It is expressed as the number of grams of iodine that will react with the double bonds in 100 grams of fats or oils the determination is conducted by dissolving a weighed sample in a nonpolar solvent such as cyclohexane, then adding glacial acetic acid. In the palm oil industry, the iv is an important parameter in quality control. In this method, a known weight of the fat or oil is dissolved in carbon tetrachloride. The iodine value is in direct proportion to the number of mono and polyunsaturated bonds within the constituent fatty acids. In our experience, it is an important and easily available parameter in fat selection. Animal and vegetable oils and fats known chemically as triglycerides have chains of carbon atoms that can bond with hydrogen. Standard methods for the analysis of oils, fats and. This document specifies a reference method for the determination of the iodine value commonly known in the industry as iv of animal and vegetable fats and oils, hereinafter referred to as fats. The iodine value for native oils fats of defined plant origin is easily accessible from tables or from the fat supplier table 3. This video looks at both the practical procedure and the calculation, for obtaining the iodine values of fats and oils. Iodine value is used to compare the number of cc contained in natural complex mixture. The larger the iodine value the greater the degree of unsaturation. Integration of the experiment into an upperlevel biochemistry laboratory is described. Theoil fat sample taken in carbontetrachlorideis treated with a known monochloride solution in exces s glacial of acetic iodine wijs solution.
On the determination of iodine value by the wijs method. Palmbased standard reference materials for iodine value. Hence the iodine number of the oil is 260x45 results and discussion the iodine number is an important characteristic of oils as it. It is used in the estimation of the degree of unsaturation in fatty acids. Determination of iodine value iv in fats and oils iodine value iv is a measure of the total number of double bonds present in fats and oils. A higher iodine value indicates a higher degree of unsaturation. An annex describes a method for the calculation of the iv from fatty acid compositional data. Estimation of iodine value of fats and oils reference. When the carbon atoms in these chains are bonded to the maximum possible number of hydrogen atoms, the triglyceride is said. Iodine value is a useful parameter in studying oxidative rancidity of oils since higher the unsaturation the greater the possibility of the oils to go rancid. The calculation of the % ffa depends on the titrated type of sample. The iodine value of an oil fat is the number of grams of iodine absorbed by 100g of the oil fat, when determined by using wijssolution.
Measurement results this time shows favorable repeatability with 0. Fat and oil saponification value of fat and oil acid. If the iodine number is to be characteristic of the oil, the sample should be substantially free of moisture and foreign materials. For the determination of the iodine number of oleic and ricin oleic acids both the hanus and the rosenmund methods give the same value which is very near the theoretical. Estimation of iodine value of fats and oils youtube. Can we calculate unsaturated fatty acids % by iodine value. Cdr palmoiltester iodine value test shows a good correlation with aocs official method cd 1d92. Because the melting point and oxidative stability are related to the degree of unsaturation, iv provides an estimation of these quality factors. The iodine value, or iodine adsorption value, is used in analytical chemistry to measure the amount of unsaturation of oils and fats. The iodine number is by definition the amount of iodine in gram.
It is expressed as the number of grams of iodine that will react with the double bonds in 100 grams of fats or oils. Iodine value it is defined as thenumber of grams of iodine which combines with 100 grams of the fat or oil. The method is based on the quantitative determination of fatty acid methyl esters of vegetable oils by capillary gas chromatography. Pdf determination of iodine value in triisocetyl citrate. Standard test method for determination of iodine value of. Palmbased standard reference materials for iodine value and. Oct 15, 2007 the iodine value is a measure of how much iodine will add to the double bonds of the oil. The double bonds present in unsaturated fatty acids react with the iodine. Iodine value iv is a measure of the unsaturation of oils and fats. Determination of iodine value of palm oil by fourier. Applicable to all normal fats and oils with iodine values in the range of 18165 that do not contain conjugated double bonds. The main representative of milk fats is the fat of cows milk milk fat, butter fat, butter oil.
Determination of the iodine value and the free fatty acid. The results obtained when using carbon tetrachloride were compared to those obtained when using a substitute solvent mixture of cyclohexane and glacial acetic acid. A b s t r a c t the iodine value iv also called iodine number or iodine absorption value is an important analytical characteristic of unsaturation of fats and oils. Deterioration in the vegetable oils is reflected by the decrease in iodine value. The mean value of the blank determination method 051b is automatically stored as auxiliary value h3. Iodine value of edible oils and fats according to wijs aoac method 1 dissolve the sample in ccl 4, add 25 ml wijs solution and keep in the dark for approx. Determination of iodine value of fats and oil discover. Iodine value, also called iodine number or iodine index, is the mass of iodine in grams absorbed by 100 grams of oil fat. Saponification of oil pdf saponification value is expressed by potassium hydroxide in mg required to.
