Amorphophallus Konjac glucomannan

Konjac mannan (Glucomannan) Araceae Amorphophallus konjac Koch Der Marderosian and Beutler (2002)... 

Values of K, for D-mannanase have been reported for the Bacillus subtilis83 enzyme (2.8 mg/ml for coffee-bean galactomannan, 5.9 mg/ml for soybean galactomannan, and- 3.4 mg/ml for konjac gluco-mannan), and the Amorphophallus konjac110 enzyme (714 /xg/ml for konjac glucomannan of M.W. 1.12 X 10 ). 

Konjac flour is a glucomannan obtained from the tuber of Amorphophallus konjac grown in Asia. The polysaccharide chain is... 

Konnyaku flour obtained from plant cultivars of Amorphophallus konjac K. Koch is an important food material because of its remarkable gelling properties at very low solids concentrations in water (less than 0.5%). It has been employed in certain regions of Asia, such as Japan, to make a variety of foods that were claimed to have significant health benefits. Glucomannan polysaccharides (GP) are the main active component of Konnyaku flour, and can... 

Konnyaku flour was obtained from tubers of plant cultivars of Amorphophallus konjac K. Koch that were kindly provided by Ajinomoto Co. Glucomannan polysaccharides were extracted from konnyaku flour and further purified from precipitates in ethanolic mixtures. The range of glucomannan oligosaccharides that are obtained by partial hydrolysis of GP is illustrated in Table I. 

Gelling mechanisms of glucomannan polysaccharides (GP) extracted from konnyaku flour obtained from plant cultivars of Amorphophallus konjac K. Koch... 

C,8H320,6 504.441 Isol. from the hydrolysates of konjac glucomaimaii (Amorphophallus konjac), mucous polysaccharides of Bletilla striata and the glucomannan in the tubers of Arum maculatum. Isol. from Asparagus officinalis seeds... 

A commercial glucomannan extracted from Amorphophallus Konjac was also tested. 

Figure 9. The relative elastic modulus of glucomannan from Amorphophallus Konjac at 50°C and birch xylan at 60°C as a function of relative humidity at a load frequency of 1 Hz, in humidity scans of 0.1 %RH/min.

For the glucomannan extracted from Amorphophallus Konjac, the modulus curves at 50°C at a load frequency of 1 Hz and a humidity rate of 0.1 %RH/min is compared to that of xylan in Figure 9. As in the xylan, a weak transition occurred at low relative humidity and a glass transition at 60 to 70 %RH. Also, for the glucomannan the transitions shifted to lower relative humidities with increasing temperature. 

The only commercially important glucomannan is konjak gum also known as konjak mannan. Konjak flour is obtained from the starchy tubers of the plant Amorphophallus konjac (Araceae), grown in subtropical to tropical eastern Asia (Japan, China and Indonesia). 

Polysaccharides have been isolated which contain both D-glucose and D-mannose, for example, the glucomannan of Amorphophallus konjacJ From this Konjac mannan ([a] o —42.8°) has been isolated a disaccharide composed of D-glucose and D-mannose units. The polysaccharide from the corms of Amorphophallus oncophyllus is a fibrous substance which contains 49 % of anhydroglucose, 41 % of anhydromannose, and 4 % of uronic anhydride, and yields 2 % of pentosans. This substance is an excellent beater additive when used in paper manufacture. 

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