The USDA Agricultural Research Service (ARS) and scientists at the University of California, Berkeley have conducted research that switching to a new method of freezing fruits and vegetables can make food safer and better, as well as save energy and reduce carbon emissions.

The isochoric freezing method consists of storing food in an airtight, rigid container, usually made of hard plastic or metal, completely filled with a liquid such as water. Unlike conventional freezing, which exposes fruits and vegetables to air and freezes to a solid in temperatures below freezing Celsius, isochoric freezing preserves food without turning it into solid ice. As long as the food is immersed in water, it is protected from ice crystallization and the structure of the fruit is not disturbed.

“A complete switch to isochoric freezing of food worldwide could reduce energy consumption by 6.5 billion kilowatt-hours each year, while simultaneously reducing the carbon emissions associated with generating this energy by 4.6 billion kg. The reduction comes from not having to freeze food to a completely solid state, which requires a huge amount of energy, and there is no need to resort to energy-intensive refrigerator storage protocols such as blast freezing to avoid ice crystals. Energy savings can be achieved without any significant changes to existing equipment and infrastructure for frozen food production if producers agree to adopt the new concept,” said ARS food researcher Cristina Bilbao-Sainz.

Isochoric freezing also allows for better storage of fresh produce such as tomatoes, cherries and potatoes. Another advantage of isochoric freezing is that it kills microbial contamination during processing.

“The entire frozen food chain can use isochoric freezing, from producers to processors, wholesalers and retailers. Even after the customer brings the product home, it will remain in his refrigerator. With all the many benefits, if this innovative concept catches on, it could be the next revolution in freezing food,” added WRRC Director Tara McHugh, co-director of the study.

Matthew Powell-Palm, a mechanical engineer at the University of California at Berkeley, one of the lead authors of the study, noted that this method of freezing can be used not only in the food industry, but also in medicine, biology and even for space travel.

EastFruit