Study On Extraction Of Proanthocyanidins From Grape Seeds

By studying conditions of extracting and purifying proanthocyanidins from grape seeds, the separation process of proanthocyanidins from grape seeds was established in this paper, which was simple and reasonable. The process is composed of three parts: extraction, column chromatography, and precipitation.In extraction process, five extraction conditions were studied: temperature, extracting time, concentration of solvent, amount of solvent and ratio of solvent to grape seed. With the extraction yield of proanthocyanidins and the selectivity of extraction as optimal condition, the optimal extraction conditions are as followed: solvent 60% ethanol, temperature 30℃, solvent volume to grape seeds weight is 3:1, extracting for 3times,and the time is 30min respectively. Extraction yield of proanthocyanidins was about 92.7%, the content of proanthocyanidins in product is 57.2%.After studying nine macro porous adsorption resins with column chromatography, comparing with polyamide chromatography, it was revealed that X-5 resin chromatography was proper in purifying proanthocyanidins. The results of experiments show that the adsorption isotherm can be correlated with Freundlich isotherm equation. When the equilibrium concentration is 180mg/ml, the adsorption equilibrium time is about 3h. When the flow rate was 0.5BV/h, and the Co was 64.5mg/ml, the static adsorption capacity is 153.2mg/g resin; if Co=42.3mg/ml, the static adsorption capacity is 141.8mg/g, by which the maximal loading capacity in industrial adsorption column can be estimated. Desorption can be achieved by 40% ethanol. Desorption ratio is 86.1%. The purity of Proanthocyanidins is more than 80%.After one deposition, the purity of proanthocyanidins is 97.7%, and the yield is 99.1%, the deposition solvent was petroleum ether, the proanthocyanidins was dissolved in acetic ether, and the ratio is 4:1.In the end, the 97.7% content of proanthocyanidins in product can be got, and the yield of proanthocyanidins is 79.1% by the process. The value of technology is important in industrial production.