The butterfly pea flower is a vibrant botanical specimen capturing attention, primarily for its striking, deep indigo hue. Known scientifically as Clitoria ternatea, this flower has transitioned from a traditional agricultural staple in Southeast Asia to a highly sought-after ingredient in Western beverages and foods. Its popularity is driven by its ability to impart a visually dramatic color to any liquid or dish. The flower offers a natural alternative to synthetic food colorings, making it a favorite for those seeking natural, plant-based ingredients.
Botanical Identity and Origin
The butterfly pea flower, Clitoria ternatea, is a perennial herbaceous vine belonging to the Fabaceae family (the pea family). This vigorous climber is native to the humid lowlands of tropical Asia, particularly India, Thailand, and the Indonesian island of Ternate. The plant produces distinctive, pea-shaped flowers that are typically a vivid deep blue with a splash of yellow in the center. For commercial use, the flowers are harvested and dried, allowing them to be steeped in hot water to release their intense color.
The Unique Color-Changing Property
The flower’s most fascinating characteristic is its ability to change color when exposed to different pH levels. This phenomenon is due to the high concentration of anthocyanins, water-soluble pigments found in the petals, specifically a group called ternatins. When steeped in neutral or slightly alkaline water (pH 6.0 to 8.0), these compounds display a brilliant, saturated blue color.
The color shift occurs when an acid, such as lemon or lime juice, is introduced, which lowers the pH value. The change in acidity causes a structural shift in the anthocyanins, moving from the quinoidal base form (blue) to the flavylium cation form (red/pink). As the pH drops, the color dramatically transitions from deep blue to purple, violet, and eventually pink or red in highly acidic environments (below pH 3.2). This acid-base indicator property makes the extract a natural colorimetric indicator, creating a striking visual effect in culinary preparations.
Common Culinary and Beverage Applications
The primary use of the butterfly pea flower today is as a natural food and beverage colorant, valued because its extract has a neutral or mildly earthy flavor. In Southeast Asia, particularly Malaysia and Thailand, it has a long history as a dye in traditional cooking. For example, the Malaysian rice dish Nasi Kerabu is infused with the flower extract to achieve a distinctive blue color.
The dried flowers are steeped to create a herbal infusion known as Blue Tea or Anchan Tea. This caffeine-free beverage is consumed hot or cold, often with honey or sugar. In modern mixology, the color-changing property is exploited to create visually stunning cocktails and mocktails. Bartenders use the deep blue liquid as a base, then add citrus to transform the drink into a lively purple or pink, providing a dramatic, interactive element.
Traditional Uses and Health Claims
For centuries, the butterfly pea flower has been a component of traditional medicine systems, including Ayurveda in India and various practices across Southeast Asia. Historically, it was used to address issues like stress and anxiety and was valued for its memory-enhancing and cognitive benefits. The flower is recognized as a source of various bioactive compounds, including flavonoids and anthocyanins, which contribute to its antioxidant capacity.
Modern analysis confirms the presence of these powerful antioxidant compounds, which protect cells from oxidative stress. Some studies suggest potential benefits such as anti-inflammatory effects and support for skin and hair health. However, many of these contemporary health claims are currently supported mainly by test-tube and animal studies. Extensive human clinical trial data is still needed to fully substantiate the flower’s therapeutic efficacy and determine appropriate dosages.