MEAT COOKING 201

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urbangriller
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MEAT COOKING 201

Post by urbangriller »

MEAT COOKING 201
A Practical Science Lesson

Cooking is a physical process which effects a chemical and physiological change in foods.

We cook foods for a number of reasons, generally to make them more pleasing and appetising to eat, but in some cases foods are cooked to preserve them and in other cases, to make the food safe to eat. Meats are cooked to enhance flavour and to tenderiser, flavour enhancement is largely a process of "caramelisation" otherwise known as the Maillard reaction. The Maillard reaction occurs at 150° C (300° F) and in simple terms the caramelised flavours are the product of the carbohydrates reacting with amino acids as the surface of the food dries.

We know that we can predict the "doneness" (hate that word) of meats by the internal temperature they are cooked to, but let’s explore the process a little deeper and look at what is happening.

At 66° C (151° F) the liquid in a cell expands to the point where the cell wall bursts and the liquid is lost to the surrounding void (it is no accident that medium well done beef begins at an internal temperature of 66° C (151° F)). Add to this the knowledge that the meat fibres contract (or tense up) when heated. If we have heated the meat to the point of cellular destruction and we cut into it when the fibres are still tense we effectively allow the juices to be squeezed out. For meats cooked above 66° C (151° F) it is essential to employ a resting period to allow the fibres to relax and draw back the juices within their structure. Wrap the meat in foil and wrap in a towel or two for at least 15 minutes (this is enough time to cook the veggies), some chefs rest for the equivalent time as the cooking itself. During this process the juices will redistribute and the “cook” will be more even, when cut the meat will be a more even colour all the way through, the redness of medium rare beef will disappear and you will be able to serve it to your more squeamish guests with nothing but compliments for how juicy your roast is!

Cheaper cuts of meat are generally tougher, that is, they contain a greater percentage of connective tissue. Connective tissue breaks down with the application of temperature (70-80° C, 160-180° F,) over time; the problem is that these temperatures are above the temperature at which meat loses its liquid as a result of the deformation of the cellular structure.

So, the challenge with tougher meats is to cook them so they become tender without losing flavours, moisture and texture, rather than cooking to a certain temperature, these cuts are cooked at low temperatures for a greater length of time, until tender. This is the process used by crock-pots.

What we are looking for in this process of slow, low temperature cooking, is for the collagen in the connective tissue to be broken down into gelatine and an the gelatine to absorb, or "hold" some of the juices released from the cells of the meat. Fortunately there is a trick we can employ, if meat is brought to a temperature of 50° C (120° F) and held there for a few hours the collagen will artificially "age" and begin to break down, softening the structure of the meat as it convents to gelatine; slow cooking also helps retain the colour of meat.

All meat contains protein, if we look at protein under a microscope it is a long atomic string which has folded and twisted over to from a structure not unlike steel wool. Each cell in a piece of meat is full of these protein structures floating in a particulate (Read: Salty) liquid. The protein structures contain more particulate liquid which is trapped inside the tightly wound structures, if you can imagine those "steel wool" structures stacked on top of each other you get on idea of how springy or chewy this would be. So when cooking food we endeavour to break or unwind (denature) these structures to promote tenderness and to release the juices trapped inside.

Proteins are denatured by heat and chemical reactions precipitated by enzymes. As far as heat is concerned, proteins begin to denature at 62° C (140-180° F).

And that brings us to enzymes; enzymes promote chemical reactions, enzymes are also part of the protein family. At low temperatures (refrigerator) enzymes become almost dormant, for every 10° C, 20 F increase in temperature enzyme reactions increase effectively double, until the denaturing (of the enzyme) occurs. In the case of meat, gentle heating over an extended time can maximise the enzymic reactions responsible for tenderising and flavour development.

Enzymes can also be artificially introduced to promote the denaturing, Kiwi Fruit contains a protein-dissolving enzyme actinidin, (papaya contains a similar enzyme: papain), which is commercially useful as a meat tenderizer.

In vegetables we want to go through this heating phase quickly to prevent the enzymes the and enzymic reactions caused from discolouring the food, in vegetables it is the cellulose we are breaking down, but the principle is the same.

Bacteria:
Chicken and Pork contain particularly nasty bacteria which can develop into strains responsible for typhoid, diarrhoea and other nasty inconveniences, which is why we cook them to higher temperature than other meats.

