Study On The Abalone Viscera Protein Hydrolysis And Its Characters Changes By Pulsed Electric Field

Abalone’s viscera was used as main raw material in this study, the optimumconditions of enzymatic extraction and assisted extraction by PEF were determined and theimpact of PEF treatment on abalone’s viscera protein product yield rate by PEF treatmentwas studied, so as the changes in the protein structural properties and functional properties,especially on which is the changes of protein molecular weight, solubility and viscosity.Therefore, the results provided a theoretical basis for the reaserch and development (R&D)and production of abalone seafood seasoning.The protein content of abalone’s viscera was tested as10.54%, which was suited forprotein resources. Pepsin, composite protease, alkaline protease, trypsin, seafood dedicatedhydrolase and flavourzyme were selected to the enzymatic test, the degree of hydrolysis,nitrogen recovery, the degree of hydrolysis and sensory score was studied as the evaluatingresults of hydrolysis.experiment suggested that trypsin, seafood dedicated hydrolase andflavourzyme were more suited for the hydrolysis of abalone’s viscera.After treatment of PEF, the single enzyme technology, the mixed enzyme technologyand the segmentation of enzyme technology, the hydrolysis performance metrics werecompared and the optimun technic was determined by the response surface experimental design,response surface experimental design and orthogonal experimental design respectively, which thedegree of hydrolysis, nitrogen recovery, the degree of hydrolysis and sensory score wasstudied as the evaluating results of hydrolysis. Experiment suggested that the segmentationof trypsin and flavorzyme got best result of hydrolysis, the optimum process parameterswere as follows:(a) the hydrolysis of trypsin-stage: hydrolysis temperature of54.88℃for4.0h, pH value of7.10, the amount of enzyme0.15%, liquid to solid ratio(v/w)5:1.(b)flavourzyme-stage hydrolysis:hydrolysis temperature of55℃for3.0h, pH value of6.0,the amount of enzyme0.20%. Under these conditions, the hydrolyzate hydrolysis yield,degree of hydrolysis, nitrogen yield and flavor score values were respectively35.24%,52.87%,39.99%and162.70.The effect of the electric field strength, the processing time and material-liquid ratio to the degree of hydrolysis, nitrogen recovery was explored in PEF pretreatment ofabalone’s viscera, which the degree of hydrolysis, nitrogen recovery, the degree ofhydrolysis and sensory score was studied as the evaluating results of hydrolysis.Experiment suggested that compared the process without PEF pretreatment, the processwith PEF treatment obviously improved the effect of enzymatic hydrolysis, more fullyhydrolyzing abalone’s viscera protein, and higher product yield. The optimum processparameters of PEF pretreatment: electric field strength of20kV·㎝-1, processing time of600μs, the liquid-material determined to be5:1.Under these conditions, the hydrolyzatehydrolysis yield, degree of hydrolysis, nitrogen yield and flavor score values wererespectively42.35%,52.87%,46.24%and175.20.The effect of PEF on the structural properties and functional properties of abalone’sviscera proteinwas studied. The results showed that: the macaromolecular substance ofabalone’s visceral was degraded by the treatment of PEF, decreasing the molecular weight.After got through the high performance liquid chromatography GPC column, tworespective peaks of two kinds of abalone’s viscera protein were maintained, indicating thatthe protein components of two kinds of abalone’s viscera protein were uniform and thesecondary structure of protein molecules were changed by PEF. The protein solubility,,emulsifying and emulsion stability was increased，foam stabilityandviscosity of the proteinwas reduced by the treatment of PEF. In particular, the increase of solubility and thereduction of viscosity have good effect on the improvement the solubility of spices,providing a theoretical basis for the development of abalone condiments.