Impacto del uso de tecnologías no térmicas sobre distintos parámetros nutricionales y de calidad en alimentos líquidos / Non-thermal technologies impact on nutritional and quality parameters in liquid foods

Resumo

In the last decade have appeared in the Spanish market new products based on mixtures of fruit juices and milk as well as beverages mixtures of fruit and/or vegetables, which have a good acceptance by consumers and with a high nutritional value largely due to its high content in bioactive compounds as well as antioxidant capacity. Traditionally, liquid food such as fruit and/or vegetables juices, as well as milk, have been preserved by thermal treatment such as pasteurization and sterilization. However these processes can cause loss of compounds responsible for the organoleptic and nutritional quality of food. Currently there is a growing demand by the consumer for minimally processed food and which in turn are safe from the microbiological point of view, a fact that is driving the development of new conservation methods. Nonthermal processes such as high hydrostatic pressure, pulsed electric fields and ultrasound, which can be used with this goal without affecting the quality of food. Although the effectiveness of these treatments is known for safe food, is now when is possible to produce the greater technological advances for it to marketing. In the present doctoral thesis, the main objective is to establish the conditions of nonthermal processing to obtain beverages with a high content in bioactive compounds as well as antioxidant capacity. In addition it is important to compare the effects of these treatments on the organoleptic and nutritional characteristics, with those occurring after the implementation of a traditional heat treatment. Subsequently, also it was studied the degree of permeability of the cell membranes of blueberries using the extent of the impedance, to optimize the parameters of processing and use thermal and nonthermal processing in the extraction of bioactive compounds with antioxidant capacity.