Blue is a rare and captivating color in the natural world, especially when it comes to food. Finding truly blue foods can feel like searching for treasure. While many foods we perceive as blue might lean towards purplish or greenish hues, there are indeed edible items that offer a touch of this elusive color. This article delves into the fascinating world of blue foods, exploring where this color comes from, and showcasing a variety of naturally blue ingredients you can incorporate into your diet.
Many blue foods owe their vibrant color to pigments called anthocyanins. These fascinating compounds are not just about aesthetics; they are also potent antioxidants. However, anthocyanins are sensitive to pH levels, meaning their color can shift depending on acidity or alkalinity. This explains why some “blue” foods might change color when cooked or combined with other ingredients. Let’s explore some of the most intriguing blue foods, categorized by their pigment source.
Blue Foods Colored by Anthocyanins
Blueberries
Blueberries are perhaps the most well-known blue fruit. When you pick them fresh, they boast a beautiful blue hue. However, when crushed or cooked, they often turn reddish-purple. This color shift is due to the anthocyanins in their skin reacting to the natural acidity of the berry. In neutral pH conditions, the pigment appears blue, but acidity pushes it towards red. Interestingly, blueberries can even turn greenish in highly alkaline environments, such as when mixed into pancake batter with too much baking soda. While their color is fascinating, the flavor of blueberries, enhanced by their natural acidity, is often the main attraction. To prevent unwanted green discoloration in baked goods, consider reducing baking soda or adding a touch of lemon juice or buttermilk to your recipe.
Blue Corn
Blue corn is another striking example of naturally blue food, thanks to its rich concentration of anthocyanins. The color of blue corn can vary based on pH. In acidic conditions, it tends towards purple, while in basic conditions, the blue color becomes more pronounced. Blue cornmeal is a versatile ingredient that can be used as a vibrant substitute for yellow cornmeal in dishes like cornbread and tortillas, adding both color and a slightly nutty flavor.
Red Cabbage (and its Blue Dye Potential)
Red cabbage, surprisingly, is a secret weapon for creating natural blue food coloring. While it appears purplish-red in its raw state, cooked red cabbage leaves can transform into a bluish-purple shade when soaked in a slightly alkaline solution. To make a blue food dye from red cabbage, simply slice the leaves and boil them in water for 10-15 minutes. Strain out the cabbage and reduce the remaining liquid until it thickens into a syrup. This syrup will initially be intensely purple. By adding tiny amounts of baking soda, you can gradually shift the color towards blue. It’s crucial to add baking soda sparingly to avoid affecting the taste negatively. This homemade blue dye can then be used to tint icings, cake batters, and cookies, adding a natural touch of blue to your culinary creations. However, remember that this dye is still pH-sensitive and might revert to purple in acidic foods.
Purple Potatoes
Purple potatoes are a visual delight. Their vibrant purple hue is striking when raw, and upon cooking, they transform into a beautiful blue-purple. Unlike the dramatic pH-driven color changes seen in red cabbage or blueberries, the color change in purple potatoes during cooking is due to a different chemical process. Cooked purple potatoes are less susceptible to acid-induced color changes, though strong acids can still cause them to fade to a lighter purple. They are also less prone to color bleeding, making them an excellent way to introduce unusual color to your plate without much hassle. Beyond their aesthetic appeal, purple potatoes are nutritionally superior to white and yellow potatoes, thanks to their high anthocyanin content. Try swapping them into your favorite potato recipes for a colorful and healthy twist.
Cornflowers
Cornflowers, also known as bachelor’s buttons, are naturally bright blue edible flowers. Their blossoms have a mild, grassy flavor and are primarily used for their striking color. Fresh cornflowers can be sprinkled on salads or used as an elegant garnish for desserts. Dried cornflowers also make a beautiful garnish. Some tea blends incorporate cornflowers for their visual appeal, creating a stunning contrast against dark tea leaves. When using edible flowers, always ensure they are from a reputable source and have been grown organically or treated with food-safe chemicals.
Borage
Borage is an Italian herb with distinctive blue, star-shaped flowers. Often grown near tomatoes and eggplant in gardens, borage plants feature large, textured leaves and clusters of small blue flowers. In traditional folk medicine, borage flowers are believed to have mood-boosting properties. Whether or not that’s true, adding these pretty blue flowers to your plate is sure to elevate the visual appeal of your meal. Use fresh borage flowers to garnish salads or desserts for a touch of color and a very subtle cucumber-like flavor.
Butterfly Blue Pea Flower
The butterfly blue pea flower is arguably the most visually stunning blue anthocyanin source in the culinary world. This pea vine produces intensely blue flowers that are widely used in Thai, Malaysian, Burmese, and Chinese cuisines. In Malaysian cooking, these flowers are used to create the blue speckles in Pulut Tai Tai, a coconut and pandan flavored sticky rice cake. They also lend their vibrant color to Chor Ladda, intricately shaped Thai dumplings that resemble bright blue flowers. In Thailand, butterfly pea flowers are used to make a refreshing chilled herbal tea. The flowers can be used fresh or dried to create a remarkably vibrant blue infusion. Dried butterfly blue pea flowers have a mild, herbal flavor with a hint of cucumber. One interesting characteristic of butterfly pea flower tea is its color-changing property: the electric blue infusion turns purple when acid, such as lemon juice, is added.
Other Sources of Blue Color in Food
While anthocyanins are the primary source of blue color in many plant-based foods, there are other, less common ways foods can acquire a blue hue.
Blue Cheese
Venturing beyond the plant kingdom, blue cheese gets its distinctive blue veins not from anthocyanins, but from mold. During the cheese-making process, specific types of mold cultures from the Penicillium genus are introduced. The exact mold species varies depending on the type of blue cheese. Yes, it’s related to penicillin, although eating blue cheese won’t cure infections! The blue color in blue cheese is typically quite dark and stable, not prone to color bleeding. For serving blue cheese in cold dishes, try using a cheese wire to create thin sheets. This showcases the beautiful mottled blue patterns within the cheese, making it more visually appealing than simple crumbles.
Pickled Garlic (Unexpected Blue!)
Pickled garlic can sometimes develop an unexpected blue or green hue. This isn’t due to mold, but rather a chemical reaction. When raw garlic is pickled, sulfur compounds in the garlic can react with trace amounts of copper present in water or cooking utensils. This reaction forms copper sulfate, which results in a blue-green discoloration. This color change can take a few weeks to appear after pickling. To prevent pickled garlic from turning blue, blanching the garlic briefly in boiling water before pickling can help. While the small amount of copper sulfate in discolored pickled garlic is harmless, it’s a reminder that copper sulfate in larger quantities is toxic.
Bluefoot and Blewit Mushrooms
Bluefoot and Blewit mushrooms are often described as blue, though their color leans more towards purple. Despite the slight misnomer in their name, they are undeniably beautiful and possess a unique, remarkable flavor. Bluefoot mushrooms are cultivated and available in specialty stores, though they are considered a rarer and more expensive variety. Blewit mushrooms are related but are wild mushrooms, making them harder to find commercially. Blewit mushrooms tend to be more uniformly blue-purple, while bluefoot mushrooms are typically blue primarily at the base of their stems. Bluefoot mushrooms have a rich, woody, and meaty flavor that intensifies when cooked, particularly when paired with cream-based sauces. Like other flavorful mushrooms, their taste beautifully permeates dishes, making them a gourmet addition to your culinary repertoire.
