Research On Preparation And Characterization Of Mussel Protein Powder By Pulsed Electric Field Assisted Enzymatic

This study is supported by two projects: the Jilin modern agriculture key research project-key technologies of mussel products processing and comprehensive product development(20150204034NY) and Changchun modern agricultural technology development support project-key technology of mussel products processing and comprehensive utilization of mussel resources(13NK13).Freshwater mussel, belonging to bivalve mollusk, is widely cultured and has low prices in China. The mussel meat has a high protein content, low fat content and high nutritional values. Songhua River of Jilin Province is rich in wild mussel; the annual output of mussel is up to 3000-4000 t and salvage costs only 1.0-1.2 yuan/kg. However, the resources of mussel are not fully utilized, only a small portion is used as feed, the majority is discarded directly and result in pollution. Exploitation of mussel has benefits to improve economic efficiency of mussel and environmental protection; and has far-reaching significance. Pulsed electric field(PEF) assisted enzymatic method is applied to optimize the extraction conditions of protein from mussel. The protein extracts are treated with yeast and activated carbon to reducing off-odour, and dried by spray drying equipment. Also, the characteristics of mussel protein powder were analyzed to provide a theoretical basis for the comprehensive utilization of mussel.1. The method of Na Cl, alkali and enzymatic were used to extract protein from mussel to obtain the optimum extraction univariate conditions. The contrast test shows that protein extraction yield of protein by enzymatic method was higher and this method is better. The optimal conditions of enzymatic method were concentration of enzyme of 4000U/g, p H of 5.5, temperature of 50℃, concentration of protein of 4% and reaction time of 2h.2. The method of pulsed electric field assisted enzymatic method was used to extract protein from mussel. Response surface methodology design was applied to optimize the conditions of PEF for the protein from mussel.(1) Response surface was applied to get the quadratic regression equation between extraction yield of protein(Y) from mussel by pulsed electric field and liquid ratio(X1), pulse number(X2), enzymolysis time(X3):Y=-2.65+3.32575X1+4.18312X2+29.63X3+0.0175X1X2-0.167X1X3-0.2575X2X3-0.0809X12-0.24562X22-5.86X32(2) According to the variance analysis, we obtained optimum parameters, which were electric field intensity of 19.29 k V/cm, pulse number of 8.12(ea), enzymolysis time of 2.07 h. The maximum extraction yield of protein was 77.08%. The influence of various factors in the test range on extraction yield of protein of the size of the order: electric field strength, enzymolysis time, pulse number.3. The impact of PEF treatment on properties of mussel protein was studied preliminary. The results show that the protein solubility and emulsifying properties were increased; foaming properties were reduced by the treatment of PEF. The stretching vibration of N-H and triple helix structure was affected by PEF treatment.4. The optimal conditions of activated carbon method were: concentration of activated carbon of 1%, reaction temperature of 30℃,reaction time of 30 min. The optimal conditions of yeast method were: concentration of yeast of 1%, reaction temperature of 35℃,reaction time of 60 min. According to contrast and composite test, yeast method was selected to reduce the off-odour of mussel protein in this study.5. The influence of operating parameters on quality of the spray drying mussel protein powder was studied. The optimal conditions were: feed concentration of 15-20%, inlet temperature of 180℃, the amount of wind of 80%. The mussel protein powder obtained by this condition has high ratio of output, low water content, good solubility, good fluidity and easy to disperse.6. The mussel protein powder has a high protein content, low fat content and good solubility; good oil absorption and foaming capacity; certain water holding capacity and emulsifying properties; the molecular weight of protein is low; essential amino acid content is high with a reasonable amino acids. Innovation:Pulsed electric field assisted enzymatic method is applied to obtain mussel protein powder with excellent performance and it can be used as food additives with high quality, and provide a new way for mussel meat processing.