Iodine value is used as a parameter in process control as well as a quality parameter in traded palm oil products. Determination of the iodine value of selected oils. Iodine value iv the iodine value is a measure of the relative degree of unsaturation in oil components, as determined by the uptake of halogen. Thanks to its simplicity, the innovative cdr method for the determination of iodine value iv in palm oil is ideal to be used during every process stage to monitor the quality of oil in real time and during the acceptance of crude oil, as well as during trading of finished products. Iodine number determination using ftir atr spectroscopy. Introduction the iodine value of animal and vegetable fats and oils measures the amount of cc double bonds present in the product. Introduction the acid value av is one of the most common parameters to measure the free fatty acids present in a sample of fat or oil. In linoleic acid and cod liver oil the hanus method gives 2 to 4 per cent higher values than the other. Iodine value iv is a measure of the total number of double bonds present in fats and oils.
Determination of the iodine value and the free fatty acid content of waste animal fat blends using ftnir article in vibrational spectroscopy 72. Kaufmann 4 related methods of analysis 5 references table of iodine values edit fat iodine number1 tung oil 163 173 cod liver oil 145 180 grape seed oil 124 1442. Triglycerides are made up of three fatty acids linked to glycerol by fatty acy. The results of a statistical evaluation of the iodine values obtained in the 1st collaborative study in which 11 laboratories from 9 countries participated are summarised in table 2. D1959 test method for iodine value of drying oils and fatty acids. Evaluation of saponification value, iodine value and. To determine the iodine value of fats and oils and thus estimate the unsaturation of the fats and oils. 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. Determination of the iodine value of oils and fats. It is defined as the number of milligram of potassium hydroxide koh needed to neutralise the free fatty acid ffa present in one gram of fats or oil through titration with standard koh in the presence of phenolphthalein as the indicator. Iodine value of edible oils and fats according to wijs. The method is suitable for edible fats and oils such as butter, olive, palm or sunflower oil. Iodine value is a measure of the number of double bonds in the unsaturated fatty acids in one gram of oil. Apr, 2014 a higher iodine value indicates a higher degree of unsaturation.
Oils and fats are important parts of human diet and more than 90 per cent of the world production from vegetable, animal and marine sources is used as food or as an ingredient in food products. The iodine value in chemistry is the mass of iodine in grams that is consumed by 100 grams of. Iodine value test with cdr palmoiltester palm oil analysis. This left fewer available for the iodine to add to, hence a lower value. From this alignment chart we can read the saponi fication value, refractive index, neutralization value, specific gravity, combustion heat, iodinesaponification. The iodine value is a measure of the unsaturation of fats and oils and is expressed in terms of the number of centigrams of iodine absorbed per gram of sample. On the other hand, linseed oil is highly unsaturated, which makes it a drying oil. The old oil oxidized in part, oxygen reacting with some of the double bonds. What is the standard procedure to determine the iodine value. Since 450 mg of the oil takes up 26x mg of iodine 1 mg of the oil will take up 26x450 mg of iodine and 100 mg of the oil will take up 260x45 mg of iodine. Aocs official method cd 1d92 aocs american oil chemists.
Iodine value iv is used as a parameter in process control as well as a quality parameter in traded palm oil products. The acid number is the quantity of base, expressed in milligrams of potassium hydroxide, that is required to. Determination of iodine value of oil the iodine value is a measure of the degree of unsaturation in an oil. E691 practice for conducting an interlaboratory study to determine the precision of a test method. This unsaturation is in the form of double bonds, which. Estimation of iodine value of fats and oils amrita university. The higher the iodine number is, the more unsaturated the fat. The iodine value is expressed in grams of iodine for the amount of halogens linked with 100g test sample, and is used as degree of unsaturated bond of fats and oils. Dec, 2015 this video looks at both the practical procedure and the calculation, for obtaining the iodine values of fats and oils.
Other edible oils, commonly consumed in a particular area, may be given to the students for this exercise. Annex a describes a method for the calculation of the iv from fatty acid compositional data. Saponification of this oil yields a soap that is an important constituent of toilet soaps. The iodine number measures the degree of unsaturation of fatty acids this reaction does not occur with saturated fatty acids, at all. This is then treated with a known excess of standard. What is the standard procedure to determine the iodine. Petroleum iodine value of oil and fat redox titration by automatic potentiometric titrator standard jis k 0070 astm d 1959 iso 3961 1. The iodine value is a measure of the unsaturation of fats and oils and is expressed in terms of the number of centigrams of iodine absorbed per gram of sample % iodine absorbed. Determination of acid value acidity, of iodine value, and of peroxide value. Determination of the iodine value of oils and fats results of. Therefore, iv analysis is a routine activity in the palm oil industry 29.
