ABSTRACT
The bomb calorimeter can be used to measure enthalpy changes when various molecules are oxidised to carbon dioxide and water. Table 2 . 1 shows that different food ma terials have different enthalpy values of oxidation when expressed in units of kJ mol-1 . Thus glucose has a value of 2817kJ mol-t, approximately twice that of lactate . Palmitic acid, a typical fat, has a value of 1 0 040 kJ mol-1 , whereas a s imple amino acid such as glycine has a value of 979 kJ mol-I. when expressed in units of tern emerges. Carbohydrate material gives a con-
heat given out by the animal over a period of time. Some, such as the Atwater-Rosa calorimeter, comprise a large insulated chamber with heat production being measured by the temperature difference between inflow and outflow of a cooling stream of water piped through the chamber containing the subject (usually human). are more truly adiabatic, where the heat produced raises temperature of the surrounding walls . Thermocouples monitor the temperature rise of the surrounding material and it is a rolatively simple calculation to relate this to the heat changes in the chamber. A portable suit calorimeter has even been developed where the subject (again usually human) wears a water-cooled undergarment covered by insulating outer layer.
