Hyacinth Bean, Vaal Bean, Lablab

Lablab purpureus

Family: Fabaceae | Place of Origin: Tropical Asia and Africa 

Origins and history:   

This legume originated in tropical Asia and Africa and was cultivated in India as early as 2500 BC.² It spread through colonization to Central and South America, and is now cultivated worldwide, mostly in tropical and subtropical regions. As it is a legume, it has a high protein content and is grown as a nutritious food crop for human consumption as well as animal fodder. It is an important food product in India and, is growing in popularity in Africa. Hyacinth Bean grows well in dry conditions, and is also a major forage crop for livestock, especially in Australia. Intercropping Lablab with maize has been shown to increase crop yields while preventing erosion and providing fodder for livestock. Its drought resistance may make it an even more important crop as climate change advances. In the United States and Europe, it is grown mostly as an ornamental vine instead of a food crop.  

Identification characteristics  

• Habit: Herbaceous climbing annual vine that can grow up to 6 meters in length. It does best with trellising for support. 
• Leaves and Stem: The leaves are alternate trifoliate with ovate-triangular leaflets measuring 7-15 cm long. The top side of the leaf is a deep green and smooth, while the underside is tinted purple, and is hairy. The stem can be somewhat hairy or smooth.
• Inflorescence: The flower sprays resemble sweet peas, range from purple to pink to white in color, and are slightly fragrant.    
• Fruits and Seeds: The pods can grow up to 14 cm long, may be straight or curved, and are a glossy purple or green. Seeds are oblong, and can be white, reddish-brown, or black.

Uses and preparation

• Much of this plant can be eaten if it is prepared correctly. Young leaves and flowers can be cooked and eaten like spinach, and young, immature pods can also be cooked. Purple pods lose their vivid color when cooked, turning a pale green.  
• Mature, dried beans need to be soaked overnight, then cooked in at least two changes of water. This is because mature beans (especially the dark colored ones) contain cyanogenic glycoside, much like Lima beans, and need to be soaked and cooked in multiple changes of water to avoid cyanide poisoning. The beans and pods are often used in stir-fry dishes.
• Hyacinth Beans can be used much like soybeans. In Indonesia, the beans are fermented to make a type of tempeh. Beans can also be sprouted and then cooked. Hyacinth Beans (usually the white variety) can be purchased in the United States at Indian grocery stores under name Vaal Beans. 
• Kenyans traditionally use Lablab as a means to encourage lactation, so it is a popular food among breastfeeding mothers.