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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: 5, Interesting) by Anonymous Coward on Sunday September 05 2021, @12:18AM (5 children)
You're not entirely wrong. I did some reading, and here's what I gleaned:
a) take a pressure vessel
b) fill it with your liquid medium (arguendo, water)
c) put your food into the liquid medium
d) make damn sure there's no air bubble because air will screw with things because of its compressibility
e) close your pressure vessel
f) drop the whole thing to freezing temperatures
g) this doesn't actually freeze all the water in it (Some freezes to ice, some doesn't.)
h) when you open the pressure vessel and remove your goodies, they're less freezer burned
I am very sceptical. I could be convinced, but I have serious questions. I am not sceptical about the physics; that part entirely checks out. The behaviour of water in the temperature/pressure envelope under discussion is quite well understood. The claim that this does less damage to food than conventional freezing, but also kills microorganisms on some notable level makes me suspicious. But that's the least of it.
What makes me really suspicious is the economics. Pressure vessels up to this task are not particularly light (shipping costs!), not particularly easy to get right in terms of a long, active service life, not particularly easy to purge of bubbles without additional steps, and will need to be in some freezing cold context anyway if you're not incorporating your refrigeration system into the vessels (very expensive) and will have to be repurged every time you opened a vessel to pull out some cherry tomatoes (or whatever). Compared to a pack of steak wrapped in butcher's paper, it's a shitshow of a process. To make it justifiable both the process, the cost of construction and distribution of the vessels and the transport of the additional vessels and liquid media would have to overcome the costs of refrigeration. This is ... let's call it a logistical challenge.
If I were to start a food preservation scheme, I would look into pickling solutions (seal and shelf stable!) canning solutions (one major energy input, then shelf stable for decades), desiccation solutions or some combination of the above. While I wouldn't describe this as exactly a solution looking for a problem, it looks as if it doesn't solve problems that I have, while it introduces new problems that I don't want.
(Score: 4, Interesting) by wisnoskij on Sunday September 05 2021, @03:19AM (1 child)
I guess these would be quite large containers? The entire point here seems to be to save energy on not having to do the ice phase change. But their is not a tremendous amount of energy in the ice phase change (at least relative to vapor), so it would be pretty important to only freeze the smallest percentage of ice as possible. Additionally, you are adding mass as you add water, so the water would need to be a tiny percentage of the total mass or cooling it down to liquid 0 would cost more than the phase change savings.
Then not only do we have more mass for transport and special expensive packaging. But it is also less shelf stable as we have put less cold energy into it. And being in the food industry I can say that frozen food is often shipped with inadequate or non existent cooling, with the hope that it a big enough pile of it will stave off melting long enough to get to the destination.
This seems like more of a high end specialty process you might use on the most expensive cuts of meat to ship world wide instead of just regional. People are probably having Kobe beef jetted into their snobby restaurants. With pressurized 0 degree chambers this beef might be put on slow cargo ships at significantly less cost and arrive at the destination months latter.
(Score: 0) by Anonymous Coward on Sunday September 05 2021, @04:22PM
Yeah, it would be cheaper, easier, arguably safer to just have a dry ice brick system inside your cool transit system. Sure, there's freezer burn, but we already know about and live with that.
Or, you know, just use less energy-hungry food storage systems.
(Score: 2) by Gaaark on Sunday September 05 2021, @02:11PM (2 children)
Yeah, the pressure vessels would not be light, plus the water which is heavy, plus the food product itself? TCOS!(Total Cost Of Shipping)
--- Please remind me if I haven't been civil to you: I'm channeling MDC. ---Gaaark 2.0 ---
(Score: 0) by Anonymous Coward on Sunday September 05 2021, @06:11PM (1 child)
A shock wave could momentarily change the pressure in the liquid (and the stuff to be preserved), so what would happen if say the container was dropped and hit the ground? Or someone smacked it with a trolley/hard object etc.
This suggests it's more stable but would it really be stable enough in practice with the sort of containers they'll be using? https://aip.scitation.org/doi/10.1063/1.5145334 [scitation.org]
(Score: 0) by Anonymous Coward on Sunday September 05 2021, @08:46PM
Assuming that any such shocks would be in tolerance for the container, slightly higher pressure waves might temporarily destabilise some ice that had formed, but in reality it'd be over too soon to have any substantial effect.
Seal breaches would be much more fatal, because all you need is a little, slow seepage to screw the whole system.