Study On Extraction And Purification Of Glucoraphanin From Broccoli

Glucosinolates(GLSs)can be degraded into different degradation products,with a variety of biological activities.A broad attention has been paid on the anticarcinogenic activity and ability of improve immunity of glucosinolates.Glucoraphanin is one of the it,whose main degradation product is sulforaphane,which has been found as the strongest anti-cancer substance in vegetables.But sulforaphane is unstable and volatile,so generally products of it were prepared by glucoraphanin.While glucoraphanin can be degraded by myrosinase during the extraction of glucoraphanin from broccoli.Therefore,it is need to study the myrosinase removal of extraction process,purification technology of glucoraphanin extracts of broccoli.This paper mainly used broccoli as raw materials,explored the best extraction process of glucoraphanin from broccoli seeds,the better extraction process of glucoraphanin from fresh broccoli by removed myrosinase,and purification methods of glucoraphanin from broccoli extracts.Finally we got that following conclusions:1.The optimal conditions of glucoraphanin extracted from broccoli seeds by ethanol extraction method was:ethanol concentration:70%,solid-liquid ratio:1:5,extraction temperature:70℃,extraction time:20 min,and repeated extraction two times.Finally the yield of glucoraphanin in broccoli seeds was 5.41 mg/g.2.Compared with the effect of sevag method,tannic acid method,saturated sodium chloride method,silica gel method,and chitosan method to removed proteins in glucoraphanin crude extracts of fresh broccoli,and the effect on the yield of glucoraphanin,finally the sevag method was choosed.3.Through temperature treatment,steam treatment,microwave treatment,NaCl soaking treatment and tannic acid beating treatment to removed myrosinase to extracted glucoraphanin from fresh broccoli.0.20 mg/g glucoraphanin was gotten from fresh broccoli by NaCl soaking treatments.A new extraction method of glucoraphanin from fresh broccoli in high yield that uesd sodium chloride combined with ethanol at room temperature treatment was found,and there was no significant difference compared with the yield of glucoraphanin by optimal method.Thus this method provid a new idea for the industry to remove the myrosinase and extract glucoraphanin from fresh broccoli.4.DEAE Sephadex A-25 was used to purified broccoli seeds extracts.At length,the purified substance was only 0.01 mg/g by analytical HPLC.The effect was not excellent,more broccoli seeds are required and preparative HPLC is needed to get more purified products.5.Compared with the effect of static adsorptive glucoraphanin in broccoli extracts used by D201 strong basic anion exchange resin,D290 strong basic anion exchange resin,717 strong basic anion exchange resin,AB-8 macroporous resin,silica gel,polymer chitosan,acidic alumina,diatomite,reduced iron powder,and active carbon powder,the adsorption rate was respectively 70.54%、86.04%、71.84%、21.9863%、1.85%、22.99%、32.28%、3.92%、69.39%and 99.87%.6.AB-8 macroporous resin,polymer chitosan and silica gel were all with the worse effect on the adsorption rate of glucoraphanin,which were contrary to strong basic anion exchange resin,reduced iron powder and activated carbon powder.Based on that,AB-8 macroporous resin,diatomite and polymer chitosan were selected to adsorbed the impurity substance in fresh broccoli crude extracts and increased the content of glucoraphanin at the same time.The results showed the content of glucoraphanin can’t be raised by AB-8 macroporous resin adsorption,diatomite and polymer chitosan,which in treatment solutions after freeze drying,the ratio were respectively increased-18.18%,1.29%and 0.18%.Then D290 strong basic anion exchange resin,reduced iron powder and active carbon powder were choosed to done desorption experiments.The result showed:active carbon powder and reduced iron powder had significant effect on adsorb glucoraphanin,suitable eluents were difficult to be found for the elution.While glucoraphanin was absorded in D290 strong basic anion exchange resin can be eluted by 0.5M calcium chloride solution,and the elution rate of glucoraphanin was 39.42%.7.D290 strong basic anion exchange resin and 0.5M calcium chloride solution were selected as column filler and the eluent,through dynamic adsorption and described the dynamic adsorption saturation curve and dynamic desorption curve,the results showed that the saturated adsorption of glucoraphanin was 1.08 mg in 0.5 g D290 strong basic anion exchange resin column,0.5M CaCl2 solution can elute 1.03 mg glucoraphanin from it,and the elution rate can reach 95.36%.8.Potassium carbonate solution was added,which with same volume and concentration like calcium chloride solution,in order to removed Ca2+.Eventually the recovery rate of glucoraphanin was 56.67%.By comparison,the content of glucoraphanin was increased by 34.23%before the removal of Ca2+,and compared with the glucoraphanin without purification,it enhanced by 19.81%.