Extract from The Telegraph:
A-Z of unusual ingredients: Konnyaku (By Rachel Smith)
Rachel Smith serves up exciting ingredients from all over the world. This week: konnyaku, the gelatinous Japanese substance now embraced as a miracle diet food.
Off the south west coast of Japan is an island which Chinese legend once referred to as "the land of happy immortals". Today, the "immortal" islanders living on Okinawa enjoy the longest life expectancy in the world. The population boasts a disproportionately high number of centenarians. And these aren't your standard centenarians. According to Dr Suzuki from The Okinawa Centenarian Study, they are also "youthful and energetic, and experience almost no cardiovascular disease or cancer".
So what is the secret? Many suggest genetics. But the Okinawa lifestyle - in particular the diet - is often cited as the main reason for the islanders' longevity. It is rich in vegetables, supplemented with a small amount of fish, and a selection of specialist ingredients. Amongst these, perhaps the most foreign - but also the most exciting to foreigners - is konnyaku, a gelatinous ingredient best known in the West as a miracle diet food.
Konnyaku is made from the pounded roots of a yam-like plant called konjac. The jelly-like ingredient has almost no calories, no sugar and no fat. It contains 90 per cent water. And much of the remaining 10 per cent is made up of glucomannan - a soluble fibre. Perhaps why, on the island of Okinawa, konnyaku is renowned for "cleaning the stomach".
From a sensory perspective, konnyaku is just as extraordinary as you would expect a pounded and processed root to be. It does not have a distinguishable taste. But it absorbs the flavours of liquid it is cooked in, meaning that it's most commonly simmered in a strongly-flavoured dashi or miso broth. It has a jellylike texture. To the touch, it is like an uncooked square of Rowntree's jelly. But a knife slides through a block of konnyaku with ease. The lack of resistance with a blade, or indeed in the mouth, more brings to mind a bouncy, gelatinous, cold pork stock.
Konnyaku is most commonly sold in block form. But there are several different varieties. Most popular in Britain are shirataki noodles - which are made from squeezing the konnyaku block into a more familiar spaghetti shape. Another variant is sashimi konnyaku. For this sashimi version, the konjac root is often processed with seaweed, sliced thinly and served raw - dressed only with a miso vinaigrette.
A traditional konnyaku serve is known as shimi konnyaku and was eaten by Japanese monks as part of their vegetarian diet. "To make shimi konnyaku, the konnyaku is frozen, and then defrosted so that most of the water is separated. Then the remaining konnyaku has a hard, spongy texture," explains Masaki Sugisaki, chef at Marylebone restaurant Dinings.
In Japan, dishes like shimi konnyaku are often regarded as stuck in the past. "Konnyaku used to be categorised as an old food, which was not popular," Sugisaki says. "But in the past few years, quite a few konnnyaku companies have developed new products - like konnyaku ramen, konnyaku pasta and sweet konnyaku jellies. It has been rebranded to appeal to younger generations in Japan, and it is now categorised as a healthy diet food."
It's not just in Japan where konnyaku is gaining popularity. Though still young on Britain's health food scene, konnyaku shows every sign of becoming a bigger and bigger player. Nutritional therapist Laura Lamont s potted a demand for imported shirataki noodles, and founded Zero Noodles - whose sales have quadrupled over the past year.
"Zero noodles are definitely an acquired taste, some people find the texture a little difficult to get used to," she admits. "But it seems that after giving them a few goes most people love them, they stick with them, as they're so low in calories as well as being gluten, sugar and fat-free. We now have a huge following of people in the UK who just canít get enough of them and swear that they are addicted."
So perhaps the cabbage diet will soon seem antiquated, and the konnyaku diet will become the modern version - ironically, based round an ancient Japanese ingredient.
Konnyaku in miso sauce
1 tsp dashi powder
1 tsp white miso
1/2 tsp dark soy sauce
1/4 pink daikon, peeled and cut into matchsticks
1 spring onion, sliced
1/2 tsp toasted sesame seeds
Remove the konnyaku from the package. Rinse under the cold tap. Blanche in boiling water for one minute, and then discard the water.
Cut the konnyaku into 2cm-thick rectangles. Use a knife to cut a small slit in the middle, and tuck the top of the rectangle through it, so that the konnyaku forms a twisted rope-shape.
Bring the water to a simmer in a pan. Stir in the dashi, white miso and konnyaku to the pan, and gently simmer for 6-10 minutes. Season with dark soy.
Arrange on a platter, and garnish with the daikon, spring onions and toasted sesame seeds. Serve as a side dish, or as a single portion, eaten with a bowl of rice.