Determination of Energy Value of Food using Bomb Calorimeter

Energy Value of Food using Bomb Calorimeter:

Two methods can be used:

    1. Direct Calorimetry
    2. Indirect Calorimetry

Direct Calorimetry:

In direct calorimetry, the amount of heat produced by the body is measured. In this method, the individual is placed in a specially constructed chamber called a ‘respiration calorimeter’. The chamber is so well insulated that no heat can either enter into or escape through the walls. The heat given off by the individual performing an activity is picked up by the water flowing through coils in the chamber. The volume of water is known, rise in temperature is known and from these data, the calories expanded can be calculated.

These calorimeters are very expensive to construct and require careful attention in carrying out the experiment. Hence, they are used only in a few research centers.

Indirect Calorimetry:

This method is mostly used because it is simpler to use, the apparatus is small and anyone can operate it. This method is based on two assumptions:

    1. For all the oxidation processes oxygen is required.

    2. The intake of oxygen is equal to the carbon dioxide exhaled.