| Cooking was one of the key steps in the Engraulis Japonicus dry products processing.The cooking soup contain plenty of protein,amino acid,nucleotides and some other mineral elements.2 tons of cooking soup was produced when 1 ton dry products processed.But almost no recycle of the biological resources and directly discard into environment to cause pollution.It's a necessary trend for modern aquaculture enterprises recycling the cooking soup in order to achieve clean production methods.Turning the waste into treasure was the inevitable trend of modern aquaculture of high value processing.The original liquid of Engraulis Japonicus was low concentration and contain a lot of salt.In order to satisfy the processing request and solve the problem of less storage space for offshore processing ship,it's a necessary desalination and then through the reverse osmosis concentrating shipped to shore for further processing.In this study,electrodialysis and membrane concentrating technologies were used for recovering protein and amino acids from Engraulis Japonicus cooking soup and to explore the concentration technologies,the main contents and results of this paper were as followings:(1)Compared with the heterogeneous ion exchange membrane,the homogeneous membrane has the advantage of big limiting current intensity(I=6.5 A),desalination rate above 90%,low water soluble protein and low free amino acid loss rate,the loss rate was 25.55%and 13.77%,respectively.The homogeneous membrane was more suitable for the Engraulis Japonicus cooking soup electrodialysis desalination.It was beneficial to improve the efficiency of desalination when the current was 3 A and the flow rate was 40 L/h.(2)The effect of electrodialysis desalination on free amino acid content of the Engraulis Japonicus cooking soup was studied.The losses of free amino acid increased with the electrodialysis extension of time,phenylalanine and arginine loss rate was great,70.60%and 57.08%,respectively.At the same time,the reduction rate of the volatile base nitrogen and trimethylamine were 56.45%,72.90%,respectively.(3)The effect of electrodialysis desalination process on molecular weight and ion was studied.Small molecular weight of the water-soluble protein has the electromigration phenomenona and the large molecular weight of counterpart increased with current and pH increasing,respectively.Under the same operating conditions,SO42(85.97%)ion removal rate was less than Cl-(93.34%)and has a significant removal of the heavy metals,Cr?As?Cd?Pd?Hg removal rate was 28.93%?38.51%?67.04%?54.77%?41.23%,respectively.In which the highest removal rate was Cd(67.04%).Electrodialysis also remove the key material of fishy volatile flavor substances,such as hexanal,trimethylamine.(4)Using an electrodialysis(ED)channel mass balance and fundamental electrochemical equations,a mathematical modeling was applied to model separation from brine waste using ED:(?)Application of the regression equation calculate a as a function of flow rate,voltage and feed concentration:?=1.766×10-7 C0+2.213 × 10-7E+1.476 × 10-7Q-7.657×10-6(5)The reverse osmosis technology has a highly concentration efficiency,less loss of nutrients,amino nitrogen and soluble protein concentration 4.29 times and 5.80 times,respectively.The reverse osmosis membrane flux is bigger and condensed time is short when the operating pressure at 1.50 MPa,the velocity is 1.60 m/s and the temperature 30?,the reverse osmosis membrane flux was 14.56 L/m2·h.The growth rate of total aerobic bacterial count and total volatile base nitrogen(TVB-N)value was minimum compared to the concentration factor.(6)For the membrane fouling that was produced by concentrating cooking soup,complex chemical cleaning agent sodium phosphate polymer+SDS+EDTA have higher cleaning effect of reverse osmosis membrane cleaning,when cleaning 30 min under 30?,the flux recovery ratio was 95.80%. |
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