Study On The Extraction And Purification Processing Of Total Flavones In Onionskin

The extraction of active components from vegetable materials is an important direction of vegetable comprehensive processing. This could not only enhance the value of vegetable, but also fully used the wastes of vegetable processing. Onions is one of the important export vegetables in our country, and has numerous useless materials during processing, which courses environmental pollution and resource waste. In this paper, the extraction and purification of flavonoids from onionskin were studied, which can provide some experimental instruction and technical support.Through single factor and orthogonal experiments of normal reflux extraction, the optimum condition of normal reflux extraction was that: the onionskin particle of 60 mesh size,70℃of extracting temperature,80% of ethanol concentration, 1:20 of material to ethanol, first time extracted for 2hs,and then extracted for 1h at the second time. The extracting rate is 4.43%.Investigated the single factor and uniform design experiment of Microwave assistant extraction, the optimum process condition was confirmed that the highest extraction yield of total flavonoids of 4.02% could be obtained when the onionskin particle of 60 mesh size, microwave power was 390W, ethanol-water solvent concentration 40%, ratio of solid to liquid 1:20, radiation time was 9 min. And compared with the normal reflux extraction methods, microwave-assisted extraction has the advantages of faster extraction, lower energy.It were compared that the ability of adsorption and separation to onionskin total flavonoids of six different type of macroporous resin by means of static adsorption test and dynamic test, it shows that the total ability of low pole HPD-600 resin was superior to the other macroporous resin. All process conditions influencing on the process of separation and purification total flavonoids with HPD-600 resin were investigated in detail, the optimum absorption and separation process condition was confirmed when the feed concentration of total flavonoids was 0.52mg/ml, the feed volume was 50ml, pH4; the desorption solvent was 80% ethanol of 60ml, the desorption velocity was 1.0ml/min,the highest content of onionskin total flavonoids of 45.26% could be obtained by the process of separation and puritication.