| Amorphophallus rerieri is one of shade tolerance Perennial herb stem tubers, which belongs to Monocotyledoneae, Araceae. Konjac refined flour is a fine product made of fresh Amorphophallus rerieri stem tuber processed by drying, mechanical pulverizing and wind picking. Its main ingredient is Konjac Glucomannan (KGM), which is a macromolecule polysaccharide conjugated by D-glucose and D-Mannose residue with P-1,4 glucosidic bond. It has lots of unique characteristics such as rheological, thickening, gel formation and phragmoid character, so it is practical valuable in foodstuff, medicine and chemical engineering area.Content of KGM is a key index to judge the quality of Konjac refined flour. Studies at home and aboard demonstrate that KGM is a kind of excellent low calorie, low fat and high cellulose hydrosoluble food fiber, which has a veryimportant modulating effect on nutritious imbalance. It is helpful to the health of the people worldwide for its blood sugar lowering, blood lipid lowering, blood pressure lowering, fatty liver reversing, purging, body weight reducing, anti-cancer effects, immunological function enhancing and anti-consenescence effects.Nowadays, KGM is mainly extracted by 35 C water bathing and soaking Extraction, which needs longer time and gets lower extract rate, hence restricts the production and widespread application of KGM. Therefore, it is necessary to establish an efficient and easy method evaluating its quality. Ultrasonic wave shows its superiority in extraction of natural products in resent years. It can improve the extract effect by its mechanical function, thermotics function and powerful cavitation effect to accelerate intracellular material' s release, diffusion and dissolving. We investigate the extraction method for KGM by means of head ultrasonic instrument and water bathing ultrasonic instrument (ultrasonic wave washer), and compare them with conventional water extract method, respectively. The result shows the former can increase content of KGM in extract liquid by 10.81%, more than conventional water extract method (p<0.01), the optimal performance condition was fixed as follows: ultrasonic frequency 20kHz, power80W, 7min. The latter can increase content of KGM by 6.5% using fixedultrasonic frequency 40kHz, power 100W, Ih compared with conventional water extract method for 4h (p<0.001), These results demonstrated that ultrasonic wave water extract method could improve extract effect of KGM in Konjac refined flour. In the mean time, the methodology studies showed that the elegant precision, recycle rate, better linear relation and repeatability have been obtained. Nowadays, there are many methods to determine the content of KGM such as weighing method, spectrophotography, circumrotating viscosimetry, thin-layer chromatography and gas chromatography (GC). However, all these methods have their defects. For example, weighing method needs to be roasted many times even though it doesn't need expensive equipment, which is relatively tedious and may result in lower content because of incomplete deposition of mannohydrazone; thin-layer chromatography can get more nicety results, but it needs longer time to make board, in addition it also needs expensive thin-layer scaning densitometer; spectrophotography can also get precise results, but KGM and starch coexist in Konjac refined flour, when they are processed by acid, both of them can be dehydrated into glucose and mannose,leading to error of the experimental results; Gas chromatography has better repeatability and precision, and it can determine various monosaccharide's content of polysaccharide. The main problem is that saccharide itself doesn't have enough volatility, it must be transformed intovolatility derivative to be determined, precise condition, complex manipulation, longer time and expensive equipment must be needed.There are many reports concerned with determining plant's monosaccharide and polysaccharide by high performance liquid chromatography (HPLC), which has the characteri...
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