Purple lettuce is a common sight in grocery stores and restaurants, offering a colorful alternative to green varieties. Its vibrant leaves add visual appeal and a unique texture to salads, sandwiches, and wraps. This appearance also signals a different nutritional profile compared to its green counterparts.
The Source of the Purple Color
The reddish-purple color of certain lettuce varieties comes from water-soluble pigments called anthocyanins. These are the same compounds responsible for the deep colors of many fruits and vegetables, such as blueberries and red cabbage. Anthocyanins are a type of flavonoid that function as antioxidants.
These compounds serve a purpose for the plant, helping to absorb excess light that could otherwise cause damage. The intensity of the purple color is influenced by environmental factors like light and temperature, and the colors are more pronounced when grown under bright light.
The presence of anthocyanins is significant because of their antioxidant properties, which help the body combat oxidative stress. Diets rich in anthocyanins are associated with health benefits, including supporting cardiovascular and eye health.
Types of Purple Lettuce
Consumers are likely to encounter several different types of purple lettuce:
- Radicchio: While technically a member of the chicory family, it is used like lettuce. It has a tight, round head of deep purple leaves with white veins and is known for its distinctly bitter taste.
- Lollo Rosso: This Italian lettuce is characterized by its loose, frilly leaves with a deep red or purple hue at the edges. It has a tender texture and a slightly more assertive flavor than many green lettuces.
- Red Oak Leaf: This lettuce gets its name from its lobed leaves that resemble an oak tree. The leaves are green at the base and transition to a deep red or purple at the margins, with a buttery texture and a mellow, nutty flavor.
- Red Romaine: A purple-hued version of a classic, its outer leaves boast a reddish-purple color while inner leaves might be lighter. It maintains the characteristic crunch of green romaine and can be used in Caesar salads or on sandwiches.
Flavor Profile and How to Use It
The flavor of purple lettuces can differ from the mildness of green varieties like iceberg. Many purple types, particularly those in the chicory family like radicchio, have a noticeably bitter or peppery taste that adds complexity to dishes.
In salads, it provides a contrast in both color and taste when mixed with milder greens. The sturdy leaves of varieties like Red Romaine and radicchio can also be used as a wrap for fillings. Some heartier types, such as radicchio, can be grilled or roasted, which mellows their bitterness and brings out a subtle sweetness.