GIFSQ Tools · Module 1 — Food Composition & Proximate Analysis · Tool 11 of 500
Carbohydrate is not measured directly — it is what is left after moisture, ash, protein and fat are taken from 100. Enter the proximate values to get total and available carbohydrate.
Try sample values — fills the form with the worked example below.
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Total carbohydrate (%)
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Available carbohydrate (%)
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Remainder checked (%)
Equation: Total carbohydrate % = 100 − (moisture % + ash % + protein % + fat %)
Available carbohydrate % = Total carbohydrate % − dietary fibre %.
Method: Carbohydrate by difference, AOAC / FAO proximate analysis practice (FAO Food and Nutrition Paper 77, carbohydrate by difference; AOAC 986.25 for the proximate set it draws on).
Assumptions: the four measured values are on the same basis (all as received, or all dry basis); every other component has been measured, so the remainder is carbohydrate.
Limitations: every error in moisture, ash, protein or fat lands in the carbohydrate number; the result counts fibre as carbohydrate, so use available carbohydrate when fibre is known; it does not tell which sugars or starches are present.
Rounding: results to 2 decimal places; intermediate values are not rounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Available carbohydrate % = Total carbohydrate % − dietary fibre %.
Method: Carbohydrate by difference, AOAC / FAO proximate analysis practice (FAO Food and Nutrition Paper 77, carbohydrate by difference; AOAC 986.25 for the proximate set it draws on).
Assumptions: the four measured values are on the same basis (all as received, or all dry basis); every other component has been measured, so the remainder is carbohydrate.
Limitations: every error in moisture, ash, protein or fat lands in the carbohydrate number; the result counts fibre as carbohydrate, so use available carbohydrate when fibre is known; it does not tell which sugars or starches are present.
Rounding: results to 2 decimal places; intermediate values are not rounded.
This is a calculation aid, not a laboratory report — confirm against your accredited method before citing a value.
Worked example: Moisture 12.00 %, ash 1.50 %, protein 10.00 %, fat 2.00 %. Total carbohydrate = 100 − (12.00 + 1.50 + 10.00 + 2.00) = 100 − 25.50 = 74.50 %. With dietary fibre 5.00 %, available carbohydrate = 74.50 − 5.00 = 69.50 %.
Enter values above to see results.
Typical total carbohydrate: wheat flour 72–76 %, white bread 49–52 %, cooked rice 28–30 %. If the four values add up to more than 100 %, check the inputs — the remainder cannot be negative. Tool 11 of 500 — GIFSQ
