Konjac (Amorphophallus konjac; syn. A. rivieri; Japanese: 蒟蒻/菎蒻; こんにゃく; konnyaku; Korean: 곤약; gonyak; ), also known as konjak, konjaku, devil's tongue, voodoo lily, snake palm, or elephant yam (though this name is also used for A. paeoniifolius), is a plant of the genus Amorphophallus. It is native to warm subtropical to tropical eastern Asia, from Japan and China south to Indonesia.
It is a perennial plant, growing from a large corm up to 25 cm in diameter. The single leaf is up to 1.3 m across, bipinnate, and divided into numerous leaflets. The flowers are produced on a spathe enclosed by a dark purple spadix up to 55 cm long.
In Japanese cuisine, konnyaku appears in dishes such as oden. It is typically mottled grey and firmer in consistency than most gelatins. It has very little taste; the common variety tastes vaguely like salt. It is valued more for its texture than flavor.
Japanese konnyaku jelly is made by mixing konnyaku flour with water and limewater. Hijiki is often added for the characteristic dark color and flavor. Without additives for color, konnyaku is pale white. It is then boiled and cooled to solidify. Konnyaku made in noodle form is called shirataki (see shirataki noodles) and used in foods such as sukiyaki and gyudon.
Japanese historical novelist Ryotaro Shiba claims in a 1982 travelogue that konjac is consumed in parts of Sichuan province; the corm is reportedly called moyu (魔芋), and the jelly is called moyu dofu (魔芋豆腐) or shue moyu (雪魔芋).
Konjac has almost no calories but is very high in fiber. Thus, it is often used as a diet food.
Perhaps due to several highly publicized deaths and near-deaths among children and eldery due to suffocation while eating konjac candy, there were FDA product warnings in 2001 and subsequent recalls in the U.S. and Canada. Unlike gelatine and some other commonly used gelling agents, Konjac fruit jelly does not melt on its own in the mouth. The products that were then on the market formed a gel strong enough such that only chewing, but not tongue pressure or breathing pressure, could disintegrate the gel. The products also had to be sucked out of the miniature cup in which they were served and were small enough such that an inexperienced child could occasionally accidentally inhale them. Konjac fruit jelly was subsequently also banned in the European Union.
Some konjac jelly snacks now on the market have had their size increased so that they cannot be swallowed whole. The snacks usually have warning labels advising parents to make sure that their children chew the jelly thoroughly before swallowing. Japan's largest manufacturer of konjac snacks, MannanLife, has stopped production of the jellies after it was revealed that 17 people have died from choking on konjac since 1995.