Nitrogen factor role in calorie calculation
I'm wondering what's the relation between nitrogen factor, protein factor and energy from total protein. i.e
Feta Cheese
Nitrogen Factor: 6.38
Protein Factor: 4.27
Total Protein: 21.3 g
and I know that:
Calories From Protein: 21.3 * 4.27 = 90.95 kcal
But I don't know how nitrogen factor affects calculation and where. I googled it but I didn't find what I was looking for(maybe use of bad keywords), I appreciate recommendation of any articles for my further reading.
Best Answer
Nitrogen factor appears to be a method of estimating protein content in a specific foodstuff based on the amount of nitrogen (since proteins are nitrogen rich). It is not exact, and there are different factors for different types of foods, to provide better estimates based on the ratios and types of proteins in those foods.
This 1931 USDA document gives an excellent background, even though it is somewhat of a bad scan, and challenging to read.
See also, for example, the FAO Conversion Table showing different factors for different foods.
As proteins are a calorific food, the nitrogen factor correlates with calories from protein because it helps you estimate the amount of protein in a food, and therefore the number of calories from protein based on the fact that protein has about 17 kJ or 4 kcal per gram.
Therefore, if you know you have g grams of a food, with a nitrogen factor of f, the estimated number of calories from protein c is:
c = g * f * 4
I was unable to find a definitive clear meaning of the phrase "protein factor" as it is a common phrase in biochemistry, evidently.
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How do you calculate nitrogen to calorie ratio?
The nonprotein kcalorie to nitrogen ratio (NPC:N) is calculated as follows:How do you calculate protein content in nitrogen?
On the basis of early determinations, the average nitrogen (N) content of proteins was found to be about 16 percent, which led to use of the calculation N x 6.25 (1/0.16 = 6.25) to convert nitrogen content into protein content.What KCAL N ratio is recommended for the healthy person?
Nonprotein Calorie to Nitrogen Ratio (NPC:N) A ratio of 150:1 to 200:1 is considered an adequate intake for stable patients.How many grams of nitrogen are in a gram of protein?
The nitrogen percentage of proteins in foods ranges from 15 to 24% [15]. For the calculation of the nitrogen content, a general nitrogen percentage of 16% is assumed. This results in a conversion factor of 6.25 g nitrogen per g protein.Calculation of Nitrogen Volume Factor |Basics of Nitrogen Operations |Yasir
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