Research On The Extraction And Purity Of Proanthocyanidins From Fermented Grape Seeds

The properties, efficacy, and pharmacological effects of proanthocyanidins including the progress of the study at home and abroad are introduced in this thesis. The dissertation mainly studied the technology of extraction and separation from the fermented grape seed. The extraction conditions, separation method and separation conditions of proanthocyanidins from grape seeds can be obtained by experiment. The main work of the thesis and achievement are summed up as follows:1. Based on the previous results, the vanillin-hydrochloric acid method was founded for analyzing proanthocyanidins. Linear relation and the regression equation were maked between concentration and absorbance with the standard sample.2. In extraction process from the fermented grape, ethanol solvent was maily used in this paper, five extraction conditions were studied: the extraction times, extraction time, temperature, concentration of solvent and ratio of solid to liquid. The result showed that the optimum extration conditions were obtained as follows: concentration of ethanol at 60%, ratio of solid to liquid at 1:7, temperature at 58°C, extraction for 3 times and 30 minutes each time. The extraction yield is 1.58% with this method. In addition, mixed solvents of methyl alcohol, ethanol and acetone effect on the extraction rate was studied, the results showed that the extraction rate was 2.06% when the solvent proportion was 1:3:2, the extraction rate of the mixed solvents was 28.0% higher than that of single solvent.3. The optimal experiment conditions were achieved by orthogonal experiment: according to their significance, the descending sequence of above foactors was B(temperature) > D(extraction time) > C(alcohol volume fraction ) > A(the solid-liquid ratio). The optimization process conditions were A₂B₃C₁D₃, with the temperature of 60℃, from time to 40 min, alcohol volume fraction of 50% and the solid-liquid ratio at 1:7. And the better extraction rate can reach to 1.61%.4. Macroporous resin was used in the separation of procyanidins. After studying six macro porous adsorption resins with column chromatography, O3F3 resin was selected as the best adsorbent, the dynamic state adsorption properties and desorption properties of O3F3 resin were studied. Experiments results indicated as follows: O3F3 resin was an excellent adsorption resin. Under experiment conditions, the adsorption equilibrium time was 240min. The results indicated that adsorption isotherm was correlated with Langmuir-type equation. The optimum conditions of dynamic adsotption were that concentration of proanthocyandidins was 2.0mg/ml, adsorption and desorption velocity were 1.0ml/min, and desorption agernt was 40% ethanol solution, the purity of proanthocyanidins was 85.8% and the recovery rate of proanthocyanidins was 86.6%.5. Then, membrane was used in the separation of proanthocyanidins. The supermatant was operated by ultrafiltration with cut-off molecular weight 1k, 5k and 10k. The membrane of cut-off molecular weight 5k was selected as the best ultrafiltration membrane. The optimum conditions were as follows: pressure 0.3Mpa, temperature 20±2℃, concentration 0.95mol/L, retention rate was 90.3%, removal of impurity was 99.4%. In addition, the cleaning method of the membrane was studied after the ultrafiltration. The results showed that the effect of hydraulic cleaning was not good at the cleaning of fouled membranes. The influences of different chemical cleaning methods (0.1mol/L HCl solution, 0.1mol/L NaOH solution and 1:30 NaClO solution) were investigated, the result showed that 1:30 NaCIO solution was the best chemical reagent, the membrane recover coefficient was 75.0%. However, using the 0.1mol/L NaOH solution clean the fouled membrane before 20min, then, using the 1:30 NaCIO solution, the membrane recover coefficient was 85.4%, so it was the best cleaning method.