Agitation of liquid eggs during ohmic heating pasteurization—Experimental and computer simulation study

Abstract

AbstractTraditional pasteurization process of liquid eggs deals with food safety regulations; however, detriment of functional quality properties is also promoted. In this study, an agitated ohmic heating system at 20 kHz was evaluated experimentally and using a 3D computer simulation model, developed using COMSOL Multiphysics. The accuracy of the model was successfully validated by experimental temperature profiles results, showing low errors (RMSRE < 10%), at two different locations. The temperature distribution and flow behavior of liquid eggs during processing were analyzed using the 3D model. Safety and quality retention assessments of processed liquid eggs were performed by calculating the thermal pasteurization value (P‐value) and thermal protein non‐denaturation ratio (X), respectively. A better temperature uniformity was found under 20 rpm than at 10 rpm of rotational speed (temperature difference was reduced from 1.8 to 1.4°C and 5.1 to 4.3°C for egg white and yolk, respectively). Moreover, the degree of protein denaturation (at the point where the P‐value was accomplished) at 20 and 10 rpm were 0.92 and 0.89, and 0.99 and 0.98 for egg white and yolk, respectively. These results are of potential value for the design of ohmic pasteurization systems for fluid foods.Practical applicationsThe applications of the findings of this study include but are not limited to: (a) utilize the measured electrical conductivity values at 20 kHz of egg whites and yolks for further studies; (b) predict the temperature and velocity profiles and distributions of liquid eggs during agitated ohmic pasteurization processes using the developed 3D computer simulation model; (c) evaluate improvements in temperature uniformity, pasteurization efficiency, and quality retention by fine‐tuning processing parameters as evaluated in this study; and (d) use the design and the conducted analysis of agitated ohmic heating system of liquid eggs for developing novel pasteurization applications of fluid foods.