ABSTRACT
   The application of new technologies for food processing and preservation aims to meet the growing consumer demand for minimally processed fresh-like foods, with high sensorial and nutritional quality and convenient to prepare (ready-to-eat meals). This has lead the food industry to develop novel non-thermal food preservation technologies that inactivate microorganisms without the need for intense heat treatment, thus obtaining products with similar properties to fresh foods, and preserving the nutritional and sensory properties, while also maintaining their shelf-life.
   The general aim of this work was to study the impact of the application of new preservation technologies, such as Pulsed Electric Fields (PEF) and High Pressure Homogenisation (HPH), on the structure and the main chemical components of food fluids -liquid egg and dressings-. The microstructure and main chemical changes in the protein and lipid fraction of these foods were analyzed. In addition, several physical properties, such as viscosity, color, and foam capacity of liquid egg treated by PEF were studied. Studies were carried out with samples processed by PEF in the SIK (the Swedish Institute for Food and Biotechnology) and HPH at the Universitā di Bologna. The samples were also evaluated after a week of refrigerated storage at 4 ēC.
   The results show that PEF and HPH treatments, when applied at low intensities, can be considered a potential alternative to conventional heat treatment for the preservation of liquid egg, because of its lower impact on the microstructure and chemical properties if compared with pasteurization. Moreover, PEF treatment has little effect on the functional properties of liquid egg. On the other hand, the physicochemical stability of sauces treated by HPH is directly related to the pressure applied during the process. The loss of the natural emulsifiers, when pressure increases, leads to the coalescence of the fat phase and consequently to the emulsion destabilization. However, the lipid fraction of sauces remains chemically stable after HPH treatment.
   
DOCUMENTO I. Memoria

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