‘Supercool’ fruits

Soojin Jun of the University of Hawaiʻi at Mānoa’s College of Tropical Agriculture and Human Resources recently received a grant to study a high-tech new way to preserve food for storage and shipping. Jun, an associate professor in Department of Human Nutrition, Food and Animal Sciences, proposed a research project to address the loss of quality in food items due to freezing and thawing during storage and transportation, which leads to waste and a decrease in economic value. Jun and Co-Principal Investigator Peter Berkelman, an associate professor in the UH Mānoa College of Engineering, received a three-year, $500,000 Improving Food Quality and Value grant through the USDA’s National Institute of Food and Agriculture.

During the freezing process, water crystallization can result in irreversible damage to tissue structures resulting in damage to a variety of foods. In contrast, Jun’s project aims to preserve food’s original freshness by controlling the supercooling and ice crystallization of water using combined pulsed electric and magnetic fields. “Supercooling” refers to the process by which water temperature drops below the freezing point, but there is no transition to ice.

A portion of the grant includes work on a prototype freezer equipped with pulsed electric field and oscillating magnetic field generators, designed and fabricated in the Department of Human Nutrition, Food and Animal Sciences lab. This proposed technology has the potential to ensure food quality and freshness during storage, which would have an enormous impact on the food industry. It would specifically benefit Hawaiʻi and the Pacific Basin by ensuring food security and sustainability, as well as provide new export opportunities for local farms and entrepreneurs.

Beyond the food industry, the supercooling technology has exciting possibilities for use in medical applications such as organ and tissue transplantation.

Not only is quality improved, but the length of storage can also be extended. “As long as the developed freezing technology is applied, the implemented supercooling stage of food materials, i.e., meat, fruits, fish, etc., can be longer, we anticipate,” Jun said. “We plan to investigate the max extension of the supercooling stage and its stability as well.”

—A UH Mānoa news release