Parameter optimization for quickly salted egg by using ultrasonic-pulsed pressure technology

Abstract: The pickled cycle of salted duck eggs is a very long time. It usually takes twenty days to thirty days (in spring and summer) and forty days to fifty days (in autumn and winter) to make the salted duck eggs. Therefore, reducing the time of making salted eggs became the issue which domestic scholars were concerned about. The quality of salted duck eggs has the characteristics of moderate salinity, deliciousness, pure protein, delicate, crispy yolk, and the flow of yolk oil. Ultrasonic technology and pulsed pressure technology was applied to accelerate the process of salting duck eggs. We fabricated a rapid salted experimental apparatus of a duck's egg, which mainly contained the pressure vessel, the air compressor, the circulating system, heating devices, and control systems. The effects of the pulse pressure amplitude, the high pressure holding time/atmospheric pressure holding time ratio, and the ultrasonic acting time on the salt contents of egg white (EWSC) and salt contents of egg yolk (EYSC) were studied by single factor methods: the efficiency of water cycle pulse ratio on the salted eggs, the efficiency of water cycle time on salted eggs, the efficiency of high pressure value on salted eggs, the efficiency of high pressure pulsation ration on salted eggs, the efficiency of salting time on eggs, and an orthogonal array design methods. The experiment based on a single factor showed that: the various water cycles it played a significant role in increasing salt content of a egg yolk with the time point 1 d, which showed the best efficiency; pulsating pressure has a great promotion effect on the salt content in the egg white and yolk with the range of 120-160 kPa. Under the same condition of salted time, the increase of pressure pulsating will reduce the effect of pulsating pressure. The orthogonal experimental results showed that during the three day salting with a 24% salt solution under 30℃. To obtain optimal quality of salted eggs and the optimum mass transfer rate, a solution was obtained under the following conditions: pulse pressure amplitude was 140 kPa, and high pressure holding time/ atmospheric pressure holding time ratio was 4 min:16 min, the ultrasonic acting time point was the first day's, Ultrasonic pulsation ratio was 2 min:10 min, and the ultrasonic acting time was 132 min. The protein content was 4.61%, the egg yolk salt content was 2.12%, and the difference of salt was only 2.49%. Delicate protein, moderate salty; crispy yolk and the flow yolk oil were evaluated by a sensory method. The production cycle of the traditional salted eggs method was shortened by 90%, and it was conducive to the industrial production of salted duck egg. Because the applied pressure vessel volume is limited, it cannot be used for large quantities of salted duck egg tests. In the future, the egg-salting device can be scaled into the mechanization and automation of production of efficient Chinese egg products processing equipment that can quickly salt duck egg without pollution.