Winged beans

The winged bean (Psophocarpus tetragonolobus), also known as the Goa bean, four-angled bean, four-cornered bean, Manila bean, and dragon bean, is a tropical legume plant native to New Guinea. It grows abundantly in the hot, humid equatorial countries of South and Southeast Asia. In Southeast Asia and Papua New Guinea it is widely known, but only cultivated on a small scale. Winged bean is widely recognised by farmers and consumers in southern Asia for its variety of uses and disease resistance. Winged bean is nutrient-rich, and all parts of the plant are edible. Leaves can be eaten like spinach, flowers can be used in salads, tubers can be eaten raw or cooked, seeds can be used in similar ways as the soybean. The winged bean is an underutilised species but has the potential to become a major multi-use food crop in the tropics of Asia, Africa, and Latin America. The winged bean species belongs to the genus Psophocarpus, which is part of the legume family, Fabaceae. Species in the Psophocarpus genus are perennial herbs grown as annuals. Psophocarpus species have tuberous roots and pods with wings. They can climb by twining their stems around a support. The winged bean plant grows as a vine with climbing stems and leaves, 3–4 m (9.8–13.1 ft) in height. It is an herbaceous perennial, but can be grown as an annual. It is generally taller and notably larger than the common bean. The bean pod is typically 15–22 cm (6–8.5 in) long and has four wings with frilly edges running lengthwise. The skin is waxy and the flesh partially translucent in the young pods. When the pod is fully ripe, it turns an ash-brown color and splits open to release the seeds. The large flower is a pale blue. The beans themselves are similar to soybeans in both use and nutritional content (being 29.8% to 39% protein). The appearance of the winged bean varies abundantly. The shape of its leaves ranges from ovate to deltoid, ovate-lanceolate, lanceolate, and long lanceolate. The green tone of the leaves also varies. The stem, most commonly, is green, but sometimes boasts purple. The pods are usually rectangular, but sometimes appear flat. Pods may be coloured cream, green, pink, or purple. Pods may be smooth are appear smooth or rough, depending on the genotype. Seed shape is often round; oval and rectangular seeds also occur. Seeds may appear white, cream, dark tan, or brown, depending on growing and storage conditions. The entire winged bean plant is edible. The leaves, flowers, roots, and bean pods can be eaten raw or cooked; the pods are edible even when raw and unripe. The seeds are edible after cooking. Each of these parts contains vitamin A, vitamin C, calcium, and iron, among other nutrients. The tender pods, which are the most widely eaten part of the plant, are best when eaten before they exceed 2.5 cm (1.0 in) in length. They are ready for harvest within three months of planting. The flowers are used to colour rice and pastry. The young leaves can be picked and prepared as a leaf vegetable, similar to spinach. The nutrient-rich, tuberous roots have a nutty flavour. They are about 20% protein; winged bean roots have more protein than many other root vegetables. The leaves and flowers are also high in protein (10–15%).