Was watching 'Saturday Kitchen' this morning and a guest chef, Cyrus Todiwala, was insistent that for his lamb dish the meat should be marinated for two hours at room temperature before being left in the 'fridge overnight.

Can we create a formula for marinating time?

Say,

h = hours

t = temperature (Celsius)

so h x t = m

m being resulting marination hours. What should m be?

Suppose we should also factor in the size and texture of what we are marinating but the original poser is enough for one day!

If there was a formula it would have to have

A - product being marinated

B - product/s being used to marinate with

C - any special properties of the marinate that may preserve/kill bacteria

D - max and minimum temperature that the products could be safely left at for a given period

E - Age of product and how has it been stored already

F - the required end result of marination

and probably some other bits and bobs...

Lets say you want to add a little flavouring to some delicate fish, you wouldn't want to just put a formula that says leave it for 1 hour and then find the lemon juice has cooked it right though and its falling to bits ..

Nor do you want to leave a piece of meat at 30?C that you are serving rare and have everyone going ill....

etc

Steve

surely marination is about flavour, not preservation? If you want preservation you are talking pickling, nor marination.

I have seen absorption rates of chemicals through the skin, and wonder whether this is useful. The absorption rate depends on two major peoperties of the flavour chemicals. They are molecular weight (and therefore size) and hydrophobicity, or how much the flavour compound dissolves in water or oil.

All flavour chemicals have a molecular weight of less than 300, because we cannot smell chemicals with molecular weights higher than this. Also, most of the flavour chemicals are oil liking, a measure of this is called the Kow, or octanol water partition coefficient. This really means, if you place the same quantity of oil and water in a cup, and add some flavour chamical. and stir to dissolve, some of the chemical will dissolve in the water, and some in the oil. If more dissolves in the water, it is said to be hyrophilic (water liking) or lipophobic (oil hating). If more dissolves in the oil, it is hydrophobic or lipophilic. For flavour chemicals, most like oil about 10 to 100 times more than water, (this is why I say it is important to extract the flavours into oil at the start of cooking).

Now the more lipophilic a chemical is, the faster it is absorbed by the skin, up to a point. One assumes this is also so for meat muscle, but other things probaly play a role in the determination of flavout absorption.

Of the equations I have seen and used (I don't have them to hand) they suggest the time is in hours rather than minutes, and 24 hours is a resonable time to aim for. Water based marinades will be less, but so will the penetration of the substances, and the flavour chemicals may well only aDsorb (stick) to the outside of the meat muscle, rather aBsorb into it.

Its a long winded scientific explanation, but it seems to work for chemicals passing across human/animal skin.

Lapis I think you missed my point of why you would take the chemicals preserving/anti bacterial properties into account - it would mean you could leave something longer and more safely so a formula for how long something would need etc would have to take this into account.

ps part of the reason we marinate is to tenderize the meat so that it cooks quicker or becomes softer, its not all about taste.

Steve

not sure I agree with your first point, and unless the marinade contains enzymes (from pineapple - bromelain, or papaya - papain) I don't think meat is tenderised by marinating, what process does that? Acids, like lemon/lime juice will denature surface proteins, but not affect the flesh underneath by reasoning of my first reply. Ionic substances (like acids) do not penetrate into the flesh. However, yoghurt does seem to have an affect, but I don't know why, maybe its to do with moisturising!

I think marinating is all about flavour, meat tenderising is about slow cooking.

Lapis, I know you know your stuff but something is missing with this data ? If I put a piece of meat in a mild acid (vinegar/lemon juice) it will break down, if you leave it long enough it will become a mush (which is how we break down food in our stomachs). Maybe the science is looking at it too closely and looking at reactions as a singular point rather than taking into account the things like meat are made up in 'strands' of 'fibre' which have spacing betweem them that can draw up any fluids and therefore allow the affect to get deeper into the meat than the lab test looks at ??

