Purple lettuce refers to a vibrant group of leafy greens that bring striking visual appeal to salads and other dishes. These colorful varieties are recognized for their distinct hues, ranging from deep burgundy to reddish-purple, offering a noticeable contrast to their green counterparts.
What “Purple Lettuce” Means
The term “purple lettuce” is a descriptive classification rather than a singular botanical species. It serves as an umbrella term for several cultivars of Lactuca sativa, common garden lettuce, that display shades of red or purple. “Purple lettuce” and “red lettuce” are often used interchangeably, highlighting the broad spectrum of reddish-purple tones. This coloration is a natural genetic trait.
Common Purple Lettuce Varieties
Many specific varieties fall under the “purple lettuce” designation, each with unique characteristics:
Red Leaf: A widely recognized type, known for its loose, crinkled leaves that range from reddish-bronze to a deep purple, often with greener bases.
Lollo Rosso: A popular choice featuring highly frilled, curly leaves that are green at the center and transition to a vibrant reddish-purple at the edges. Its texture is typically crisp, adding a pleasant bite to salads.
Red Romaine: Offers a robust option, with elongated, upright leaves exhibiting a reddish-purple tint, particularly along the margins, while maintaining the crisp, slightly bitter flavor typical of Romaine varieties.
Red Sails: A classic leaf lettuce variety, identifiable by its frilly leaves in a deep reddish-purple color, which tend to be tender.
Merlot: Named for its wine-like color, producing large, deep red leaves suitable for both baby leaf and mature harvest.
Sea of Red: A cutting lettuce with narrow, lance-shaped purple leaves.
Red Deer Tongue: An heirloom variety producing sturdy, long, deep purple leaves.
Ruby Red: Noted for its dramatic deep color, often appearing best when combined with tender green lettuce.
Radicchio: While often grouped with purple lettuces, it is botanically a chicory or endive, distinguished by its firm, bright purple leaves with white stems and a notably bitter flavor.
Why Lettuce Turns Purple
The vibrant purple coloration in these lettuce varieties is primarily due to the presence of anthocyanins. These water-soluble pigments, a type of flavonoid, are responsible for the red, purple, and blue hues observed in many fruits and vegetables. Their concentration and environmental factors like light exposure, temperature, and pH levels in the plant’s tissues determine the color’s intensity. Anthocyanins also protect the plant from environmental stressors like excessive sunlight.
Flavor and Nutrition
Purple lettuce varieties generally offer a slightly different taste experience compared to their green counterparts, often described as more robust, earthy, or subtly peppery. Some sources note a slight bitterness, which can add complexity to dishes. Beyond their visual appeal and distinct flavor, purple lettuces are recognized for their nutritional content. They are a source of vitamins A, C, and K, and folate. The anthocyanins that give these lettuces their characteristic color also provide antioxidant properties. These compounds contribute to the overall nutritional value, making purple lettuce a beneficial addition to a balanced diet.