pale green interior of highbush blueberries.
- Concord Grapes: While often described as purple, Concord grapes have a very deep, bluish-purple skin. They are rich in anthocyanins and resveratrol, making them a heart-healthy choice.
- Damson Plums: A type of plum with a deep blue to purplish skin and a tart flavor. They are excellent for making jams and sauces.
- Sloe Berries: The fruit of the blackthorn tree, these small, blue-black berries are too tart to be eaten raw but are famously used to make sloe gin.
- Huckleberries: A close relative of blueberries, huckleberries vary in color depending on the species, but many have a deep blue, almost black, hue.
- Blue Java Banana: Also known as the “ice cream banana” for its creamy texture and vanilla-like flavor, this unique banana variety has a beautiful pale blue-green skin before ripening.
- Honeyberries (Haskaps): These elongated, oval-shaped berries have a deep blue skin and a juicy, tangy-sweet flavor profile reminiscent of a mix between blueberries and raspberries.
- Blue Tomatoes: While technically a vegetable in a culinary sense, the fruit of certain tomato varieties, like 'Blue Bayou' or 'Indigo Ruby', develops a dark, bluish-purple skin due to high levels of anthocyanins.
Blueberries vs. Bilberries: A Comparison
| Feature | Blueberries (Highbush) | Bilberries (European) |
|---|---|---|
| Appearance | Large, plump berries with a pale green or whitish interior. | Smaller, darker berries with a deep reddish-purple interior. |
| Color Source | Waxy bloom on the skin scatters light; internal flesh is light. | Pigments in both the skin and the flesh give a true blue/purple color. |
| Taste Profile | Mildly sweet and juicy. | More intensely flavored, tart, and sweeter. |
| Availability | Widely available in supermarkets worldwide. | Primarily found in Europe and Asia, sometimes wild-foraged. |
| Health Benefits | High in antioxidants, particularly vitamin C and anthocyanins. | Very high in anthocyanins, often associated with promoting eye health. |
The Scarcity of the Color Blue in Edible Plants
Blue is not a color that many plants utilize in their fruit for a simple evolutionary reason: visibility to seed-dispersing animals. Red, orange, and yellow fruits stand out vividly against green foliage, making them easy targets for birds and mammals to spot, eat, and spread the plant's seeds. The color blue is less contrasting in nature, which may explain why it's a less common choice for edible fruit, though certain structural colors, like the waxy coating on blueberries, make them appear brighter to birds that see into the UV spectrum.
Beyond fruits, some vegetables also exhibit a blue color, including blue corn, Adirondack blue potatoes, and certain varieties of cabbage and carrots. Even some edible mushrooms, like the Indigo Milk Cap, are naturally blue. However, the edible part of these plants can often be purple or multi-hued, with the blue being more of a surface feature.
Conclusion
While blueberries have long held the title of the quintessential blue fruit, they are not alone. The world is filled with a fascinating diversity of naturally blue or bluish fruits, each with its own unique flavor profile and nutritional benefits. From the intense color and flavor of the wild bilberry to the curious pale-blue skin of the Blue Java banana, the fruit world offers a colorful array of options for those willing to look beyond the familiar. The story of blue fruits is one of evolutionary strategy and the surprising science behind natural coloration, revealing that even in the rarest colors, nature offers a wealth of variety.
Expanding Your Blue Horizon
To incorporate more blue into your diet, consider adding elderberries to syrups or teas, cooking with blue tomatoes for a nutritional boost, or experimenting with jams made from sloe berries or honeyberries. The vibrant hues add visual interest to meals while providing a rich source of antioxidants and other nutrients.
Frequently Asked Questions
Q: What makes fruits turn blue? A: Most naturally blue or purple fruits get their color from a type of antioxidant pigment called anthocyanins. The specific color depends on the pH of the fruit's cell sap. Some, like the blueberry, also use a structural color from a waxy surface coating.
Q: Are bilberries and blueberries the same? A: No, they are different species, though related. Bilberries are native to Europe and have a darker, more intensely flavored flesh than the lighter, milder highbush blueberries common in North America.
Q: Can I eat elderberries raw? A: It's recommended to cook elderberries before eating them, as raw elderberries can be toxic. Cooking deactivates the harmful compounds, making them safe for syrups, jams, and pies.
Q: Is there such a thing as a naturally blue banana? A: Yes, the Blue Java banana is a real cultivar. It has a blue-silver peel when unripe and a creamy, vanilla-flavored flesh that gives it the nickname “ice cream banana”.
Q: Why are blue fruits so rare in nature? A: Blue is a less contrasting color than red or orange against green foliage, making it harder for animals to see and spread seeds. Some researchers also suggest a higher likelihood of red pigment production in plants.
Q: Are blue foods generally healthier? A: Blue and purple foods are typically rich in anthocyanins, powerful antioxidants associated with numerous health benefits, including supporting heart and brain health. So, adding more color to your diet, including blue, is a good idea.
Q: What vegetables are naturally blue? A: In addition to fruits, some vegetables are naturally blue or bluish. These include varieties of blue corn, blue potatoes (like the 'Adirondack Blue'), blue cabbage, and blue carrots.
Q: What about the blue honey controversy? A: In 2012, French beekeepers discovered blue and green honey. The bees had collected colored sugar from a nearby M&M factory, leading to the unnatural color. This was not a natural process and shows the impact of human waste on ecosystems.
Q: Can I use butterfly pea flower for blue food coloring? A: Yes, the butterfly pea flower is a popular natural blue food coloring, especially in Southeast Asia. It can be used to make tea or infused in liquids to create a natural blue hue.
Key Takeaways
- More Blue Fruits Exist: Beyond blueberries, fruits like bilberries, Damson plums, and Blue Java bananas are naturally blue or bluish.
- Color is Complex: The blue hue is often due to anthocyanin pigments, but in blueberries, it's a waxy outer layer scattering light.
- Bilberries Have Blue Flesh: Unlike the pale interior of typical blueberries, European bilberries have a rich, dark purple flesh.
- Blue Java Bananas are Real: This exotic variety is known for its pale blue skin and vanilla-like flavor.
- Blue Isn't Always Pigmented: Some foods, like blue corn and blue potatoes, also derive their color from natural pigments, expanding the 'blue' food category beyond just fruits.
- Adding Color to Your Diet is Healthy: Eating a variety of colorful fruits and vegetables, including blue ones, ensures a diverse intake of antioxidants and nutrients.
