This a physical measure of the degree of unsaturation in oil and fats.

IV is an expression of the degree of unsaturation of a fat. Usually the oxidative stability of an oil increases as the iodine value is lowered.

IV is a measure of the total number of unsaturated double bonds present in an oil. The determination of iodine value involves the addition of halogen in the presence of potassium iodide and titration with standard sodium thiosulphate using starch solution as the indicator. Of the various procedures available, the most widely used is the Wijs method. The higher the IV value, the lower the SMP since the presence of double bonds (less stable) will lower the melting point.