Research note: Study on liquid-liquid phase separation of thick and thin egg white

"Gel-like" thick egg white (TKEW) and "solution-like" thin egg white (TNEW) are not mutually soluble in fresh egg white, showing a natural liquid-liquid phase separation phenomenon. The effects of storage temperature, storage time, ultrasonic force, mechanical stirring and chemical ions on the stability of liquid-liquid phase of TKEW and TNEW were systematically analyzed in this paper. It was found that the collapse of TKEW gel structure was the key to cause two phase separation. Room temperature storage was easier to cause the structure of TKEW collapsed and the viscosity decreased, which led to the phase separation interface between TKEW and TNEW began to lose stability. Besides, ultrasonic treatment, stirring and phosphate-buffered saline (20 mmol/L) in acidic environment also reduced the proportion of TKEW, and result in the disappearance of the two-phase interface. While, the salt at physiological concentration was found to contribute to the stability of TKEW. The rule of liquid-liquid phase separation of TKEW and TNEW provided an important basis for egg white storage and diversified utilization.