Time&Temperature vs energy needed for molecules structure’s changes

cooking-timesciencetemperature

Recently I've read an interesting post about time vs temperature (Time vs. Temperature – What changes what?)

I've been thinking about this problem for a long time.
and I'd like to share an idea..
"A single piece of meal, need certain amount of energy to modify its molecules structure."

Sous vide technique for cooking pork cheeks says (made by a well known Chef):

48h at 65ºC or 24h at 80ºC

This long time is needed to denature the myosin and other internal transformations…and so
For those transformations, we need to give energy to the meat.

So, if we asume, that both temperature/time alternatives, give us the perfect result.

Is it possible to know how much energy is used in each situation? could it be a similar amount of energy?

If this hypothesis is valid, then, we could use that value, to answer two questions:
1.-how many hours will be needed if we cook it at 70ºC?
2.-if we'll cook it for 36h, what should be the temperature than we need to keep?

anyone could help us with the formulas?
thanks a lot!

Best Answer

The hypothesis is somewhat valid. The version which is true is: there is a correlation between the total amount of energy which went into the meat and the degree of doneness. And because the total energy is the rate of energy input multiplied by the time you are adding energy to the system, time and heat are interchangeable to some extent.

However, there is no constant "total amount of energy" which needs to go into the meat. Protein denaturing is a complicated stochastic process. If we were to assume that we have a uniform thin layer of meat and a perfectly uniform heat source parallel to it, we still wouldn't have a constant total amount of energy. It is a bit less noticeable with meat, where preparation methods are limited (*), but in eggs it is easy to observe that the speed at which yolks are heated will have a noticeable difference on the final texture of a custard.

Even if you could get away with a usable range for the "total amount of energy", you could still not predict the time needed by a given piece of meat at a given temperature. We are talking about a complex nonlinear system here. That part is a duplicate of another question, so I will simply post a link to my older answer.

So in the end, there is a very good reason why you should check for doneness instead of try to predict doneness. Or, in the special case of sous vide, use the empirically determined charts somebody else went to all the trouble compiling. Calculating it for yourself is completely impractical.

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