Continuous flow microwave processing of liquid whole egg: Pasteurization and functional characteristics evaluation

The objective of this study was to assess the impact of continuous flow microwave processing on the pasteurization efficiency and quality attributes of liquid whole egg (LWE). The heating section was accomplished using microwave, while the holding section utilized a water bath, and the process parameters were determined by a developed numerical model. The inactivation kinetics of Escherichia coli, Staphylococcus aureus, and Salmonella Enteritidis were evaluated at three temperatures (56, 60 and 64 °C) and two power-density (8 and 16 W/mL with different flow rates). A 5-log₁₀ reduction was achieved and the Weibull model fitting the survival data well, which contributed to the optimization of microwave pasteurization process. Additionally, microwave promoted the transitions of secondary structures from β-sheet to α-helix and stabilised the system by enhancing the zeta potential value, further improving the emulsifying and foaming properties. The major proteins in LWE were not found to undergo degradation according to the results obtained from SDS-PAGE analysis. The results of this study suggested that continuous flow microwave pasteurization of LWE exhibits potential as a viable alternative to conventional pasteurization methods.

Industrial relevance

The adoption of high-efficiency physical processing methods is imperative for the sustainable and low-carbon advancement of the food industry. This study confirmed the feasibility of continuous flow microwave pasteurization as an alternative to conventional methods for liquid whole egg, addressing key limitations encountered in traditional pasteurization approaches, and the findings offer practical insights for industrial-scale production. Additionally, the development and application of a continuous flow microwave heating system for pasteurizing liquid whole egg provide valuable knowledge for the utilization of microwave treatment in processing high-viscosity and heat-sensitive fluid foods.