Technology And Fundamental Researches About New Process Of Diosgenin

The wastewater from diosgenin production is called as the king which is great acidity, thick colour, high organic matter concentration. At present, there isn't an appropriate process that can be used to treat the wastewater successfully in practical engineering. The diosgenin plants mainly lie the upriver of Danjiangkou Reservoir wich is the water source of the middle line of South-to-North water diversion project (MLSWDP). The water pollution will directly effect the water quality of the MLSWDP, and effect the national strategy. If no effective measures adopting, the diosgenin plants will face the fate of closed.In order to changing the situation of diosgenin, we put up the enzymatic hydrolysis method to comprehensive utilize the starch by fermenting fuel ethanol. We study the factors of the Dioscorea zingiberensis C. H. Wright pasting property, liquefaction and saccharification. The optimal operation conditions are achieved: the particle 0.28mm, add water by the rate of 5 (w/w), the amount ofα-amylase 10u/g, at 90℃holding 30min; And then, adjust pH 4.0～4.5, add the amount ofglucoamylase 60u/g, at 60℃holding 90min.We put forward a new treatment method——heat decomposed technology to improve the situation of diosgenin. Fundamental research is carried in order to provide the theory base. It can predigest the process and avoid the pollution. There is no acid, alkali reagent and wastewater in the whole process. What's the most important is no washing and no wastewater. So it is the real pollution-free technology. Now, we have applied the invention patent. It has been sponsored by the project of Henan Province Education office.We take the lead in researching the factors of heat-decomposed technics, get the process optimization and the mathematic mold by response method. The effect of heat decomposed is better with high pressure, long holding time, and moderate material amount. The best condition is the steam pressure 1.4 MPa, holding 30min, the material 3.5kg and the product rate 1.745%. The treated material was better with weak color when CO₂ added, but it's acidity was increased slightly, and the holding time needed longer.We obtain the correlation formula about the product rate and heat-decomposed factors by SAS software: Y^1.4=1.619992+0.445945^*X1+0.436486^*X2-0.128199^*X3-0.186137^*X1^*X1+0.180706^*X1^*X3-0.266779^*X2^*X2+0.155259^*X2^*X3, R²=0.9753.In this paper, we extract diosgenin from heat-decomposed material by solvent extraction, SFE-CO₂ by contrast with acid-hydrolyzed material. The factors of solvent extraction are investigated about extracting time, temperature, the amount of solvent and granularity. The heat decomposed material: product rate is 1.75%, extraction rate is about 72.9%; The acid hydrolyzed material: product rate is 10.5%, extraction rate is about 75%. The amount of diosgenin is higher from acid-hydrolyzed than from heat-decomposed material. But at the raw material point, their extraction rates are same.The response surface stereograms and contour plots in SFE-CO₂ extraction with heat decomposed material are gained by SAS software. According to the result of error analysis, the CO₂ flux is the most important, the pressure is the next, and then is the amount of material. The terms of optimization: the pressure 35 MPa, temperature 55℃, CO₂ flux 12 kg/h, the material 125g, and the extracting rate 89.96%.We obtain the correlation formula about the extracting rate and factors about heat decomposed material with SFE-CO₂ extraction by SAS software: Y=74.68667+7.478333^*X1+1.456667^*X2+8.560833^*X3-4.654167^*X4-1.08375^*X1^*X1+2.9625^*X1^*X2-2.205^*X1^*X3+3.5925^*X1^*X4+0.77125^*X2^*X2+1.9975^*X2^*X3-1.405^*X2^*X4-4.61^*X3^*X3-1.855^*X3^*X4-3.365^*X4^*X4, R²=0.9300.In SFE-CO₂ extraction process with the acid-hydrolyzed material, the pressure is the most important, the CO₂ flux is the next, and then is the temperature. The best terms obtained by Orthogonal test are the material 100g, time 4h, the pressure 35 MPa, temperature 45℃, CO₂ flux 12 kg/h, and ethanol 300mL, the extracting rate 88.25%.We discuss the mechanism, characteristic of original and the treated material by meanas of SEM, FT-IR, X-ray diffraction and thermal analysis. The change of amylum and cellulose in the tubers among the heat-decomposed process are discussed. The results show that heat-decomposed technology can break up the supermolecule structure of amylum and cellulose. Diosgenin can be directly extracted from the heat-decomposed material. The product extracting from the heat-decomposed material is identified as diosgenin by melting point, UV, FT-IR, ¹HNMR, UPLC-MS. The extracts from different material with different extraction methods are quantitated by UPLC-MS. The results show that the content of diosgenin extracting from acid-hydrolyzed residue is higher than that from heat decomposed material by solvent extraction. While the content from heat decomposed material is higher than that from acid-hydrolyzed residue by SFE-CO₂.The powder material is acid hydrolysis with circumfluence time 3～6h. There are a lot of wastewater produced in acid hydrolysis procedure. But, the material about 5cm is treated 30min in the heat decomposed method, and there is no wastewater in the whole process. Whatever the economy or environment protection, the heat decomposed method is more preponderance than acid hydrolysis. So, the heat decomposed technology is a simple method without acid-hydrolysis and no wastewater produced. It is a revolution of diosgenin and can solve the pollution problem root and branch. It is significant to improve the market competition capacity of diosgenin.