Parkia speciosa (petai, bitter bean, Thai: sataw (สะตอ), twisted cluster bean, yongchaa, yongchaak or kampai, zawngta (pronounced zongtra)or stink bean) is a plant of the genus Parkia in the family Fabaceae. It bears long, flat edible beans with bright green seeds the size and shape of plump almonds which have a rather peculiar smell, characterised by some as being similar to that added to methane gas.
The beans are an acquired taste, but are popular in Laos, southern Thailand, Burma, Malaysia, Singapore, Indonesia, and northeastern India, and are sold in bunches, still in the pod, or the seeds are sold in plastic bags. Pods are gathered from the wild, or from cultivated trees: they are exported in jars or cans, pickled in brine, or frozen.
Depending on the country of origin they may be labelled peteh, petai,yongchaa, yongchaak, Zawngṭa (pronounced Zongtra), sataw, or sator. They are best when combined with other strongly flavoured foods such as garlic, chile peppers, and dried shrimp, as in "sambal petai", or added to a Thai curry such as Thai Duck Green Curry. When young the pods are flat because the seeds have not yet developed, and they hang like a bunch of slightly twisted ribbons, pale green, almost translucent. At this stage they may be eaten raw, fried or pickled. Young tender pods with undeveloped beans can be used whole in stir-fried dishes. In Manipur, a north-eastern state of India, the seeds or the bean as a whole are eaten by preparing a local delicacy called Iromba or Yongchak singju. The Hmar tribe of northeastern parts of India call it Zawngṭa (pronounced Zongtra) and mainly prepare it with chilly peppers and a special fermented pork called "Sathu" and called it Zawngṭa-rawt. The seeds are also dried and seasoned for later consumption. When dried the seeds turn black. In Indonesia, petai is very popular in the highlands of Java, Sumatra, especially among Batak, Minangkabau and many other people in different cultures of the island.
Petai beans or seeds look like broad beans. Like mature broad beans, they may have to be peeled before cooking. Petai has earned its nickname 'stink bean' because its strong smell is very pervasive. It lingers in the mouth and body. Like asparagus, it contains certain amino acids that give a strong smell to one's urine, an effect that can be noticed up to two days after consumption. Like other beans, their complex carbohydrates can also cause strong-smelling flatulence.
The petai tree can grow to about 90 feet (30 metres). It bears flowers in a light-bulb shaped mass at the end of long stalks. The flowers secrete a nectar that attracts bats and other pollinators. The tiny flowers mature and die. Long, twisted, translucent pods emerge in a cluster of 7 or 8 pods. When those pods are mature, within them will reside the petai beans or seeds.