Cooking without heat

[Dr. Diaphanous]

Cooking is the use of heat to kill microbes and denature/degrade/reshape proteins and other molecules in food, and affect other properties such as moisture content. This destroys toxic compounds and makes the food more palatable and digestible.

Could this be done without heat? Surely there are other ways to affect molecules in a similar way? For example radiation, acids*, ionic compounds**, alkalis, toxic heavy metals (disregarding consumer survivability of course), extreme pressure, electric currents, enzymes, decay. Would any of these work?

Examples I could think of:
*pickling?
**salting

[screen317]

"Acid cooking" has been done "successfully" with citric acid from lemons-- at least, none of us got sick when we ate our "cooked" meat from an experiment 8 years ago..

[Sizik]

Lutefisk is fish that has been soaked in lye, but it is cooked prior to eating.

Most cheese is made with rennet, which is a mixture enzymes that comes from mammal stomachs.

Many types of food (and drink) are fermented, which is just controlled decay.

Microwaves are technically radiation.

[Xenomortis]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

[Tass]

Yes, someone subjected chicken meat to huge pressures, causing denaturation of proteins and killing of germs. The meat became white and looked cooked and was apparently quite tasty. However it is to expensive for commercialization.

[gmalivuk]

"Acid cooking" has been done "successfully" with citric acid from lemons-- at least, none of us got sick when we ate our "cooked" meat from an experiment 8 years ago..

It's also been done successfully for ceviche for quite a lot longer.

[dudiobugtron]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

Doesn't pressurisation just do the same thing?

[Tass]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

Doesn't pressurisation just do the same thing?

Yes it does. And someone at my university did it with good results (at 8 kilobar). I don't have time to look for an English reference since I have to fly tomorrow.

[sardia]

Isn't pressure and heat two sides of the same coin?
But yea, I was thinking ceviche as well. Maybe honey? Are you trying to prepare foods, kill microbes, or denature proteins?

[dudiobugtron]

I wonder if you could use freezing to achieve a similar result? Obviously you could kill many microbes with it (and affect moisture content?), but could you freeze something enough to affect the proteins?

[Goemon]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

Doesn't pressurisation just do the same thing?

How much temperature rise would one expect from pressurizing a (mostly) solid? The amount of work done (pressure * change in volume) couldn't be enough to "cook" meat?

[qetzal]

Just freezing won't do much to denature proteins, but repeatedly freezing and thawing will. Though that mainly comes up for purified proteins in solution. I'm not sure how much it would affect proteins in something like a piece of chicken breast.

Other ways to denature proteins in a lab include ionic detergents (e.g. sodium dodecyl sulfate - SDS), and concentrated chaotropic salts (e.g. urea or guanidine hydrochloride). Again, I don't know how well any of those would work on a chicken tender, and I wouldn't care to eat meat soaked in any of those anyway.

[Xenomortis]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

Doesn't pressurisation just do the same thing?

How much temperature rise would one expect from pressurizing a (mostly) solid? The amount of work done (pressure * change in volume) couldn't be enough to "cook" meat?

You heat the gas surrounding it (air).
Alternatively, consider the work done when deforming solid bodies (although I don't think this is very suitable as a means of heating food).

[screen317]

How much temperature rise would one expect from pressurizing a (mostly) solid? The amount of work done (pressure * change in volume) couldn't be enough to "cook" meat?

Meat is squishy though!

[poxic]

It's also mostly water, which doesn't compress easily (~1,000 atmospheres to compress by 10% according to Yahoo Answers). Not sure how that would affect things.

[thoughtfully]

I wouldn't care to eat meat soaked in any of those anyway.

At least you didn't mention lye. Not that I would ever touch the stuff either, but it's on the table a few times a year for those in my family with appropriately inclined tastes.

[p1t1o]

What about dehydration? Removing all of the water from a food (with whatever method you like) will denature proteins and kill bacteria, or at least deny them a favourable environment. Isn't this what jerky/billtong is?

[Xanthir]

Jerky also uses heavy salting to kill and preserve. Just drying by itself definitely helps, but isn't enough to finish the job.

[idobox]

Cooking doesn't necessarily mean killing microbes, lots of stuff can survive being boiled, and that's why you get sick if you eat old meat, even cooked. On a side note, I love microbes to be alive in my cheese, wine, beer, yogurt, fresh fruits.
And proteins aren't the only things that are affected. Sugar being transformed into caramel is important in a few recipes, include grilling meat IIRC.

There is also a trend in high end restaurants to cook stuff with liquid nitrogen. I am not sure how it works though.

[PM 2Ring]

Yeah, apart from the issues of killing microbes and denaturing proteins, a lot of foods would be pretty boring without the Maillard reaction and carmelization.

[sardia]

Cooking doesn't necessarily mean killing microbes, lots of stuff can survive being boiled, and that's why you get sick if you eat old meat, even cooked. On a side note, I love microbes to be alive in my cheese, wine, beer, yogurt, fresh fruits.
And proteins aren't the only things that are affected. Sugar being transformed into caramel is important in a few recipes, include grilling meat IIRC.

There is also a trend in high end restaurants to cook stuff with liquid nitrogen. I am not sure how it works though.

Modernist Cuisine would answer that. It's a great read if you like an explanations for why cooks do what they do. Just what I learned about brining and cooking steak has changed my view how to cook meat. I'm almost done with volume 2 and 3. I have no idea if I'll ever get to volume 1, 4 and 5.

[Quizatzhaderac]

Soaking in alcohol is another one.

I wouldn't count dehydration as the methods stringent enough to kill bacteria (not just limit growth) involve heating.

[You, sir, name?]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

If I remember correctly, X-rays and β-beams are used for sterilizing materials through other means than heat.

[Xenomortis]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

If I remember correctly, X-rays and β-beams are used for sterilizing materials through other means than heat.

Neither of those are produced in large amounts by kitchen microwaves though.

[You, sir, name?]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

If I remember correctly, X-rays and β-beams are used for sterilizing materials through other means than heat.

Neither of those are produced in large amounts by kitchen microwaves though.

No, I was thinking more along the lines of industrial sterilizer.

[Xenomortis]

More importantly, gamma rays aren't microwaves.
And neither are beta particles.

[You, sir, name?]

More importantly, gamma rays aren't microwaves.
And neither are beta particles.

I was merely giving an example of cooking without heat with radiation.

[dudiobugtron]

I was merely giving an example of cooking without heat with radiation.

I think the confusion was that in the bit you quoted, Xenomortis was referring specifically to microwaves.

[thoughtfully]

Cooking doesn't necessarily mean killing microbes, lots of stuff can survive being boiled, and that's why you get sick if you eat old meat, even cooked.

I'm pretty sure spoiled meat makes you sick because it's full of the products of bacterial growth, not because of the bacteria. It's the same bacteria, after all, that are killed by cooking when it's still fresh.

[mercutio_stencil]

The last is still heating; the radiation doesn't do much other than serve as a means of heating.

Doesn't pressurisation just do the same thing?

Yes it does. And someone at my university did it with good results (at 8 kilobar). I don't have time to look for an English reference since I have to fly tomorrow.

There are a few commercial companies out there using pressure as a method of reducing the bacterial count of their products, although they have unfortunately chosen to call it, 'Fresherized.' Although they use a measly 6 kbar. It only works on things you don't mind being somewhat squished, apparently avocado works great.

[poxic]

If they treat the avocados before they ripen, they'll come out fine. Unripe avocados are somewhere near diamond on a hardness scale.