The list of components presented in this food composition data is identical for all foods. Certain components are described below.
Fat and fatty acids
In most foods, fat is mainly composed of triacylglycerol molecules, made from a glycerol core, esterified by 3 fatty acids.
Depending on the food group and the type of fat in the food, fatty acids represent 56 to 95% of total fat, the remaining fraction containing glycerol, molecules that cannot be saponified (sterol compounds, fat-soluble vitamins), and sometimes phosphate groups etc. This is why the fatty acid classes do not add up to the total fat.
The Regulation EU No 1169/2011 on the provision of food information to consumers defines 'carbohydrate' as any carbohydrate which is metabolized in man, and includes polyols.
Protein and crude protein
In this food composition table, values for "Protein" are obtained by multiplying total nitrogen by a specific conversion factor (Jones factors) depending on the food group (e.g. 6.38 for dairy products, 5.95 for rice). This approach, despite its imperfections, takes into account variability of the nitrogen/protein ratio among food groups.
For nutritional labelling in Europe, "Protein, crudes, N x 6,25" values are calculated by multiplying total nitrogen by 6.25 for all foods (Regulation EU No 1169/2011 on the provision of food information to consumers).
There are several methods to calculate energy content of foods.
The values in the present table have been calculated for each foods using the following factors:
- 37 kJ/g (9.0 kcal/g) for fat
- 29 kJ/g (7.0 kcal/g) for alcohol
- 17 kJ/g (4.0 kcal/g) for protein
- 17 kJ/g (4.0 kcal/g) for carbohydrates (except for polyols)
- 13 kJ/g (3.0 kcal/g) for organic acids
- 10 kJ/g (2,4 kcal/g) for polyols
except for erythritol 0 kJ/g (0 kcal/g)
o 8 kJ/g (2 kcal/g) for dietary fibers.
"Energy, N x Jones' factor, with fibres" has been calculated using values for "Protein", obtained by multiplying total nitrogen by a specific conversion factor (Jones factors) depending on the food group (e.g. 6.38 for dairy products).
However, "Energy, Regulation EU No 1169/2011" has been calculated according to the Regulation UE No 1169/2011, which uses "Protein, crude, N x 6,25", obtained by multiplying total nitrogen by 6.25 for all foods.
Several components show a vitamin A activity: retinol but also some carotenoids.
Different formulas have been proposed to calculate vitamin A activity:
- Vitamin A activity (expressed in µg retinol equivalents, RE) = retinol (in µg) + 1/6 beta-carotene (in µg) (joint FAO/OMS expert consultation, 1967)
- Vitamin A activity (expressed in µg retinol equivalents, RE) = retinol (in µg) + 1/6 beta-carotene (in µg)+ 1/12 other carotenoid Vitamin A precursors. This can also be expressed as µg retinol + 1/6 µg beta-carotene equivalents (US National Academy of Science, 1974).
- Vitamin A activity (expressed in µg retinol activity equivalents, RAE) = all-trans-retinol (in µg) + all-trans-beta-carotene/12 (in µg) + other provitamin A carotenoids/24 (in µg). The RAE conversion factors are based on recent studies that show that the conversion of provitamin A carotenoids to retinol is only half as great as previously thought (Composition of Foods, Raw, Processed, Prepared, USDA National Nutrient Database for Standard Reference, Release 20, September 2007).
Due to the ongoing discussions on retinol equivalence of carotenoids and because of their properties other than Vitamin A activity, the food composition data provides separate values for retinol and carotene.