DESIGN, APPLICATION, AND STABILITY OF SUPERCOOLED STATES IN FOOD PRESERVED USING ENGINEERED ELECTRIC AND MAGNETIC FIELDS
Date
2024
Authors
Contributor
Advisor
Department
Instructor
Depositor
Speaker
Researcher
Consultant
Interviewer
Narrator
Transcriber
Annotator
Journal Title
Journal ISSN
Volume Title
Publisher
Volume
Number/Issue
Starting Page
Ending Page
Alternative Title
Abstract
Supercooling is the process of cooling a liquid or food below its freezing point without the formation of ice crystals, which prevents cellular damage and preserves the texture, moisture content, and overall freshness. Lowering the temperature beyond conventional refrigeration it slows microbial growth and enzymatic reactions, leading to an extended shelf life. While it offers significant advantages over conventional preservation technologies such as refrigeration and freezing, achieving and maintaining the supercooled state poses challenges. The inherent thermodynamic instability of the supercooled state presents several practical challenges. Recent advancements suggest that using external AEF and OMF could achieve the supercooled states. The primary objectives were to design and fabricate AEF and OMF modules for food supercooling, to analyze the preservative effects on high-value seafood such as tuna, and to validate the supercooling stability under mechanical and thermal stresses.A core-based electromagnet was designed and optimized through numerical simulations using COMSOL Multiphysics to address challenges. The electromagnet was intended to generate a uniform OMF for supercooling applications, with numerical simulations to evaluate both its magnetic and thermal performance. Experimental validation showed strong agreement with the simulations the system can effectively achieve the desired magnetic field strength while managing heat generation, which is crucial for maintaining supercooled states in practical food preservation applications. Experimental validation showed a high correlation with simulation results, with only a 4.04% error in magnetic flux density and 3.4% in thermal behavior, demonstrating the effectiveness of the developed modeling approach in designing supercooling systems.
Seafood is highly perishable, and spoilage begins immediately after harvesting due to the production of various metabolites. Freezing, a conventional long-term preservation method, often leads to quality degradation caused by ice crystallization. Supercooling has emerged as a promising technique to prevent ice formation and reduce quality degradation. Tuna fillets were supercooled at -3.5°C using optimized AEF and OMF. Quality factors, including drip loss, color, microbial load, texture, and total volatile basic nitrogen (TVB-N), were evaluated and compared with refrigerated, frozen-thawed, and supercooled samples during the storage period (10 days). Results indicated that supercooled tuna samples exhibited lower TVB-N values than those stored under refrigeration while maintaining aerobic plate counts that remained stable from 1 to 7 days. Supercooling also preserved the textural integrity of the fillets and significantly reduced drip loss compared to frozen-thawed samples.
The stability of supercooled states in food was tested under external stresses, such as mechanical vibrations and temperature fluctuations, to simulate real-world cold chain conditions. Using OMF at specific working frequencies, the stability of supercooled agar gel samples was evaluated. OMF-treated samples demonstrated significantly higher resistance to ice nucleation compared to untreated controls, with a 95% probability of maintaining supercooling under orbital motions at 200 RPM, while untreated samples showed only a 10% success rate. However, vertical vibrations exceeding a peak force of 0.6 g triggered ice nucleation, indicating the need for further optimization to improve robustness against such disturbances.
A scaled-up supercooling system (30 L volume capacity) was developed and tested for larger food samples, addressing the limitations of previous systems in handling small sample sizes. The prototype system, designed to maintain stable supercooling conditions for larger volumes of food, successfully extended the supercooled state of packaged tuna fillets.
Description
Keywords
Agriculture engineering, Food science, Bioengineering, Food preservation, Magnetic field, Scale up, Supercooling, Supercooling stability
Citation
Extent
212 pages
Format
Geographic Location
Time Period
Related To
Related To (URI)
Table of Contents
Rights
All UHM dissertations and theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission from the copyright owner.
Rights Holder
Local Contexts
Email libraryada-l@lists.hawaii.edu if you need this content in ADA-compliant format.