The iodine value of fat is another method of measuring the hardness or softness of fat. The higher the iodine number, the more cc bonds are present in the fat. This data has been supplied by the australian renderers association and. Also higher iodine values are evidence that the oils could be used in the manufacture of cosmetics, oil paints and vanish, as well as nutritional purposes 11. Iodine value, also called iodine number, in analytical chemistry, measure of the degree of unsaturation of an oil, fat, or wax. Iodine numbers are often used to determine the amount of unsaturation in fatty acids. This unsaturation is in the form of double bonds which react with iodine compounds. Thirtythree laboratories collaborated in the interlaboratory proficiency tests for characterization of iodine value, while thirtytwo laboratories for characterization of slip melting point. A new calculation method for the determination of iodine value iv from measurements of fatty acid methyl esters is proposed. Annex b describes a method for the calculation of the iv from fatty acid compositional data.
Sep 22, 2008 this work described study protocols on the production of palmbased standard reference materials for iodine value and slip melting point. This unsaturation is in the form of double bonds, which react with iodine compounds. 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 100 grams of a chemical substance. D1541 test method for total iodine value of drying oils and their derivatives. Determination of the iodine value of oils and fats results. While it is most appropriate for a sophomore or junior laboratory for majors, it also makes a suitable group project or demonstration for nonscience majors.
An experiment has been developed that combines the ftir analysis of oils and fats with an iodometric titration. Impact of frying on iodine value of vegetable oils before. All other milks are of almost no importance as far as their fats are concerned. Animal fats can be categorized as milk fats, rendered fats, and fish oils marine oils. Collaborative test of determination of iodine value in. To determine the iodine value of fats and oils and thus estimate the unsaturation of the fat oil. Scope applicable to all normal fats and oils with iodine values in the range of 18165 that do not. Determination of iodine value of palm oil by differential scanning calorimetry article pdf available in journal of the american oil chemists society 748. Fatty acids are long chain hydrocarbons with carboxyl groups cooh groups. 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 100. Iv depends on the value of the unsaturated fatty acids in the oil.
Determination of iodine value iv in fats and oils using. Aocs official method cd 1d92 american oil chemists society. Estimation of iodine value of fats and oils procedure. Abstract test method for measurement of iodine value of fats and oils stipulated in the below. Iv is a measure of the number of double bonds in the unsaturated fatty acids in one gram of oil. Iodine value means the g value of halogen which adhere to g of methods such as hanus method and wijs method for iodine value. We have found that, after one practice session, the students can determine the iodine numbers of oils with a fair degree of accuracy. Iodine number of oils and fatty acids txdot designation. Abstract saponification value is expressed by potassi um hydroxide in mg required to saponify one 1 gram of fat. The iodine value is a measure of the unsaturation of fats and oils and is expressed in terms of the number of centigrams of iodine absorbed per gram of test sample % iodine absorbed. It is expressed as the number of grams of iodine absorbed by 100 grams of oil or fat under the test conditions 1.
Impact of frying on iodine value of vegetable oils before and. Two collaborative studies were conducted using the wijs method for determining the iodine value in a wide range of vegetable and animal oils and fats. The iodine value of an oilfat is the number of grams of iodine absorbed by 100g of oilfat. Double bonds react with iodine in alcoholic solution determining a variation in the reagents absorbance. As a general rule, if the iodine number is in the range of 070, then. The result is expressed as g of iodine i2 per 100 g of sample. Straightforward determination of iodine value in fats and. The amount of unsaturation in fat samples is therefore often determined industrially and is termed the iodine number of the fat. Iodine value test with cdr palmoiltester palm oil analysis system. Estimation of iodine value of fats and oils theory.
Ftnir allows the monitoring physical and chemical properties of the lipids including fatty acid profile, free fatty acids, trans fatty acids, iodine value or sfc content. Iodine value is used to measure unsaturation or the average number of double bonds in fats and oils. This international standard specifies a reference method for the determination of the iodine value commonly known in the industry as iv of animal and vegetable fats and oils, hereinafter referred to as fats. Standard test method for determination of the iodine value of. Astmd5554 standard test method for determination of the. Petroleum iodine value of oil and fat kyoto electronics.
The higher the iodine value, the more unsaturated fatty acid bonds are present in a fat. E177 practice for use of the terms precision and bias in astm test methods. Triglycerides are made up of three fatty acids linked to glycerol by fatty acyl esters. High iodine value indicates high unsaturation of fats and oils and lowiv oils are more saturated with fewer doublebonds 11. Determination of physicochemical constants of fats and oils from the. Determination of iodine value of oil lipids laboratory. Jul 07, 2012 estimation of iodine value of fats and oils amrita university. This work described study protocols on the production of palmbased standard reference materials for iodine value and slip melting point. It is defined as the number of grams of iodine that could be added to 100 g of oil, which is measured with the aocs method cd 125.
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