Abstract:bstract： 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 3.23%) 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 2 450 MHz. The results showed that the pickling rate of salted 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 2 450 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 2 450 MHz. Additionally, the penetration depth at 915 MHz was greater than that at 2 450 MHz. The correlation between penetration depth and salt content in egg whites was fitted with a polynomial equation, and a good correlation (R2>0.90) was found between the two in the wine-soaked group A.
