| Abalone viscera is full of polysaccharide,which is proved to have many functions,such as antioxidant,antitumor.It shows potential to be developed into health products.Due to the development of industry,sea pollution become more horrible and toxic substances like heavy metals and toxic organics are poured into ocean and accumulated,which result in worse ocean pollution.Heavy metals in living organisms can be gradually accumulated with the food chain.Abalone lives in ocean and feed on seawater and seaweed,which definitely result in amount of heavy metals transferring into their body.How to increase the extraction of polysaccharide and how to remove the heavy metals in polysaccharide are the most important procedure during producing abalone viscera polysaccharide(AVP)and also the precondition to ensure the development of AVP into health care product.AVP liquid,after beating and centrifuging,is used as the material of this study.The first part of this paper is to value the extractive effect of different enzymes and figure out the best enzymatic hydrolysis condition,by choosing the content of AVP and amino nitrogen in enzymatic hydrolysate as index.The second part is to determine the optimum process of the extraction of AVP and analysis the distribution of Cd,Pb,As,by studying the effect of each operations on the content of protein,polysaccharide,Cd,Pb,As,during extracting AVP.After extracting,we will apply the combination method of plate filtration and resin adsorption to remove the residue of Cd,Pb,As,and secondary alcoholic precipitation,dialysis technique,active carbon adsorption and high active white soil adsorption are individually utilized to remove Hg.The detail researches and results were as follows:1.Papain,trypsin,alkali protease,neutral protease and pepsin were used to investigate the effectiveness of hydrolysis.The result showed that papain has obvious effects on enzymolysis and extracting of AVP,as a result 11.7%amino nitrogen and18.3%AVP were achieved.2.To optimize the hydrolysis condition,single-factor experiments were made.As temperature,time,the content of enzyme,substrate concentration and pH were the crucial factors in the process of hydrolyzing,they were studied to discover the best parameters.The best enzymic hydrolysis conditions were as follows:temperature 50?,time 3h,the content of enzyme 4500U/g,substrate concentration 3%,pH 7.0.3.In order to research the extraction of AVP and the distribution of heavy metals,the contents of AVP,protein and heavy metals in each process were detected.The results indicated:(1)Some Cd,Pb,As are exist by binding with protein and some are found free in AVP liquid.Among the free heavy metals,Cd,Pb are insoluble in ethanol but As is not.(2)Hg is distributed in AVP.(3)Both plate filtration and resin adsorption play important roles on decoloring and removing heavy metals.(4)Plate has a function to eliminate protein.4.The combination method of plate filtration and resin adsorption was utilized to remove the residue of Cd,Pb,As in AVP.The result demonstrated that 732 type resin is not only good to remove Cd,Pb,but also play a role on adsorbing protein.However,717 type resin could only adsorb As.After treated by plate and resin,the content of heavy metals in AVP meets limited requirements for hazardous metals in individual products of GB 16740-1997.5.Secondary alcoholic precipitation,dialysis technique,active carbon adsorption and high active white soil adsorption are individually utilized to remove Hg.This experiments demonstrated that high active white soil play roles on removing Hg and increasing the concentration of AVP.6.According to the extraction processing of AVP and the study of removing Cd,Pb,As,Hg,the optimum procedure is:abalone viscera beating—centrifuging—crude AVP—enzymic hydrolysis—centrifuging—plate filtrating?alcohol precipitation—high active white soil adsorption—plate filtration and resin adsorption(732 type and 717 type)—vacuum freeze drying. |
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