Depends on concentration and pathlength
1 - 153mm (1/16"- 6")
A colorimetric test that uses the colour produced by the action of chemical reagents as a quantitative assessment of oxidative rancidity of fats and oils.
The test has been devised so that the colour intensity of the treated sample is reduced to 5 Lovibond® Red units or less, either by reducing the path length of the sample cell or by dilution.
Kreis values which indicate the level of rancidity are obtained using a simple equation based on Lovibond® Red units, the path length of cell in cm and the concentration of the oil.
The results are reported to be reproducible to 5 - 10%. Using this test, deterioration due to oxidation may be detected at a very early stage; fresh fats and oils that have not been kept under oxygen-free conditions give a positive reaction.