| At present, isoflavone becomes one of the most remarkable functional components. Researchs on its extraction and antioxidizability catch the notice of all over the world. The study focuses on finding the most economical way to extract and purify the high quality isoflavone.The qualitative identification by chemical and spectroscopic method, we can verify that there is isoflavone in the extract. At the same time, we compare three quantitative methods, which are sigle-wavelength, three-wavelength, and HPLC.When the starting material for the inventive process is the defatted soybean flakes, thinking of the higher distilling rate, easy to reclaim, no side-effect, we select aqueous ethanol as distilling solvent. When the distilling rate is the first target, the best condition was 80% aqueous alcohol, 25:1 as the ratio of solvent to the defatted flakes, at 60 ℃ , 9 hours (the distilling rate is 92.6%). If we consider of the economic benefit, then the ratio of solvent to the defatted flakes should be decreased to 20:l(the distilling rate is 91.8%). After pre-processing the defatted flakes with microwave, we find that after radiating it 4min by microwave, the dissolving rate of isoflavone and isoflavone's purity increase, and the ratio of solvent to the defatted flakes decrease to 15:1.We extract the lipid with hexane and then compare the removing effect of 20% trichoroacetic acid and 2.0mol/L chlorhydric acid after having condensed the extract. The result indicates that chlorhydric acid is the better one. Next, the condensate is treated with an adsorptive resin to get purify further. Comparing the capabilities of three resins, we choose the XAD-4 as the resin of purification. According to the One-factor analysis, we get the appropriate operation condition of adding the condensate to the resin as flowing at the speed of 2BV/h at 40℃ , and the best adding volume is 1.58 liters per liter resin. Then eluting it with water to remove the aqueous impurity at 25 ℃ . At last, the isoflavone is eluted with gradient aqueous alcohol. There, when we think the reclaiming rate of isoflavone is the most important, we use regression to analysis the effect of the eluting temperature and the velocity of eluting flow on the reclaiming rate, the equation is y=19.8802+2.4854x, ?0.02029xi2. And according to the equation, we get the best eluting condition as flowing at the speed of 1.04BV/h at 60 ℃ , and the reclaiming rate of isoflavone is 97.10 + 1.2%.Then, condensing the eluting solution until it become solid. And determining the purity of the solid, the result is 56.43%. On the other hand, when we think the separating rate of isoflavone is the most important, we elute the resin with discontinuous gradient aqueous alcohol to separate differentisoflavone fractions just when purifying them.When the starting material for the inventive process is soy whey, we remove protein from it by microwave operation at first. The operation can rid 66.12+1.46% protein of the soy whey. But at the same time, 5.95+0.94% isoflavone is lost. Then putting this soy whey through a resin adsorption process to separate isoflavone. The best adding volume of soy whey is 4.10 liters per liter resin, in which the concentration of isoflavone is 40.92mg/L. Then eluting it with 20% aqueous alcohol to remove the impurity at 25 ℃ . At last, the isoflavone is eluted with gradient aqueous alcohol which flowing at the speed of 1.04BV/h at 60 ℃ . Here, the reclaiming rate of isoflavone is 96.81%.On the basis of different demand of the product, we can decolour and recrystallize the resulting isoflavone. The best condition of decolouring is putting 15g/L active carbon to the concentrated eluting solution, this operation should retain 10 min at 80 ℃ .In order to recrystallize, we add ice -block to the acetone solution of isoflavone, which has equal volume to acetone, then putting the solution into refrigerator all the night. The purity of the product after recrystallizing becomes 91.3%, but then the reclaiming rate of isoflavone is down to 19.6%.At last... |
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