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Marination
Not just a matter of good taste
Marination is a good idea for
many reasons - but only under the right conditions. Many advocate it
as vital to real taste and others disagree or cannot really be
bothered, but few really understand the science behind their
reasoning. It acts as a form of pre-digestion: protein-digesting
enzymes from plants, such as papaya, fig and pineapple break down
muscle and connective tissue in meat and acids, such as vitamin C
(lemon juice/orange juice) and vinegars emulate the natural action of
lactic acid naturally produced by a living body to break down the
proteins for use.
Marination can also be
attractive by introducing colour and flavour to the areas in which it
comes into contact and in those layers near the surface of the tissue.
It is also a useful combatant of harmful bacteria and
moulds, its usually acid nature inhibiting their growth, and when a
antibacterial spice, such as turmeric, is used in the marinade, this
is reinforced.
With a piece of chicken accumulating anything up to
10,000 bacteria per square centimetre by the time it reaches the
supermarkets - even under strictly controlled conditions - this is
very comforting.
Studies carried out at the Lawrence Livermore National
Laboratory in California, indicate that chicken marinated before
grilling contains fewer carcinogens, the substances that may produce
cancer in living tissues. Dr Mark Knize and
his team marinated chicken breast in olive oil, brown sugar, cider
vinegar, lemon juice, garlic, salt and mustard. After cooking it for
20 minutes, they found that it had one-tenth the usual level of
heterocyclic amines or less.
Quite a powerful weapon in the cook's armoury, one
might say. However, as with all weapons, it is a two edged sword. Marination
is a chemical reaction and needs the physical contact of marinade and
meat tissue. This takes place at the surface. The centre of the meat
is still subject to the natural forms of decomposition. Lactic acid
builds up and breaks down the protein, naturally tenderising the meat.
The fat tissue within the meat is no longer supplied
with white blood cells and antioxidants, so becomes infected and
quickly rancid and those meats which are high in unsaturated fats -
fish, poultry, pork, lamb and veal are those which spoil the
quickest. This is why marination should be under refrigeration, and
for a matter of hours rather than days, to allow flavours to permeate
- over-marination just leads to mushy tissue surrounding microbe rich centres.
Scientists have found that the optimum temperature for
tenderisers to work well is between 60ºC - 79ºC and are
deactivated at boiling point - (100ºC). So the main tenderising
action probably acts upon the muscle tissue in the early stages of
the actual cooking.
Whatever the pitfalls of modern marination,
it is a vast improvement on the methods used up until the end of the
last century. Beef joints were hung in storage until the outsides
were literally rotten.
The French called this process mortification - but, at
the stage of putrefaction they preferred, whose death they were
referring to is now lost in the mists of time. |