Characterization of Electromagnetic Freezing in Food Matrixes and Model Food
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DEPARTAMENTO DE AUTOMÁTICA, INGENIERÍA ELÉCTRICA Y ELECTRÓNICA E INFORMÁTICA INDUSTRIAL ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES UNIVERSIDAD POLITÉCNICA DE MADRID Characterization of electromagnetic freezing in food matrixes and model food TESIS DOCTORAL Autor: Antonio Carlos Rodríguez Plaza Master en Electrónica Industrial, Universidad Politécnica de Madrid Directores: José Antonio Cobos Márquez Doctor Ingeniero Industrial, Universidad Politécnica de Madrid Pedro Dimas Sanz Martínez Doctor en Física, Universidad Complutense de Madrid (Espacio para la hoja oficial con los datos de la tesis) Agradecimientos Contents ABSTRACT ................................................................................................................ xv RESUMEN ............................................................................................................... xvii 1. Introduction ........................................................................................................ 1 1.1. Overview of the frozen food market ....................................................................... 1 1.2. The nucleation temperature on the freezing curve ................................................. 2 1.3. Current food freezing technologies ......................................................................... 4 1.4. Control of nucleation. Innovative technologies ....................................................... 5 1.4.1. The action of ultrasound and high pressure. ..................................................................... 5 1.4.2. The action of electromagnetic fields .................................................................................. 6 1.4.2.1. State of the art ............................................................................................................... 6 1.4.2.2. Electromagnetism and EM freezing ............................................................................. 11 1.4.2.3. The water molecule ..................................................................................................... 14 1.4.2.4. Effects of magnetic fields on water ............................................................................. 16 1.4.3. The ice produced by a process and its resulting thermal conductivity ............................ 19 1.4.4. Electromagnetic field modelling in food .......................................................................... 20 1.4.5. Modeling freezing processes based on heat extraction rate. .......................................... 22 1.4.6. Modeling nucleation‐controlling freezing processes ....................................................... 22 1.5. Magnetic field freezing at laboratory scale. .......................................................... 23 1.6. Magnetic field freezing at industrial scale ............................................................. 24 1.6.1. Patents ............................................................................................................................. 24 1.7. The lack of scientific research, motivation and objectives of this doctoral thesis .. 28 2. Materials and Methods ....................................................................................... 1 2.1. Description of the equipment ............................................................................... 37 2.1.1. Determination of electromagnetic and thermal parameters on the electromagnetic freezers. 37 2.1.2. The commercial equipment ............................................................................................. 38 2.1.3. The static magnetic field generator ................................................................................. 40 2.1.4. The iron core oscillating magnetic field generator .......................................................... 41 2.1.5. The air core OMF generator of electromagnetic field for wide range low frequencies. .. 43 2.1.5.1. Motivation of the design.............................................................................................. 43 2.1.5.2. Design of the inductor of electromagnetic field for a wide range of low frequencies 49 2.1.5.3. Setting in motion the OMF air core freezing system ................................................... 56 2.1.5.4. Initial prototyping of the inverter for EM field in a wide range of low frequencies .... 57 2.1.5.5. Process of adaptation of the initial inverter to achieve sinusoidal magnetic fields suitable for electromagnetic freezing of foods ............................................................................. 68 iii 2.1.5.5.1. Minimization of the power losses in the switches of the inverter for electromagnetic freezing of foods ............................................................................................ 78 2.1.5.5.2. Selection of input and resonant capacitors ........................................................... 81 2.1.5.5.3. Simulation and quality factor of the square wave method ................................... 85 2.1.5.5.4. Implementation of the control algorithms ............................................................ 86 2.1.5.5.5. Optimization of the PCB design ............................................................................. 90 2.1.6. Model Food ...................................................................................................................... 93 2.1.7. The nanoparticles dispersion ........................................................................................... 94 2.1.7.1. The nanoparticles characterization ............................................................................. 95 2.1.7.2. Freezing nanoparticles experiments ............................................................................ 96 2.1.8. Crab sticks ........................................................................................................................ 96 2.1.9. Pork loin ........................................................................................................................... 97 2.1.10. Magnetic iron solutions, in vivo and in vitro experiments ............................................... 98 2.1.10.1. Magnetic iron solution ............................................................................................ 98 2.1.10.2. In vitro experiments ................................................................................................ 98 2.1.10.3. In vivo experiments ................................................................................................. 98 2.1.10.3.1. Viability of Anisakis .............................................................................................. 99 2.2. Thermophysical properties and Analytical determinations ................................... 99 2.2.1. The freezing curve parameters ........................................................................................ 99 2.2.2. Thermal conductivity of ice ............................................................................................ 102 2.2.2.1. Ice prepared at different freezing rates ..................................................................... 102 2.2.2.2. Ice prepared from aerated and non‐aerated water .................................................. 102 2.2.2.3. Ice prepared in the presence of a magnetic field ...................................................... 103 2.2.3. Quality parameters in food and bio‐samples ................................................................. 103 2.2.3.1. Drip loss ..................................................................................................................... 103 2.2.3.2. Water‐Holding Capacity ............................................................................................. 104 2.2.3.3. Texture analysis ......................................................................................................... 104 2.2.3.4. Color analysis ............................................................................................................. 105 2.3. Mathematical equations governing the laboratory freezer assisted by a SMF generator ...................................................................................................................... 105 2.4. Mathematical equations governing the laboratory freezers assisted by an iron core and by a commercial inductor coil OMF generators ....................................................... 107 2.5. Modeling of the MF freezers ............................................................................... 108 2.6. Statistical analysis .............................................................................................. 109 3. Results ................................................................................................................. 1 3.1. Effects of SMF generator in the freezing of water and solutions of NaCl ............. 113 3.1.1. Modeling of the laboratory freezer assisted by a SMF generator ................................. 113 3.1.2. Evaluation of the modeling and the analytical solutions for the laboratory freezer assisted by a SMF generator ............................................................................................................ 118 3.1.3. Effect of SMFs on water freezing ................................................................................... 120 3.1.4. Effect of SMFs on freezing of 0.9% NaCl solutions ......................................................... 127 3.2. Effects of an