| Based on liquid egg (whole egg liquid, egg white liquid and egg yolk liquid) as the research object, by studying the different sterilization conditions and the influence of the functional properties of liquid egg microorganisms, can identify health and safety can be ensured and the maximum protection of its functional properties of the optimal sterilization process conditions, and the shelf life of liquid egg is studied under the condition of cold storage and the change of functional properties. Finally add sugar and salt effect on thermal stability and functional properties of liquid egg, provide theoretical guidance for the liquid egg production, promote the production and development of liquid egg processing industry.First, the optimization of liquid egg pasteurization conditions, using the Design-expert8.0CCD optimization software. The results are as follows:the optimal sterilization conditions of whole egg liquid is:temperature63℃, time4min, bacteria fatality rate can reach98.33%, foamability of0.49; The optimal sterilization conditions of egg white liquid is:the temperature59.5℃, time of4.5min, bacteria fatality rate can reach99.68%, foamability of0.59; The optimal sterilization conditions of egg yolk liquid is:the temperature63.5℃,4min, bacteria fatality rate can reach99.69%, emulsifying activity can reach0.69. Optimize the sterilization conditions and sterilization conditions prescribed by the state, there were no significant differences in the aspect of bactericidal effect.and less effect on the egg liquid functional properties. Sterilization of egg liquid were negative for salmonella detection, other microbial indicators in line with the relevant national standards. Visible by the response surface method can realize multi-objective simultaneous optimization of liquid egg pasteurization process parameters, to ensure food safety, as well as the maximum reduce the effects of sterilization of egg liquid functional properties, with practical application value of the liquid egg sterilization process parameters.Second, the shelf life of liquid egg is studied under the condition of cold storage and the change of functional properties. Place the egg in the refrigerator freezer storage. The results show that without the sterilization of liquid eggs under a cold storage for a period of4d, improved significantly after pasteurized eggs on the shelf life of liquid, under the condition of sterilization in refrigerated egg liquid can reach12d shelf life.Whole egg liquid, liquid whole egg after sterilization treatment the protein solubility fell to60.6%from63.2%eggs; Blister dropped from0.51to0.48; Foam stability from0.45to0.52; Emulsifying activity fell from0.53to0.50; Emulsion stability dropped from7.4to7.1; pH from7.54to7.63; Viscosity300mPa·s dropped to273mPa·s. With the extension of cold storage time, the sterilization of liquid whole egg protein solubility fell to51.0%from60.6%when it’s cold; Blister dropped from0.48to0.35; Foam stability dropped from0.52to0.50; Emulsifying activity fell from0.50to0.43; Emulsion stability dropped from7.1to6.3; PH dropped from7.63to7.49; Not significantly affect the viscosity.Liquid egg white, egg white liquid after sterilization treatment the protein solubility fell to61.1%from64.0%eggs; Blister dropped from0.56to0.51; Foam stability from0.68to0.74; Emulsifying activity fell from0.51to0.48; Emulsion stability dropped from7.4to7.0; pH stable at around7.6; Viscosity310mpa·s dropped to281mpa·s. With the extension of cold storage time, the sterilization of liquid egg white protein solubility fell to51.2%from61.1%when it’s cold; Blister dropped from0.51to0.38; Foam stability dropped from0.74to0.72; Emulsifying activity fell from0.48to0.42; Emulsion stability dropped from7.0to6.1; pH dropped from7.61to7.54; Not significantly affect the viscosity.Egg yolk liquid:egg yolk liquid after sterilization treatment the protein solubility fell to59.6%from62.6%eggs; Blister dropped from0.27to0.23; Emulsifying activity fell to0.69from0.74, sterilization of foam stability, emulsifying stability, pH had no obvious effect; Viscosity1025mpa·s dropped to898mpa· s. With the extension of cold storage time, the sterilization of liquid egg yolk protein solubility fell to54.7%from59.6%when it’s cold; Blister dropped from0.23to0.16; Foam stability dropped from0.61to0.44; Emulsifying activity remain at around0.67; Emulsion stability dropped from7.4to6.3; pH dropped from7.6to7.5; Not significantly affect the viscosity.Liquid eggs pasteurized and cold storage of the objective is to prolong the shelf life, from the experiment result, as the cold storage time extension of microbial began breeding, functional properties of egg liquid also fell, pasteurized extend the shelf life of the egg liquid, to increase its sales radius, suggested that food enterprises adopt the way of refrigerated transport, processing and application as soon as possible.Finally, add sugar and salt is studied for pasteurized liquid egg functional properties, the influence of adding amount of between2%and10%respectively. Results show that adding2-10%of white granulated sugar and salt can improve the heat resistance of liquid egg, add6%～10%sugar can improve foam stability and emulsification stability of liquid egg, add6%～10%of salt can make the liquid egg still has good emulsifying power after sterilization and foaming power. According to the amount of added salt, sugar, sterilization of liquid level of functional properties is better than that of fresh eggs, thus adding6%～10%of salt, sugar to improve the heat resistance of liquid egg, make its higher sterilization intensity, maintain good functional properties is an effective method. Food enterprises in the actual production, you can add just the right amount of white sugar and salt to obtain different functional properties requirements of liquid egg products. |
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