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New food freezing concept improves quality, increases safety and cuts energy use:
"A complete change over to this new method of food freezing worldwide could cut energy use by as much as 6.5 billion kilowatt-hours each year while reducing the carbon emissions that go along with generating that power by 4.6 billion kg, the equivalent of removing roughly one million cars from roads," said ARS research food technologist Cristina Bilbao-Sainz. She is with the Healthy Processed Foods Research Unit, part of ARS's Western Regional Research Center (WRRC) in Albany.
"These savings could be achieved without requiring any significant changes in current frozen food manufacturing equipment and infrastructure, if food manufacturers adopt this concept," Bilbao-Sainz added.
The new freezing method, called isochoric freezing, works by storing foods in a sealed, rigid container -- typically made of hard plastic or metal -- completely filled with a liquid such as water. Unlike conventional freezing in which the food is exposed to the air and freezes solid at temperatures below 32 degrees F, isochoric freezing preserves food without turning it to solid ice.
As long as the food stays immersed in the liquid portion, it is protected from ice crystallization, which is the main threat to food quality.
[...] Another benefit of isochoric freezing is that it also kills microbial contaminants during processing.
Journal Reference:
Analysis of global energy savings in the frozen food industry made possible by transitioning from conventional isobaric freezing to isochoric freezing, Renewable and Sustainable Energy Reviews (DOI: 10.1016/j.rser.2021.111621)
(Score: 3, Interesting) by bzipitidoo on Sunday September 05 2021, @01:32AM (1 child)
Sounds like the food is mixed into the isochoric medium? Or is there some membrane keeping the food separate from the liquid?
I also wondered if this was supercooling. No, seems isochoric cooling is not the same as nor uses supercooling.
Another thing that puzzles me is the pressure. Reason for the rigid container is pressurization. Increasing the pressure rapidly raises the boiling point, but it doesn't budge the freezing point until the pressure gets above approximately 90 atmospheres, then the freezing point actually starts down a little. So maybe that's one thing they're doing, pressurizing so that it will stay liquid even as it gets a little below 0 degrees C.
(Score: 1, Informative) by Anonymous Coward on Sunday September 05 2021, @01:53AM
You have it backwards.
It's pressure rising because of freezing.
Think of all those little H2Os floating around, getting sleepier and sleepier until they want to hook up into a nice ice crystal for the freeze. But there's a problem; their ice crystal formation takes up more space than just liquid slithering over each other. This means that, even as they get colder, the pressure in the vessel rises.
What they're doing is chilling the thing, and they can assess how cold it is in the vessel by the internal pressure. Colder? Higher pressure. What this does is bring it nearer the point where other crystal formations take priority over conventional ice that you or I know in our frozen daiquiris.
The result for the food is that it doesn't freeze (as much) but it's under ferociously high pressure (but because the medium is functionally uniform, it's not crushed). The only real hitch is the high quality pressure vessel that makes a diver's cylinder look like a banker's envelope, or titanium for extra giggles.