Dear all,

Many thanks to Esther, Erling, Anders, Rakesh and Paul for replying to our 
question. This has helped to get things clearer. 
We do use the European legislation to calculate energy in foods, which 
means that we apply specific factors for e.g. organic acids and polyols. 
My main question was about where to put acetic acid, as this compount is 
both indicated as organic acid and fatty acid F2;0. So far we only have 
zero values in our database, so any change will not have an inpact on 
energy values. When adding an acetic acid value for vinegar and related 
foods we need to apply the correct approach. 

From the discussion we have concluded that acetic acid (F2:0) must be 
treated as an organic acid and not as fatty acid. Acetic acid it is a 
building block of natural fatty acids but, unlike them, does not occur in 
natural triglycerides (Chebi). And with the usual analytical methods, they 
do not turn up in the value for fat/fatty acids. You need special 
analytical methods to determine the amount of organic acids, as indicated 
by Anders. In the NEVO database we will attribute ~3 kcal /g organic 
acids, and not include acetic acid in the sum of saturated fatty acids.

To continue the discussion: 
Following this, the next question pops up for other short chain fatty 
acids/organic acids. On internet 
(http://www.cyberlipid.org/fa/acid0001.htm#1) I found information that 
stated that short chain fatty acids (below 4- 6 Carbons) should/could be 
regarded as organic acids. Up to 6 (or 4) carbon atoms, organic acids are 
considered "short-chain organic acids", they have substantial solubility 
in water. Furthermore, they do not behave physiologically like other fatty 
acids since they are more rapidly digested and absorbed in the intestinal 
tract and have unique properties in regulating sodium and water absorption 
through the mucosal epithelium. Biochemically, they are more closely 
related to carbohydrates than to fats. However I am not sure how reliable 
this website is. 

Propanoic acid is listed as organic acid in the EuroFIR component 
thesaurus and as fatty acid by Chebi (I could not find it in the INFOODS 
tagnames). Is this measured through fatty acid analyses methods? Is it a 
relevant component in food?  If available in a food comp database, should 
3 or 9 kcal be calculated for energy?
What is your opinion on this?

Butyric acid (F4:0) is classified as fatty acid in both the EuroFIR 
component thesaurus and the Chebi database. I know this is measured in 
fatty acid analyses, we have several values. My conclusion would be that 
F4:0 must be treated as a fatty acid, yielding ~ 9 kcal/g. (This what we 
have been doing all the time).
Do you agree on this conclusion for  butyric acid?


EuroFIR component thesaurus:
Acetic acid classified as organic acid, with synonym F2;0
Propanoic acid: classified as organic acid with synonym F3;0
Butyric acid classified as saturated fatty acids (F4:0)

Chebi database:
Acetic acid F2:0 Chebi 15366: building block of natural fatty acids which, 
unlike them, does not occur in natural triglycerides. 
Propanoic acid F3:0 chebi 30768: The smallest H(CH2)nCOOH acid that 
exhibits the properties of the other fatty cids.
Butyric acid F4:0 Chebi 30772: four carbon straight-chain saturated fatty 
acid

Looking forward to your reaction,
with best wishes,
Susanne and Martine


Susanne Westenbrink
Rijksinstituut voor Volksgezondheid en Milieu (RIVM) / National Institute 
for Public Health and the Environment
Centrum voor Voeding, Preventie en Zorg / Centre for Nutrition, Prevention 
and Health Services
PO Box 1
3720 BA Bilthoven
The Netherlands
tel:  +31 (0) 30 274 2448
fax: +31 (0) 30 274 4466
e-mail: [log in to unmask]
for more information on  the Dutch food composition database see 
http://www.rivm.nl/nevo
http://nevo-online.rivm.nl




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