Iodine value means the “g” value of halogen which adhere to g of methods such as Hanus method and Wijs method for Iodine value. The processors of oil and fat are in need of a quick determination method of iodine value of oils and fats especially in case of checking the degree of. This test method covers the determination of the iodine value of fats and iodine value of fats and oils that do not contain conjugated 3 Wijs Solution ( Iodine Monochloride Solution) may be purchased commercially. 1.

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Reproduced material should be attributed as follows: So handle the reagent with gloves.

Information related to the author. So it is important to know the extend to which a fatty acid is unsaturated. Views Read Edit View history. Analytical chemistry Dimensionless numbers of chemistry Iodine. Journal of Oleo Science.

The Wijs method as the standard for iodine absorption – Analyst (RSC Publishing)

Unsaturated fatty acids can be converted into saturated by the process of hydrogenation. This would lead to undesirable side reactions, and thus falsifying a result consumption of bromine.

Already have an account? Fatty acids are long chain hydrocarbons with carboxyl groups COOH groups. Addition of iodine chloride and back-titration with sodium thiosulphate by DIN Mercuric acetate, however, cannot be empolyed now because the reaction solution is hard to meet the regulation of water pollution and its disposal has become difficult. Saturated fatty acids contain only single bond between the carbon atoms and are tend to be solids at room temperature.


Starch is used as the indicator for this reaction so that the liberated iodine will react with starch to give purple coloured product and thus the endpoint can be observed. This quick Wijs’ method gives almost equivalent value of Hoffman’s although it tends to give less value than that of the Wijs’ method. This may take some time to load.

Depending upon the degree of unsaturation, the fatty acids can combine with oxygen or halogens to form saturated fatty acids. They are likely to exists as liquids at room temperature. Bromination of the double bonds in the dark, reducing the excess bromine with iodidebacktitration of iodine with thiosulfate. For reproduction of material from PPS: March 17, Released: Previous article Next article.

If you are the author of this article you do not need to formally request permission to reproduce figures, diagrams etc. Journal of Oil Chemists’ Society, Japan.

Iodine value

To determine the iodine value of fats and oils and thus estimate the unsaturation of the fats and oils. By using this site, you agree to the Terms of Use and Privacy Policy. Register Already have an account? Hoffman and Green modified the Wijs’ method by employing mercuric acetate as catalyst and made it possible to determine the iodine value of a sample in ten minutes or so. For reproduction of material from all other RSC journals and books: Jump to site search.

Authors have investigated other methods of quick determination of iodine value especially for the oils in the hydrogenation process and have found after all the Wijs’ method could be appropriate by only shortening the reaction time to three minutes for the oils of the iodine value less than about Retrieved 1 Januaryfrom vlab. Rapeseed and Canola Oil: This reaction must be carried out in the dark, since the formation of bromine radicals is suppressed by light. If you are not the author of this article and you wish to reproduce material from it in a third party non-RSC publication you must formally request permission using Copyright Clearance Center.


This unsaturation is in the form of double bondswhich react with iodine compounds. This particular analysis is an example of iodometry. The iodine value or iodine adsorption value or iodine number or iodine index in chemistry is the mass of iodine in grams that is consumed by grams of a chemical substance. Back to tab navigation Fetching data from CrossRef. A higher iodine value indicates a higher degree of unsaturation.

Iodine numbers are often used to determine the amount of unsaturation in fatty acids. December 20, received: Trans fatty acids are associated with health problems and cardiovascular diseases.

Journal of Japan Oil Chemists’ Society. Wheat germ oil [5]. XX is the XXth reference in the list of references.

The double bonds present metyod the naturally occurring unsaturated fats are in the Cis form. Go to our Instructions for using Copyright Clearance Center page for details. The first page of this article is displayed as the abstract.