Background

Cold preservation of perishable products and biological materials is necessary in many applications. Extending the shelf-life of food reduces waste and economic loss. Storage of tissue, cells and organs is critical in research, medical procedures, life-saving transplantations and therapies. Many common and familiar methods are used for perishable product storage, such as refrigeration and freezing. Refrigerated food maintains texture, quality, and nutritional value for only a relatively short period of time before spoilage occurs. Freezing allows food to be stored longer, however, it causes irreversible damage to quality, texture, moisture content and nutritional value. Cryopreservation methods may also affect the functional qualities of stored biological specimens. The highly organized structures of tissues are extremely sensitive to freezing and thawing. Furthermore, the use of cryoprotective agents, that are potentially toxic, are required to prevent crystallization and need to be eliminated rapidly. Methods generating extracellular ice formation are known to reduce food quality and damage tissues and organs, therefore, supercooling technology that prevents ice crystal formation provides valuable benefits and broad applications.

Technology Overview

Novel supercooling technology is being developed at the University of Hawaii to maintain quality, freshness, and extend storage time for diverse products, including biological materials. This is achieved through programmed pulsed electric fields (PEF) and oscillating magnetic fields (OMF) that together keep water molecules vibrating even while temperatures are below freezing points. Water within stored specimens is maintained in a stable, supercooled, unfrozen state that inhibits ice crystal formation, preventing resulting damage to cellular structures. Thawing is also not needed. The supercooled product is safely and effectively preserved in a soft, natural state similar to the original, unfrozen material. The technology has been successfully demonstrated with food products (meat, fish, fruits, vegetables), preserving taste, texture and color. New applications are currently being explored, including preservation of biospecimens that serve critical research and healthcare needs.

Further Details

You, Y., Her, J.Y., Shafel, T., Kang, T. and Jun, S. 2020. Supercooling Preservation on Quality of Beef Steak. Journal of Food Engineering 274, 109840 https://doi.org/10.1016/j.jfoodeng.2019.109840

Kang, T., Her, J., Hoptowit, R., Wall, M. M., and Jun, S. 2019. Investigation of the effect of oscillating magnetic field on fresh-cut pineapple and agar gel as a model food during supercooling preservation. Transaction of the ASABE 62(5):1155-1161

Mok, J. H., J. Y. Her, T. Kang, R. Hoptowit, and S. Jun. 2017. Effects of pulsed electric field (PEF) and oscillating magnetic field (OMF) combination technology on the extension of supercooling for chicken breasts. Journal of Food Engineering 196:27–35.

Mok, J. H., W. Choi, S. H. Park, S. H. Lee, and S. J. Jun. 2015. Emerging pulsed electric field (PEF) and static magnetic field (SMF) combination technology for food freezing. International Journal of Refrigeration 50:137–145.

Benefits

For food, prolonged shelf life while maintaining overall quality
- Applicable to food storage
- Non-freezing method; prevents ice crystallization
- Freshness qualities maintained for weeks
- Reduces food waste and associated financial loss
- No thawing required
For biological materials, investigations ongoing into prolonged storage and viability of biological specimens. Objectives include:
- Higher recovery rate of cell, tissue and organ viability
- Minimize cellular and functional damage
- No toxic agents used as in cryopreservation methods
- Eliminates thawing and damage caused by freezing and thawing processes
Energy savings with pulsating field emissions, compared to commercial freezers

Applications

Fresh food preservation
Consumer and commercial food industry storage and transportation
Biopreservation
Numerous other agricultural and biomedical applications

Supercooling Technology for Subzero Non-freezing Preservation of Perishable Foods and Biological Materials

Patents

IP Status

Seeking