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From:
Rakesh Bhardwaj <[log in to unmask]>
Reply To:
Rakesh Bhardwaj <[log in to unmask]>
Date:
Wed, 22 Jan 2014 01:37:31 -0800
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Dear All
To clear the confusion I would like to take some metabolic facts in consideration
Glucose after glycolysis enters TCA cycle as two molecules of acetyl CoA
Fatty acids after ß-oxidation also yields acetyl Co-A
Acetyl CoA yelds 12 ATPAnd conversion of acetic acid to acetyl CoA consumes 02 ATP.
So this net loss of 02 ATP in metabolism must be accounted (as in the case of proteins we subtract metabolic energy losses in Urea synthesis)
Net ATP synthesis from acetic acid is 10 ATP 
Calories per gram combustion of acetic acid is 3.48
 Acetic acid Glucose Carbohydrates/ sugars Palmitic acid
(fatty acid) Fats/Oils 
Molecular weight 60 180  256  
Net ATP yield per mole 10 36  129  
No. of moles ATP yield per gram 1/6 = 0.17 1/5 = 0.2  1/1.98 = 0.50  
Calorie value per gram ≈3.0 ≈3.75 ≈ 4.0 ≈9.5 ≈9.0 
When two monosaccharides are joined by glycosididic covalent linkage there is loss of one water molecule which results in higher calorie value compared to glucose
Oils/fats are triglyceride or tri acyl glycerols i.e. three fatty acids joined to one glycerol and in fat/oils energy yield is dependent on two important factors.
No. of carbons in fatty acid chain and no of double bonds. Longer chain and saturated fatty acids yield more energy than short chain and unsaturated fatty acids.
Acetic acid is best defined under organic acids category.

Dr. Rakesh Bhardwaj
Senior Scientist (Biochemistry)
Germplasm Evaluation Division
National Bureau of Plant Genetic Resources (NBPGR)
PUSA Campus, New Delhi - 110 012
India
Phone (+91)11-25848074(O),(+91)11-25842495(Fax)
(+91)9560487889 (M), (+91) 9015405449

From: Susanne Westenbrink <[log in to unmask]>
To: [log in to unmask] 
Sent: Tuesday, January 21, 2014 7:03 PM
Subject: energy factor for acetic acid?



Dear all, 

We have got a question concerning acetic acid. 
In the EuroFIR thesaurus this acid is assigned to the organic acids, but with the synonym: fatty acid C2:0. 
Our question is: how to deal with the energy calculation if a food, for instance vinegar, contains acetic acid. Is the amount of acetic acid multiplied by the energy factor for fat or for organic acids? Does any of you know more about the energy from acetic acid? And how did you deal with this in your food composition databases? 

Kind regards, 
Martine Jansen en Susanne Westenbrink 


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




Proclaimer RIVM http://www.rivm.nl/Proclaimer 

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