The growing demand of food with characteristics near to the fresh product is enhancing the development of nonthermal preservation technologies. Among them Hydrostatic Hydrostatic Pressure (HHP) and the Pulsed Electric Field (PEF) processing are the most promising. These technologies allow the preservation of the overall food quality (flavor, aroma, color and vitamins) in a greater extent than thermal technology. The microbial and enzyme inactivation degree obtained through these technologies allow extending the shelf-life of the product at refrigeration conditions facilitating its commercialization. The general objective of this doctoral thesis has been to study the possibility of applying a PEF and HHP processing alone or combined with thermal treatment in a new beverage based on the mixture of orange juice and milk including microbiological and quality aspects. The work plan began with the preparation and physicochemical and sensorial characterization of the new product, choosing the adequate formulation for developing the kinetic and shelf-life studies. The main quality parameters in an orange juice based product are the enzyme activity and the aroma content (volatile compounds concentration). In orange juice, pectin methyl esterase (PME) is one of the most relevant enzymes. A study of the influence of PEF, HHP and thermal processing on PME inactivation was developed. The different technologies could inactivate 90% of PME. The appearance of two fractions with different resistance to the treatment was observed and a biphasic model was used to describe PME inactivation curves by a combined HHP and thermal treatment in the product. The study of the effect of the different processing technologies on aroma content (volatile compounds concentration) was also performed. The results revealed PEF technology as the best technology to preserve the fresh product original aroma. Once quality parameters studies were established, the microbiological aspects related to the product were also studied. The influence of PEF processing variables on the inactivation of a spoilage microorganism (Lactobacillus plantarum) was carried out in the new product. Electric field, treatment time and temperature were the most influential variables, producing higher inactivation with lesser energy consumption. A kinetic study of PEF inactivation of L. plantarum was also done. Weibull model was chosen as the one which best described microorganism survival curves after PEF treatment and the tcw parameter could be considered as an index of the microorganism treatment resistance. Within pathogen microorganisms, it has been demonstrated that Salmonella typhimurium could originate a food safety problem in acid foods such as orange juice. In order to study the microorganism behavior against PEF treatment a kinetic study was done based on the food characteristics such as pH and stabilizer concentration (pectin). It was found that any pH diminishing favored inactivation while the pectin concentration did not have a significant effect. Finally a shelf-life study after PEF and thermal treatment was carried out in the beverage stored at refrigeration temperature. The study showed the PEF technology viability to obtain food with similar thermal treatment shelf-life but better final quality product.