Japan (Tochigi, Gunma, and Fukushima prefectures as major konjac production regions; ancient processing tradition)
Konnyaku (蒟蒻, konjac jelly) is a firm, gelatinous food made from the starch of the konjac plant (Amorphophallus konjac), which grows in Japan and East Asia. The tuber produces a glucomannan starch that, when mixed with water and an alkaline coagulant (calcium hydroxide — slaked lime), forms a firm, rubbery gel with an extraordinary property: it is almost entirely indigestible dietary fibre with effectively zero calories. Konnyaku is produced as blocks (ita konnyaku — flat slabs) or as noodle-like strings (shirataki — 'white waterfall'). The distinctive alkaline, slightly fishy aroma of konnyaku is a result of the calcium hydroxide coagulation process and can be reduced by parboiling before use. Konnyaku absorbs flavours remarkably well during simmering — though it never completely loses its firm, bouncy, slightly chewy texture (the texture Japanese call 'puyo-puyo'). It is used in oden (hot pot stew), sukiyaki, niku jaga, dengaku (miso-glazed), and as an addition to various nimono. Black konnyaku (kuro konnyaku) is made with nori or hijiki seaweed incorporated, producing a dark colour and slight marine flavour. The health food boom has positioned konnyaku as Japan's original 'zero calorie' food.
Almost neutral with a slight alkaline note; absorbs surrounding flavours; the texture — firm, elastic, slightly bouncy — is the primary sensory contribution
{"Konjac glucomannan: almost entirely indigestible fibre; zero effective calories after digestion","Alkaline coagulation: calcium hydroxide sets the glucomannan gel; produces the alkaline flavour note","Parboil before use: reduces alkaline taste and impurities; standard practice before incorporating into dishes","Flavour absorption: konnyaku absorbs braising liquid flavour over extended simmering — it improves in stews","Puyo-puyo texture: the elastic, slightly bouncy chew is the textural value; it cannot be softened away"}
{"Score the surface with crosshatch cuts before simmering — increases surface area for faster flavour absorption","Tear konnyaku by hand rather than cutting — the irregular torn surface absorbs more flavour than clean cuts","Karashi mustard is the traditional accompaniment for plain boiled konnyaku — miso dengaku is the other classic","Shirataki noodles are excellent in niku jaga and sukiyaki; they absorb the sweet-soy broth better than any other noodle"}
{"Skipping the parboil — the alkaline flavour overpowers the dish if not reduced first","Under-simmering in braised dishes — konnyaku needs extended cooking time to absorb flavours","Expecting it to taste of its surroundings without adequate cooking time — it is a long-simmering ingredient","Serving cold — konnyaku's texture is best warm or room temperature; cold makes it more rubber-like"}
Tsuji Shizuo, Japanese Cooking: A Simple Art