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Konnyaku: Gunma's Superfood

Discover the health benefits of konnyaku, an international superfood grown in Gunma

Konnyaku: Gunma's Superfood

Last updated: March 03, 2023

Gunma is Japan’s leading producer of konnyaku (konjac), a food that is valued for its versatility and health benefits. High in dietary fiber and low in calories, konnyaku is gaining popularity around the world as a versatile, vegan ingredient that can add fiber and texture to many dishes.

Konnyaku is derived from the potato-like corm (bulb) of the konjac plant (Amorphophallus konjac) which is sometimes called devil’s tongue for its distinctive purple lilies. The corm contains glucomannan, a form of soluble fiber which has been shown to lower blood cholesterol and glucose levels and is similar to the soluble fiber found in oats, apples and psyllium. Konnyaku is made by mixing konjac flour with water and an alkaline coagulant. Without other additives, konnyaku is white, but hijiki and kajime seaweeds are often added for color.

Health benefits

The key ingredient of konnyaku is glucomannan, a form of soluble fiber. This fiber helps to block cholesterol absorption in the small intestine and slows the absorption of glucose, helping to lower blood sugar levels. Soluble fiber also aids digestion. Western diets are commonly low in fiber, so foods like konnyaku can be incorporated to help reduce the risks of heart disease and diabetes.
Konnyaku is also high in calcium, which can promote bone strength. Common sources of calcium such as dairy foods and small fish are unsuitable for vegetarians, so konnyaku is said to be a good alternative.

With more international focus on the health benefits of traditional Japanese foods such as matcha, miso, natto and tofu, konnyaku is becoming popular overseas as a “superfood”, for being low in calories and high in fiber.

A versatile ingredient

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Konjac flour has no flavor, but when mixed with water and an alkaline coagulant, it takes on a firm, jelly-like texture. It can be formed into noodles and thin, sashimi-like slices, or even grilled like a steak. The versatile ingredient can be sweetened to create jelly desserts and snacks, added to hotpots for a satisfying texture, or grilled and served with savory flavors like miso. The flour can also be used in cakes and snacks.

Unlike gelatin and agar-agar, konnyaku does not break down in hot liquids, making it an ideal ingredient in soups and stews. Many popular winter dishes in Japan feature konnyaku, including oden. Konnyaku, daikon, and other ingredients are stewed in dashi broth. Shirataki noodles made of konnyaku take on the flavor of other ingredients and add a satisfying texture to beef dishes such as sukiyaki and gyudon.

Many classic Gunma dishes feature konnyaku. Try miso dengaku konnyaku, a block of boiled konnyaku served with a delicious sweet and salty miso sauce, which is a popular snack in many onsen towns. Don’t miss Ishidan Tama Konnyaku in Ikaho Onsen—skewers of konnyaku balls steeped in a special soy sauce and topped with a dab of hot mustard. These snacks are easy to prepare, and visitors to Konnyaku Park can buy a range of easy-to-cook konnyaku dishes to take home.

Konnyaku’s jelly-like texture makes it a natural choice for sweets. You can find konnyaku jellies and chewy gummies, and even cakes and cookies made with konnyaku, giving a natural fiber boost to sweets and snacks.

How to get to Ikaho

New tastes and innovations

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Nowadays, many chefs and producers are devising new ways to enjoy konnyaku, driven by the growing interest in konnyaku as a versatile health food. Around 90 percent of Japan’s konjac plants are grown in Gunma, and the prefecture is leading the way in natural and tasty new ways to eat konnyaku. Some konnyaku producers are partnering with local fruit orchards to produce eco-friendly konnyaku fruit jellies from the seasonal harvest. With innovative packaging ideas such as drinkable jelly pouches and natural ingredients including local spring water, these new products appeal to health-conscious consumers.

At hotels and cafes, and at farmers markets and roadside stations across Gunma, you can try attractive sweets such as parfaits and soft serve ice creams featuring konnyaku. Growing awareness of conditions like gluten intolerance has led to the development of cakes and sweets using konjac flour, as a gluten-free alternative.

Explore and experience konnyaku

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Visit Konnyaku Park to learn more about this versatile ingredient. On weekdays you can tour the factory to see the production lines of konnyaku, shirataki noodles and sweet jelly. Try a wide variety of konnyaku dishes at the free buffet, open every day. Learn how to make different types of konnyaku including fruit jelly, at the onsite kitchen (advance reservation is required). Children and adults can enjoy the colorful playground and ferris wheel, along with a shrine to konnyaku, called Undama-jinja Shrine. You can also buy every kind of konnyaku to take home, from sweets and snacks to savory dishes.


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