Ch.4 Energy Value of Food PDF

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Summary

Numerical Value of Food, breakdown of calories for carbohydrates, lipids, and proteins. ...

Description

Energy Value of Food Measurement of Food Energy 

A calorie (kcal) is a measure of heat and expresses a food’s energy value.

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o 1 kcal= the quantity of heat required to raise the temp of 1 kg of water 1 C

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British Thermal Unity (BTU)= the quantity of heat required to raise the o temperature of 1lb of water 1 F

Direct calorimetry 

Burning food in a bomb calorimeter permits the direct quantification of the foods energy content.

Energy Value of Macronutrients 

Carbohydrate= -Gross energy value 4.2 kcal/g -Net energy value 4 kcal/g (Atwater) -Varies with arrangement of carbohydrate molecule atoms. -Average coefficient of digestibility: 97%

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Lipid= - Gross energy value 9.4 kcal/g - Net energy value 9 kcal/g (Atwater) - Varies with structural composition of molecules fatty acids. - Average coefficient of digestibility: 95%

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Protein= - Gross energy value 5.65 kcal/g - Net energy value 4kcal/g (Atwater) - Affected by protein type and relative N2 content. - Average coefficient of digestibility: 92% -Net energy value for alcohol= 7kcal/g...