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Scientific name Amorphophallus Amorphophallus rerieri, as Monocotyledoneae, shade tolerance Araceae perennial herb tubers. Amorphophallus konjac flour is made fresh tubers after drying, mechanical crushing, winnowing processes to get a fine product. Its main active ingredient of konjac glucomannan (Konjac Glucomannan, KGM, referred glucomannan). KGM is D-glucose and D-mannose residues by β-1, 4 glycosidic bond polymerization of polymer polysaccharides, it has a unique rheology, thickening, gelling and film in food , pharmaceutical, chemical, and so has a good application value. KGM KGM content is to evaluate the quality of a key indicator of domestic and foreign research confirmed, KGM is an excellent low-calorie, low-fat, high-fiber water-soluble dietary fiber, nutritional imbalance has an important regulatory role. Because of its ability to reduce blood sugar, blood fat, lowering blood pressure, reversing fatty liver, bowel weight loss, anti-cancer, enhance immune function and anti-aging medicine and health effects, which attracted worldwide attention. Currently, KGM use more flooding in 35 ℃ water bath extraction, extraction time is long, the extraction rate is low, limiting the scale of production of KGM and widely used. Therefore, it is necessary to establish a high extraction rate, easy way. In recent years, ultrasonic extraction of natural products has shown more and more advantage of using its mechanical properties, thermal properties and powerful cavitation, can accelerate the release of intracellular material, expanding the Fourth Military Medical University, Graduate Thesis a casual and dissolving, to improve extraction efficiency. Therefore, this type ultrasound probe and a bath-type ultrasound (ultrasonic cleaner) for KGM extraction was investigated experimentally, and separately with conventional water extraction were compared. The results showed that the former fixed ultrasonic frequency 20kHz, power 80W, the role of time 7min optimal operating conditions when the ultrasonic method than the conventional method extracts KGM content was increased \were fixed ultrasonic frequency 40kHZ, power 100W, ultrasonic water extraction lh, KGM content was significantly higher than conventional water extraction 4h (HO.001), increased 6.5%, indicating ultrasonic water extraction can improve the konjac flour in KGM extraction efficiency. methodological study was also carried out, the results show that the precision, good recovery; linearity and reproducibility is also good. KGM gravimetric measurement methods, spectrophotometry, rotate pea degree method, TLC , gas chromatography (GC). These methods are more or less different defects exist, although not require large gravimetric apparatus, but also more complicated, require multiple baking, and due to incomplete precipitation of mannose gland may cause measurement results is low; TLC, although more accurate measurement results, but the length of time the system board, and also requires more expensive TLC scanner; spectrophotometry results are more accurate, but konjac flour contains both KGM and starch with acid can be hydrolyzed to glucose and mannose, so will bring the error to the measurement results; gas chromatography are better reproducibility and accuracy, and to a variety of polysaccharides were measured monosaccharide content main difficulty is not in itself sufficient volatility carbohydrates must be converted to a volatile derivative and require high conditions is measured, the operation cumbersome, time consuming, and requires expensive equipment and high performance liquid chromatography (HPLC) determination plant polysaccharides and monosaccharides more coverage, it has a fast, convenient, high resolution, good separation, good reproducibility and does not destroy the sample, etc., especially suitable for the determination of certain sugars. HPLC determination of sugars compound, the sugar itself, no absorption in the ultraviolet region, the use of a differential refractive index detector gate I) test, but its low detection sensitivity and can not be used for gradient elution by the saccharide compound derivative into a material with UV absorption or fluorescence , is to improve the sensitivity of carbohydrate primary means by HPLC. HPLC measurement sample in the analytical column with sugar monosaccharides and amino bonded phase column, but its price is high, the high cost of analysis, in particular sugar analysis specific column. this paper KGM with sulfuric acid hydrolysis into glucose and mannose to match BU phenyl-3 - A 3 Fourth Military Medical University, Graduate Thesis a base - BU adjoin wow commanded ketone (PMP) after derivatization, the choice of lower prices C;. silica gel column for HPLC analysis KGM content and composition. Chromatographic conditions: ZORBAX Extend-C; s analytical column, 250 urn UV detection, different concentrations of acetonitrile and phosphate buffer gradient flow rate of 1.0 mL · min ', time 30 min. measurement taking different volumes of a mixture of glucose, mannose standard (plus internal standard rhamnose), dried under vacuum at room temperature, and a series of derivatized with PMP after centrifugation, 10 p L and the supernatant analyzed by HPLC. monosaccharide derivatives of standard and internal standard peak area peak area ratio of Y, the standard amount of a monosaccharide (nmol) of X plotted as the standard curve, the correlation coefficient r greater than 0.999, the same volume of glucose, mannose product was derivatized sample 5 times, glucose, mannose, rhamnose injection precision (RSD, n = 5) were 0.25% and 0. 09%, 0.52%. different volumes of glucose, rhamnose, mannose and derivatives thereof precision injection were 1.29%, 0.65%, 1.19% The results showed that, KGM from glucose and mannose, H by molar ratio of 1:1.67, konjac flour in KGM content of 79.54%. visible, HPLC simultaneous determination of KGM content and determine its composition. The results showed that ultrasonic extraction time can be shortened KGM, proposed rate increase, and the precision, recovery, reproducibility and linearity are good. After exploration we choose lower-priced C; s silica gel, step gradient elution , 250 urn UV detection, through the optimum operating conditions, 30 min separation and determination of three kinds of monosaccharides, for the determination of monosaccharides KGM obtained satisfactory results can be used to evaluate the quality of konjac flour.
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