| "Medicinal gold" of Dioscorea, also known as yellow ginger, Yam root and so on, because of its unique biological activity such as anti-inflammatory, antibacterial, antiviral and other features, has always been the great attention by people. Our country is a resource-rich countries of Dioscorea. The investigation found that in our country, contains dioscin of Dioscorea, wearing main plant of Dioscorea nipponica, panthaica and so. Among them, contained in some of dioscin of Dioscorea most, about 2.5%, among them with Shaanxi Ankang, Shiquan area distribution of sapogenin content of Dioscorea high, this study provides a great convenience for us. This article to dioscorea as raw material, Selection of characteristic of the Shaanxi dioscorea plant, to yield of crude saponins as indicators in an existing ultrasonic extraction form factors, on the basis of single-level, ultrasound used in combination with circulation, using methods of ultrasonic extraction-circulation, the extraction and separation of total saponin of Dioscorea experimental study on the single factor; And under the same conditions, and compared using ultrasonic extraction only; Using response surface methodology (RSM) optimizing the extraction technological conditions of single factor; And then, on that basis, using atomic force microscopy and infrared spectroscopy instrumentation, from different perspectives to examine the effects of extraction by ultrasonic-circulation effect; Last CFD-computational fluid dynamics software to analyze the application of ultrasonic-circulation flow situations, investigation by numerical simulation speed, pressure, turbulent kinetic energy distribution in reactor; further validation of the feasibility of the method.This experiment is in working shown below:1.Uses the ultrasonic-loop reactor, according to the controlled variable method to study the ethanol concentration, solid-liquid ratio, ventilation, ultrasound time single factors such as ultrasonic frequency, ultrasonic power extraction from dioscorea effect of total saponins of crude extracts in; and on this basis, and comparison with ultrasonic extraction only; and optimizing extracting conditions of single-factor by RSM. Results indicate that for 1200ml ethanol solution, when the alcohol concentration is 70%, liquid-solid than 1:20, ventilation 0.6L/min, ultrasound time 10 min, ultrasonic power 70W, ultrasonic frequency 20 kHz. Average rate of extraction of ultrasonic-circulation is 5.99%, and only compared to the average extraction by ultrasonic extraction rate of 4.47%, extraction rate increase 25.38%.2. By atomic force microscope (AFM), environmental scanning electron microscope (ESEM) and thermal analysis instruments (TAI), Fourier infrared spectroscopy instrument (FISAI), analysis of effect of ultrasonic-circulation effect on plant cells. Analysis results indicates that:a). From the structure, by AFM figure can see, when the density is 10-3 mol/L, soap glycoside molecular formation uniform of molecular gathered, fragment structure; pictures size about for 5.00x5.00 nm, height about for 18.33 nm, entire regional within of rough uniform, molecular rendering mutual distorted structure; Dang concentration increased to 10-4 mol/L, the soap glycoside molecular mutual role formation tablets layer and fragment coexistence of structure; pictures of size about for 5.00×5.00nm, height for 29.10 nm. By ESEM figure observation to:Using ultrasonic vibration and cavitation effects, rapid movement of circulating liquids, speeding up the blending between solid-liquid interface, crushing the plant cell wall, causing rapid precipitation of effective components; Residue after extraction is rich in large amounts of cellulose, lignin and other fragments of insoluble components, indicates that the active ingredient in saponins have been isolated from its wrapper; Residue after extraction is not involved in the back of the experiment, reducing the resistance of the extraction of its constituents, illustrate the effect of ultrasonic-circulation is very good.b). Look from the composition, use of infrared spectrum and thermal analysis, detection and analysis on components of the extracted substances, experimental results show that:for the main substances in dioscorea-starch and cellulose, after ultrasound-circulation effect, its molecular arrangement and location changed, links between the two is interrupted, cellulose is not connected in a bundle of State around the starch grains, but with a fracture of the sheet around the absorption of starch granules in individual; making active ingredient ginsenoside easier is extracted from its wrapper; Large amounts of precipitation of lignin, also shows in dioscorea molecules of sugar chains are broken, after the starch hydrolysis occurs, precipitation of active ingredients, void component separated out, does not participate in the extraction and purification of behind the experiment.3. CFD-computational fluid dynamics software to analyze the application of ultrasonic-circulation flow situations, investigation by numerical simulation speed, pressure, turbulent kinetic energy distribution in reactor. Simulation shows:In the loop reactor size certain circumstances, change different entry gas velocity, the corresponding pressure, turbulent kinetic energy etc also changed; When inlet velocity reach when lm/s liquid flow velocity and pressure value, turbulent kinetic energy etc. Are all to achieve optimal value, explain this loop reactor internal flow field distributions, combine the best situation) to determine inlet velocity joined ultrasound for 0.5 m/s for optimal value. |
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