I know if I leave a piece of meat over night in a mild lemon/wine/olive oil and flavourings, that when cooked its more tender than untreated (as sometimes I will have mine 'messed about with' and my partner prefers hers plain).It also has the flavour right into the meat not just the outer edge.

Steve

Hi Steve,

the reason meat braks down in the stomach is that ut contains enzymes, called proteases. The acid is there to maintain an acid medium so that the enzymes work at (or near) their optimum pH conditions. Its the same reason why we put lemon juice on some fruit when we cut it, to stop the ezymes in the fruit (phenolase) acting on the fruit flesh. Here , the optimum pH is not near to lemon/lime juice (pH ~2.3) and so slows done the action of the enzyme.

I have often wondered how one works out if the marinade has penetrated the meat. Just popping it in the mouth will not tell us this. Most flavours will aDsorb to the surface of the meat.

I once did an experiment using yoghurt and two food dyes, one yellow and one orange (very similar solubilities in water). After leaving the chicken pieces for 24 hours (my ususal time) in the coloured yoghurt, one dye had penetrated twice as much as the other (I can't remember which) but neither had penetrated very far, maybe a few millimeters.

So if nothing really gets into the meat, nothing changes its texture then why have so many dishes appeared over the last hundreds/thousands of years that marinade meat ? Surely this must be down to something ? People must have put the meat in wine to store it and found it lasted longer or tasted better, became more tender so carried on doing it ?

Maybe its not the meat carrying the flavour and breaking down, which would explain why the tests you have quoted/carried out aren't showing it ? Could it be the fat content of the meat that is soaking up the flavours and also being broken down by some of the ingredients used ?

Steve

Hi Steve,

some marinades are usually water/juice/wine/vinegar based, using herbs as flavour sources. The meat, which has usually been around for a while, is beginning to dry out, and can therefore 'suck up' some of the flavour. Unfortunately, as soon as it is heated, it all comes out again. If we are lucky, some of the oil liking flavours will adsrorb onto fatty areas and perts of the protein molecules called beta plates, areas which are highly lipophilic.

Other marinades maybe be oil based. The flavour chemicals are adsorbed onto the surface of lipophilic proteins and fat regions, and over time, could penetrate the flesh a little. But I don't think it is all pervasive. It would be hard to tell the difference between adsorbtion onto the surface of the meat and absortion a little way into the meat. Most spice flavours will stick to fat, but fat is broken down by heat, not chemicals (except lipase ezymes!) else we would all be taking it!!

I always chuckle when I hear a 'celebrity chef' say the flavour has permeated into the meat. These are the same people who talk about sealing in flavour by frying, and caramelizing steaks. Like nearly everything in cookery, things are 'handed down', usually with blind faith.

I'm sure Mamta knows the story of the lamb joint with the end cut off, because mum did it that way.

My mum is a strict vegetarian Lapis, meat does not enter her kitchen. LOL!

Ususlly, one is supposed to make a few cuts/holes in the meat about to be marinated, for it to panetrate. I don't think it gets into the fibers, just into the spaces between groups of muscle and memberanes. Whatever it does or doesn't do sciaentifically, the tart ingredients make it tender and spices make it smell and taste it nice. I am not sure of the process, but marinating does make a difference.

I don't keep mine (meat in marinate) at room temperature for long, i am obsessive about bacteria etc. So can't do what Mr. Spice Namaste says unfortunately.

LOL!

MM, slashes meat to help penetration of marinade, does that not give us a clue?

I think we will have to agree to disagree on this one, but that's fine with me;?)

Bacteria is a big thing, of course. We are more knowledgeable now, and can take steps at home to provide safe food prep. To this end, I have about 8 or 9 chopping boards, and six or seven chef's knives to play with, so that I don't cross contaminate.

Some of the things I see celebrity chefs do on the TV make me wince. Do people still use wooden spoons and chopping boards? And the late Keith Floyd wipeing his finger in every dish to taste it. If he didn't add so much salt, would he have been so thirsty?

Bless him, hope he has plenty of wine where he is :-)!

hopefully not marinating in it!