A Fresh Look at Frozen Foods

Frozen foods are enjoying a resurgence in popularity, as a new generation discovers the nutrition and convenience available in the freezer aisle. And new advances in freezing technologies are unlocking new benefits in frozen foods.

Different Food Freezing Techniques

If soda in an aluminium can is left too long in a freezer, the can will burst – because the freezing air and liquid inside the can expand in volume. If the same amount of soda is placed in the same freezer, but in a rigid container with no air, a different result occurs. Part of the liquid freezes, so pressure increases in the container, but the volume stays the same because the freezing liquid can’t expand. The pressure prevents most of the soda from freezing, and there’s no bursting.

There’s a name for both these freezing processes. The first, isobaric freezing, is the conventional type, familiar in kitchens and grocery stores. This type of freezing reduces the temperature and volume of the food, essentially turning it to ice. In scientific terms, the pressure stays constant, but temperature and volume change. 

The second type is isochoric freezing. Food is immersed in a liquid inside a rigid container, which is then chilled. The container prevents expansion, so volume remains constant; but as the temperature goes down, the pressure inside the container increases. Isochoric freezing may be about to revolutionize the frozen food industry.

Origins of Isochoric Freezing

Boris Rubinsky and his team at University of California, Berkeley developed the process to freeze cells, tissues and organs for transplant. This freezing technique preserves biological materials. No ice crystals form in the tissues, so a frozen organ or tissue is revivable and functional. Rubinsky saw that this technology has other potential applications, among them the frozen food industry. In 2017, he began working with the USDA to demonstrate that potential.

Rubinsky’s work shows that isochoric freezing preserves even fragile foods like tomatoes and berries in an almost completely fresh condition. That’s because cell walls are not broken by ice crystals. Also, this preservation technique allows food to be preserved in the freezer and removed ready to prepare – no thawing needed.

The Global Impact of Frozen Foods

The value of the frozen food market globally was $250 billion in 2015, expected to reach $404.8 billion by 2027. The biggest expense in the industry is the energy needed to keep refrigeration units operating. The environmental cost of the technology is mostly due to CO2 emissions from generating electricity. There are also some global warming effects due to leaked fluorocarbons.

Isochoric freezing offers several exciting possibilities for extending the efficiencies and reducing the economic and environmental costs of refrigeration. Some potential benefits of this new technology include:

  • Isochoric freezing will work with existing refrigerators. Refrigeration units along the whole product chain, from the grower to processors, shippers, wholesalers, retailers and home kitchens won’t have to be modified.
  • The new tech uses 70% less energy, because food won’t be frozen solid, as it is now – only about 10% of the liquid in the container freezes; just enough to raise pressure inside the container. The energy savings could amount to 4.59 billion kg in carbon emissions, the equivalent of 1 million cars.
  • The combination of cold and pressure in isochoric freezing destroys microbes; traditional isobaric freezing inhibits microbes, but doesn’t kill them.
  • Isochoric freezing extends the shelf life of beverages such as juice and milk.
  • The liquid solution surrounding the food can be fortified with compounds to add flavor and improve nutrition.
  • Temperature fluctuations that occur during shipping and storage are greatly reduced, so spoiling and food waste also be cut.

Next Steps in Isochoric Freezing

Research is underway to develop rigid, food-safe, cost-effective containers that will work for this process. Containers used in experiments so far have been made of thick-walled stainless steel cylinders, but mass-produced containers could be made from carbon fiber composites or phenolic resins.

Isochoric freezing is not simply applicable to the food and beverage industries. It also has possible applications in medicine, life sciences, and even for space travel.

The future of food is unfolding in so many exciting directions. Every day, innovators are discovering new ways to improve food flavor and quality, and reduce the environmental impact. If you want to be part of the future of food or your company needs innovators, contact grapefrute today!