鸭蛋快速腌制过程中蛋清的介电特性

Study on Dielectric Properties of Duck Egg White During Quick Pickling Process

为探究鸭蛋在快速腌制过程中蛋清介电特性的变化,将鸭蛋分别进行直接腌制、在醋浸泡液(乙酸体积分数为1.45%)或酒浸泡液(乙醇体积分数为3.22%)中浸泡20 min后再进行腌制,采用同轴探针技术在0.3~3.0 GHz下测定了不同腌制方法下分别腌制5、10、15、20、25 d时蛋清的介电特性,在915 MHz与2450 MHz下分析其介电特性、穿透深度与蛋清含盐率之间的关系。结果表明,经过乙酸与乙醇的浸泡,鸭蛋腌制速度提高,醋浸泡组腌制速率较对照组(直接腌制)可加快40%(P<0.05)。随着频率增加,蛋清介电常数与介电损耗均下降,二者在低频时(0.3~1.0 GHz)下降速率均高于高频(1.0~3.0 GHz)。腌制过程中,随着含盐率的增加,介电损耗呈现出升高的趋势;相同腌制时间,醋浸泡组介电损耗高于对照组与酒浸泡组。在915 MHz与2450 MHz时,酒浸泡组的介电常数随含盐率上升呈现下降趋势,对照组与醋浸泡组则相反。随着腌制时间的延长,蛋清穿透深度在915 MHz与2450 MHz时逐渐下降,915 MHz的穿透深度大于2450 MHz。将穿透深度与蛋清含盐率之间的相关性进行多项式拟合,酒浸泡组中二者具有良好的相关性(R2>0.9000)。

To investigate the changes in dielectric properties of duck egg white during rapid pickling,duck eggs were pickled directly,or soaked in vinegar(with acetic acid volume fraction of 1.45%)or wine(with ethanol volume fraction of 3.22%)for 20 minutes before pickling.The dielectric properties of the egg white were measured using coaxial probe technology at frequencies from 0.3 to 3.0 GHz after being pickled by different methods for 5,10,15,20,and 25 days.The relationship between the dielectric properties,penetration depth,and salt content of the egg white was analyzed at frequencies of 915 MHz and 2450 MHz.The results showed that the pickling rate of duck eggs increased after soaking in acetic acid and wine,and the pickling rate of the vinegar-soaked group could be accelerated by 40%compared with the control group(direct pickling)(P<0.05).As the frequency increased,the dielectric constant and dielectric loss of egg white decreased.However,the rate of decrease was higher at low frequencies(0.3~1.0 GHz)compared to that at high frequencies(1.0~3.0 GHz).During the pickling process,the dielectric loss increased with the increase of salt content.Moreover,the vinegar-soaked group exhibited higher dielectric loss than both the control group and the wine-soaked group,for the same pickling duration.At 915 MHz and 2450 MHz,the dielectric constant of the wine-soaked group showed a decreasing trend as the salt content increased,while the control group and vinegar-soaked group showed an opposite trend.As the pickling time increased,the penetration depth of egg white gradually decreased at both 915 MHz and 2450 MHz.Additionally,the penetration depth at 915 MHz was greater than that at 2450 MHz.The correlation between penetration depth and salt content in egg whites was fitted with a polynomial equation,and a good correlation(R2>0.9000)was found between the two in the wine-soaked group.