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I'm not too sure what a Trans fatty acid is exactly!!! But hydrogenated vege oils
I know are rather revolting things... Margarine being the archetypeal hydrogenated
vege oil, since to begin with, the blended vege oils are the cheapest ones the
industry can buy, this is sometimes in some countries includes animals fats if they
are cheaper. After the oils have been hyrogenated to make them firm it is then bleached
since it looks something similar to used sump oil you find in your local
petrol garage after an oil change. After the bleaching it must be coloured yellow
and then varying amounts of animal fat added to make it smell/look more like butter.
I use to be a pastry cook and we had over 15 different types of margarines we
used for different types of pastries, but I know the biscuit industry in Australia
had over 145 different types of margarine a different one for each biscuit recipe...
It has long being recognised in Australia (though not officially) that margarine
contains a high number of carcinogens (sp??), check with one of the Uni's who do
food technology or their libraries for reports results of test or compositions.
I'd imagine the CSIRO in Oz has data about this, but can't think who in U.K. would
have anything..... But can you imagine what chemical process must be undertaken
to change a liquid at room temprature to a solid at room tempature by changing
the structure of molecules rather than thru other absortion type methods!!!!!
Scott "give me butter anytime", Esq.
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| I'm not too sure what a Trans fatty acid is exactly!!! But hydrogenated
vegie oils I know are rather revolting things.... Margarine being the
archetypeal hydrogenated vegie oil, since, to begin with, the blended
vegie oils are the cheapest ones the industry can buy, this is sometimes
in some countries includes animals fats if they are cheaper. After the
oils have been hyrogenated to make them firm it is then bleached. since
it naturally looks something similar to used sump oil you find in your
local petrol garage after an oil change. After the bleaching it must
be coloured yellow and then varying amounts of animal fat added to make
it smell/look more like butter. I used to be a pastry cook and we had
over 15 different types of margarines we used for different types of
pastries, but I know the biscuit industry in Australia had over 145
different types of margarine a different one for each biscuit
recipe....
It has long being recognised in Australia (though not officially) that
margarine contains a high number of carcinogens (sp??); check with one
of the Uni's who do food technology or their libraries for reports'
results of test or compositions.
I'd imagine the CSIRO in Oz has data about this, but can't think who
in the U.K. would have anything.... But can you imagine what chemical
process must be undertaken to change a liquid at room temperature to
a solid at room temperature by changing the structure of molecules
rather than thru other absortion type methods!!!!!
Scott "give me butter anytime", Esq.
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| Fatty acid biochemistry 101:
A fatty acid is an unbranched, unsubstituted alpha carboxylic acid with an
even number of carbon atoms. "Saturated" refers to the state of
hydrogenation. A saturated fatty acid has no double bonds and thus has as
much hydrogen as possible (i.e., it is saturated with hydrogen).
Unsaturated fatty acids contain one or more double bonds.
The general chemical formula for a saturated fatty acid is thus:
H-(CH2-CH2)n-CH2-COOH
the prototype for fatty acids is thus acetic acid (CH3-COOH), also known
as vinegar, which is case n=0. Case n=1 is butyric acid. Case n=6 is
myristic acid, n=7 is palmitic acid (one of the most common ones). For
most fatty acids, n is in the range 6-10.
Unsaturated fatty acids, as mentioned before, have one or more double
bonds. Fats formed from unsaturated fatty acids have lower melting points
than those formed from saturated fatty acids and therefore unsaturated
fatty acids tend to be liquid at room temperature (oils) whereas saturated
fatty acids tend to be solid at room temperature. This is why vegetable
oils have to be partially hydrogenated (i.e., some of the double bonds
turned back into single bonds) to form solid fats such as vegetable
shortening or margarine.
Carbon-carbon double bonds can't rotate the way that carbon-carbon single
bonds do. Therefore, there are two possible configruations about the
double bond in an unsaturated fat:
1) R-CH2 CH2-R' 2) R-CH2 H
\ / \ /
C=C C=C
/ \ / \
H H H CH2-R'
Configuration 1 is called the cis configuration (Latin for "on this side
of) because both hydrogens are on the same side of the double bond.
Configuration 2 is called the trans configuration (Latin for "beyond")
because one hydrogen is on the other side of the double bond. Fatty acids
with cis- double bonds are called cis-fatty acids. Those with double
bonds in the trans configruation are called trans-fatty acids.
It turns out that all the unsaturated fatty acids normally found in
naturally-occurring fats have all of their double bonds in the cis
configuration. This happens because the enzymes that dehydrogenate
saturated fatty acids to form unsaturated fatty acids are absolutely
specific for producing the cis form. But the chemical hydrogenation
processes used to partially hydrogenate vegetable oils do not have this
specificity, and thus you get trans-fatty acids in such products.
There are metabolic pathways in the cell for dealing with trans-fatty
acids (they occur in some bacterial cell walls), but they are a
side-branch of the normal, well-travelled pathways of fat breakdown.
I, too, would like to hear just what is allegedly so bad about trans-fatty
acids.
RE: .1, .2
I'd imagine the CSIRO in Oz has data about this, but can't think who
in the U.K. would have anything.... But can you imagine what chemical
process must be undertaken to change a liquid at room temperature to
a solid at room temperature by changing the structure of molecules
rather than thru other absortion type methods!!!!!
Nothing particularly drastic, certainly a lot less drastic than the
oxygenation and protein denaturation that occurs when you clarify butter.
As discussed above, the change from a liquid to a solid occurs because the
hydrogenation raises the melting point of the fat.
--PSW
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