Bacteria generally reside in the fat and connective tissue, which means that lean meat is less of a problem than" fattier" cuts, chicken breast is less of a problem than thighs and can be cooked to a lower temperature. E-coli and his friend are destroyed when all parts of the food have been cooked to a temperature of 70° C (158° F).
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Davo
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Post by Davo »

Thankyou Urbangriller for sharing that info with us. I found this to be a very interesting read. It helps to be a bit more educated about the foods we cook & eat.
I'll be looking forward to your next post.

cheers

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paulr
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Post by paulr »

Good article...thanks :D
Hence I slow cook my ribs and for 4 hours and raise the temp for the last hour and a half!
Have yet to do a brisket (my butcher is willing to do a nice piece for me) and do a 12 hour cook....
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https://lifesafeast.com.au/cookingclass ... criptions/ - great cooking classes
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Bentley
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Re: MEAT COOKING 201

Post by Bentley »

Good read!
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bodgy
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Re: MEAT COOKING 201

Post by bodgy »

bellabrownn wrote:Such a Great Article.....)
I just want to say that you must have to boiled meat with the little salt that will make meat crispy and testy...just try it...it's my personal opinion.
ahh Mr Griller, have you ever broiled to meat 501?
urbangriller
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Re: MEAT COOKING 201

Post by urbangriller »

Hmmmm, I think Bella is talking about broiling (cook by direct heat) after seasoning with salt to help the grill marks along?

And so: HELL YES! All the Time!

Ha!
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imarty
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Re: MEAT COOKING 201

Post by imarty »

Great post Chris, very interesting but I have to take issue regarding your pork comment containing nasty bacteria.
Pork is no less safe than beef or lamb due to the extremely high farming and processing standards present in Australia. It does not need to be cooked through and is safe to eat rare.
Not sure if you meant trichinosis which is a parasite and has not been present in Australia for over 40 years.
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urbangriller
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Re: MEAT COOKING 201

Post by urbangriller »

imarty wrote:Great post Chris, very interesting but I have to take issue regarding your pork comment containing nasty bacteria.
Pork is no less safe than beef or lamb due to the extremely high farming and processing standards present in Australia. It does not need to be cooked through and is safe to eat rare.
Not sure if you meant trichinosis which is a parasite and has not been present in Australia for over 40 years.
Cool Marty,

I'll make an edit, been asking heaps of people, for years with nobody game enough to give me a definitive answer!

Thanks

Chris
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imarty
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Re: MEAT COOKING 201

Post by imarty »

Thanks Chris. If there's anything you're not sure about on the raw side of things, if I can't answer it I'll be happy to find out for you and there's a hell of a lot that you know more about than me anyway!
There was heaps in this post that I learnt.
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urbangriller
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Re: MEAT COOKING 201

Post by urbangriller »

Thanks Marty.

I've got to do a re-write (this weekend....cross fingers) to include that stuff about collagen breaking down into gellatine....and a few other things.

Stand By!

Chris
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sosman
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Re: MEAT COOKING 201

Post by sosman »

Chris,

I was struggling with this and wondered if you could explain it in the next instalment Image:

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From the book "Cooking for Geeks" (http://www.cookingforgeeks.com/). Actually its a very cool book. I found out that myosin in meat (not fish) begins to denature at 50 C and actin denatures between 66-73 C. Better still he explains this in the context of your really juicy steak.
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urbangriller
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Re: MEAT COOKING 201

Post by urbangriller »

Hmmmmm, well it seems fairly clear:

The Temperature of the final cook is a result of the application of heat energy over a time period and the rate of heat takeup at any point in the time curve is proportional to the amount of heat available but is inversley restricted by the amount of heat energy already taken up and stored..........Haven't you got an App for your phone that calculates this for you? :lol: :lol:


Seriously good read though! 8)

Chris
Last edited by urbangriller on Sun Apr 03, 2011 3:18 pm, edited 1 time in total.
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Davo
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Re: MEAT COOKING 201

Post by Davo »

I knew there was a reason I didn't like algebra at school :oops: :roll:
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Re: MEAT COOKING 201

Post by Buccaneer »

Extremely pleased we have members getting into it so deeply.
Maybe teach this old bull a thing or two.
:oops:
sosman
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Re: MEAT COOKING 201

Post by sosman »

Buccaneer wrote:Extremely pleased we have members getting into it so deeply.
Maybe teach this old bull a thing or two.
:oops:
Well it doesn't take into account "the stall" so its bloody useless.
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