ABSTRACT
    Pulsed Electric Fileds (PEF) is a non-thermal food preservation technology that is being evaluated as an alternative for conventional preservation processes based on heat. This technology is characterized by allowing obtain a microbiologically safe product with greater respect for the nutritional components than the conventional heat treatment.
    The studies that comprise this doctoral thesis try to assess the suitability of PEF technology to deal an acidic food of the complexity of a mixed orange juice and milk beverage stabilized by pectin addition. This has been carried out by PEF inactivation kinetic studies of spoilage and pathogenic microorganisms present in this kind of food (Escherichia coli and Saccharomyces cerevisiae) and destruction of enzymes that cause the loss of quality (Pectin methylesterase, PME), obtaining experimental mathematical models thar relates the electric field intensity, the treatment time and temperature with the inactivation obtained. Similarly, the effect of the PEF on nutritional compounds content (water-soluble vitamins and ACE inhibitory peptides) was evaluated.
    Finally, were conducted preliminary studies of technology validation from the point of view of food safety through studies of sublethal damage, possibility of generating transformants and variation of protein profile in Escherichia coli and Lactobacillus casei