Improved egg yolk pasteurization using sublethal moderate pressure pre-treatments

Egg yolk (EY) thermal pasteurization (TP; 60 °C/3 min) preceded by pressure pre-treatments (50 – 400 MPa/5 min) was evaluated, as an attempt to replace commercial TP (60 °C/6.2 min). These combined treatments inactivated 1.8 to at least 6.1 log10 cycles of Salmonella Senftenberg 775/W, whereas commercial TP achieved 3.3 log10 cycles, probably associated with a reduction of the microorganism's thermal resistance induced by pressure. Generally, soluble protein and total carotenoids of raw EY decreased after treatments, and viscosity and secondary lipid oxidation increased, whereas EY treated by moderate pressure (MP) before a shorter TP (MP-TP) was 1.2-fold less viscous and oxidized than commercial TP EY. Improved emulsifying properties were found for MP-TP EY (1.3 – 1.7-fold), while for commercial TP a more stable emulsion was produced. The fatty acids profile remained stable after treatments, while the volatile profile suffered changes, especially for MP-TP. A traditional dessert prepared with MP-TP (90 MPa) EY showed a greater overall sensory acceptability. Therefore, the results open the possibility to use MP pre-treatments for a subsequently shorter TP, as an alternative to commercial TP, allowing in general to obtain EY with better properties and similar microbial safety.