全蛋液的高压CO_2杀菌工艺参数优化

Optimization of whole egg liquid sterilization technology using high pressure CO_2

为了达到杀灭蛋液中沙门氏菌和避免热巴氏杀菌引起鸡蛋蛋白变性的目的,该研究采用高压CO_2(high pressure carbon dioxide,HPCD)对全蛋液中沙门氏菌进行冷杀菌。通过单因素试验分析CO_2压力、杀菌温度、杀菌时间和搅拌速度对全蛋液中沙门氏菌的杀菌效果,并利用Box-Behnken响应面设计建立了沙门氏菌杀灭的二次多项回归模型。得出最佳杀菌工艺为:在CO_2压力为30 MPa、温度为40℃、时间为60 min、搅拌速度为125 r/min的条件下,能够使全蛋液中3×10~6~3×10~7 CFU/m L的沙门氏菌完全杀灭。同时还比较了巴氏杀菌和HPCD杀菌对全蛋液的货架期、功能特性的影响。研究结果表明:与巴氏蛋液比较,HPCD使全蛋液货架期延长至39 d;起泡能力和起泡稳定性分别提高了53.63%和2.38%;乳液Zeta电位提高至7.66 mV,提高了乳液稳定性;全蛋液的粘度、粒度储能模量和损耗模量分别降低,呈现粘弹性性流体的特性。该研究结果可为HPCD杀菌技术应用蛋液产品提供参考。

The production of egg liquid is often contaminated with Salmonella.Eggs and their products are at a higher risk of infection or contamination of Salmonella,with up to23.1%.In the traditional thermal pasteurization process,egg protein is prone to degeneration coagulation.For the purpose of killing salmonella and reducing the functional properties of the egg liquid,in this experiment,we used high pressure carbon dioxide(HPCD)to sterilize salmonella in whole egg liquid.HPCD mainly uses the synergistic effect of temperature(5-60℃)and CO2pressure(0-50MPa)to diffuse CO2molecules into the medium and control the metabolism of microorganisms by acidification,chemical action and mechanical action.In order to achieve the purpose of sterilization,this study examines the effects of pressurized carbon dioxide,temperature,and stirring speed on the bactericidal effect of Salmonella in whole egg liquid.Single-factor analysis was conducted to measure the effects of pressurized carbon dioxide,temperature,time and stirring speed on the sterilization efficacy.On the basis of single factor,Box-Benhnken was used to optimize the Salmonella sterilization parameters and a quadratic polynomial model was established for the logarithmic reduction of viable count of Salmonella.At the same time,the effects of pasteurization and HPCD sterilization on the particle size,foaming,emulsifying and rheological properties of the whole egg liquid were also investigated.Through the Design-Expert software,the variance and significance of the regression model were analyzed,and we can conclude that the effects of pressurized CO2,temperature,time and stirring speed on Salmonella inactivation are mostly significant(P<0.0001).The interactions between pressurized carbon dioxide and time,pressurized carbon dioxide and stirring speed,temperature and time,temperature and stirring speed,time and stirring speed are mostly significant(P<0.0001).The interactions between stirring speed and temperature are significant for sterilization(0.0001<P<0.05).The interaction between pressure and temperature is not significant for sterilization(P>0.05).Under the condition that the pressurized carbon dioxide,temperature,time,and stirring speed were30MPa,40℃,60min and125r/min,respectively,lethal logarithm could reach7.25.Compared with pasteurized egg liquid,the shelf life of the whole egg liquid treated with HPCD has been extended by39d;the foaming ability and foaming stability of whole egg liquid increased by53.63%and2.38%respectively(foaming ability:from111.51%to140.30%;foaming stability:from80.72%to92.14%).HPCD sterilization increased the absolute value of Zeta potential(from4.71mV to7.66mV),which improved the stability of the emulsion.After HPCD treatment,the rheological properties of whole egg liquid had no significant difference with the original egg liquid.The whole egg liquid of particle size,storage modulus and loss modulus decreased by HPCD treatment,showing the characteristics of pseudoplastic fluid.However,the foaming ability of whole egg liquid reduced with pasteurization(from111.51%to86.67%);the foaming stability of whole egg liquid increased(from80.72%to89.76%).Pasteurization reduced the absolute value of the Zeta potential of the egg liquid(from4.71mV to1.36mV),and the whole egg liquid after pasteurization increased particle size,denatured protein aggregation,and increased storage modulus and loss modulus.This study provides reference for the sterilization of egg liquid products with HPCD sterilization technology.