Ice rnorphology (size and shape) influence decisively in sensory appreciation, texture and quality of rnany frozen foods. Ice rnorphology is also irnportant in sorne technological processes such as freeze drying and freeze concentration, which influences the efficiency ofthese processes. The overall objective of this thesis was to increase our knowledge about the control on rnorphology of the ice phase in freezing food and related processes such as freeze concentration. Freezing in food and solutions, as well as the rnethods of observation and rneasurernent of ice rnorphology were analyzed, and the role of ice rnorphology in sorne technological applications was discussed. Special attention was put in the architecture or spatial arrangernent of elernents in the structure of the frozen phase and the role in the efficiency of the freeze concentration process. When an ice nucleus begins to grow in a solution, solutes are rejected frorn the ice phase and accurnulate at the solid-liquid interphase, forming a hydraulic systern in the frozen rnatrix (ice phase) with veins or channels between the ice crystals occluding the concentrated solution. Assisted techniques (such as ultrasound or ice nucleation agents) have proven to be irnportant in providing a rnorphology of the frozen phase that irnproves the efficiency of freeze concentration. Other altemative are the use of externa! driving forces such as vacuurn or centrifugation in the recovery of concentrated solutions Propose two novel techniques (vacuurn or centrifugation) in order to use conveniently this hydraulic systern to irnprove efficiency in the separation of solutes in freeze concentration processes, using sucrose aqueous solutions as rnodel sarnples. By applying vacuurn (80 kPa), the efficiency of the freeze concentration was significantly improved over atmospheric conditions showing a higher recovery of solute, approximately 0.5 kg of sucrose obtained per 1 kg of initial sucrose compared to recovery values ranging from 0.16 to 0.3 kg/kg for atmospheric treatments. On the other hand, by applying centrifugation, a high recovery of solutes is achieved, reaching approximately 0.73 kg of sucrose obtained per 1 kg of initial sucrose at 1600 relative centrifuge force (RCF), compared to recovery 0.5 kg/kg using a less centrifuge speed (800 RCF). The high separation efficiency of solutes using assisted techniques for freeze concentration is a consequence of using an externa! driving force that improves the natural separation of gravitational thawing and taking advantage of the microstructural features of the frozen phase. W e can con elude that vacuum or centrifugation in freeze concentration is an effective assisted technique to enhance the separation efficiency.PFCHA-BecasDoctor en Ciencias de la Ingeniería117p.PFCHA-BecasTERMINADA