Two methods for determining the iodine value in vegetable oils are described. Calculation of iodine value from measurements of fatty acid. The quantity of substance used in the determination should be such that at least 70% of the iodine added, as provided in the recommended procedure, is not absorbed. It is expressed as the number of grams of iodine that will react with the. Iodine value test with cdr palmoiltester palm oil analysis system. For example, according to the literature 9 it is expected for soybean oil an iodine value between 118 and 9 g per 100 g, and the iodine value for the sample analyzed in this work by wijs method was. The mean value of the blank determination method 051b is automatically stored as auxiliary value h3. It is expressed as the number of grams of iodine that will react with the double bonds in 100 grams of fats or oils. Cdr palmoiltester iodine value test shows a good correlation with aocs official method cd 1d92. Determination of iodine value and acid value of red fruit. About 5 g of the dried homogenized fish sample were accurately weighed into a labelled thimble. To form a double bond, carbon requires more energy 615 kjmol than to form a single bond 350 kjmol.
The iodine value and slip melting point of palm oil, palm olein and palm stearin were determined in accordance to mpob test methods p3. It does not necessarily provide a measure of the carbons ability to absorb other species. The gammaray and xray photopeaks that are commonly used in the detection and quantification of these. Fast spectrophotometric determination of iodine value in biodiesel. Determination of fat contents, iodine values, trace and.
Determination of iodine content iodine titration free. The iodine value in chemistry is the mass of iodine in grams that is consumed by 100 grams of. The fat extraction was carried out by soxhlet extraction method. The international pharmacopoeia eighth edition pharmacopoea. One employs midinfrared midir spectroscopy and the other uses hydrogen nuclear magnetic resonance 1 h nmr. It is an indication of a fats it is an indication of a fats potential to be oxidized as it measures the reaction of iodine with the double bonds of unsaturated fatty acids 2. Pdf standard test method for determination of iodine. Measurement results this time shows favorable repeatability with 0. Two collaborative studies were conducted using the wijs method for determining the iodine value in a wide range of vegetable. If the iodine number is to be characteristic of the oil, the sample should be substantially free of moisture and foreign materials. Iodine value quality control 1 linkedin slideshare. This amount measured at 420 nm is indirectly related with concentration of double bond in the sample, expressed. The consensus values and their uncertainties were based on the acceptability of statistical agreement of results obtained from collaborating laboratories.
Calculation of iodine value from measurements of fatty. Determination of iodine value and acid value of red fruit oil. Figures 1 and 2 show the assignments of midir and 1 h nmr signals, respectively. Analytical methods the purpose of this chapter is to describe the analytical methods that are available for detecting, measuring, andor monitoring iodine and its radioisotopes, their metabolites, and other biomarkers of exposure and effect to iodine and its radioisotopes. Test method for measurement of iodine value of fats and oils stipulated in the below quoted standards is generally practiced by wijs method using monobasic.
Determination of iodine value of palm oil by differential. The higher the iodine value, the more unsaturated fatty acid bonds are present in a fat. Spectrophotometric determination of iodine analytical. Method a iodine monochloride method or wijs method. About 5 g of accurately weighed povidoneiodine is placed in a 400ml beaker, and 200 ml of distilled water is added. Determination of iodine value of fats and oil discover.
Determination of iodine species content in iodized salt and. Food and drug administration has approved potassium iodide as a thyroidblocking agent to reduce the risk of thyroid cancer in radiation emergencies. Food and drug administration, division of pesticide and industrial chemicals, washington, dc 20204. Dry method the simulated iodized salt sample was made by mixing potassium iodate 122. Iodized salt, which is readily available in the united states and many other countries. An iodine solution is yellowbrown in color and any chemical group in the substance that reacts with iodine will make. Estimation of iodine value of fats and oils reference. Iodine value test with cdr palmoiltester palm oil analysis. Iodine value is used as a parameter in process control as well as a quality parameter in traded palm oil products. The iodine value is the number which expresses in grams the quantity of halogen, calculated as iodine, which is absorbed by 100 g of the substance under the described conditions. It must be noted that a high iv value in oil consists of a greater number of double bonds than a low iv oil.
A new method of spectrophotometric determination of iodine in natural waters. This method provides an assay value for a sample of povidoneiodine. To determine the iodine value of fats and oils and thus estimate the unsaturation of the fat oil. Mar 31, 2020 iodine in the soil where they grew and in any fertilizer that was used. Determination of fat contents, iodine values, trace and toxic. Determination of iodine value of oil the iodine value is a measure of the degree of unsaturation in an oil.
The determination of the iodine value is based on either the transmittance intensity of midir signals or on the 1h nmr signal integration and multivariate calibration. Iodine value standard deviation coefficient of variation. The iodine recoveries for the second set of experiments in which desic cated hog thyroid powder was used are shown in table ii. Request pdf determination of the iodine value and the free fatty acid content of waste animal fat blends using ftnir this study determined iodine value iv and free fatty acids ffa content. Iodine value refers to the percentage of iodine absorbed by a substance such as a fat or oil 1. K 710 due to this reaction, solid iodine is soluble in solutions of iodide salts. Determination of iodine species content in iodized salt with various methods a. Fatty acids react with a halogen iodine resulting in the addition of the halogen at the cc double bond site.
Sources of errors in the determination of iodine value of. Simple methods via midir or 1h nmr spectroscopy for the. The recovery of iodine of this sample, analyzed statistically, was 100 f 4 per cent. Iodine number may be used as an approximation of surface area for some types of activated carbons see test method c819. This unsaturation is in the form of double bonds, which react with iodine compounds. It is used in the estimation of the degree of unsaturation in fatty acids. Analytical methods radiation detectors commonly utilize sodium iodide nai, hyperpure germanium, and organic liquid scintillation detectors to measure the gamma rays and xrays emitted from 125i and 1i. Accurately weigh quantity of substance being examined in a 300 ml iodine flask. However, most of the dissolved iodine is actually present as triiodide. Determination of the iodine value of oils and fats results. Determination of iodine value of oil lipids laboratory.
Each of the 11 materials were provided as blind duplicates i. Fresh palm oil had relatively lower iodine value of 45. This unsaturation is in the form of double bonds which react with iodine compounds. For example the theoretical iodine value of 100 g of linoliec acid would be 181 based on calculation as follows 100280. Iodine value iv was either predicted with an equation from aocs 1998 based on unsaturated fatty acid profile from the gc analysis or measured using near. An iodine solution is yellowbrown in color and any chemical group in the substance that reacts with iodine will make the color. The higher the iodine number is, the more unsaturated the fat. Iodine value iv is used as a parameter in process control as well as a quality parameter in traded palm oil products.
The double bonds present in unsaturated fatty acids react with the iodine. Standard test method for determination of iodine number of. It may be determined by any of the following methods. The intent is not to provide an exhaustive list of. Determination of iodine value iv in fats and oils with. The iodine values of different oils were also deter mined separately following the standard procedure of wijs, and calculated iodine value was obtained from the. Determination of iodine and saponification values of silver. Determination of the iodine value of oils and fats. This was transferred into a desiccator and allowed to cool. Iodine value or number is the number of grams of iodine consumed by 100g of fat. Petroleum iodine value of oil and fat kyoto electronics. 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. The result is expressed as g of iodine i2 per 100 g of sample. Apr, 2014 iodine value or number is the number of grams of iodine consumed by 100g of fat.
Principle double bonds react with iodine in alcoholic solution determining a variation in the reagents absorbance. A higher iodine value indicates a higher degree of unsaturation. Iodine value, in analytical chemistry, measure of the degree of unsaturation of an oil, fat, or wax. Palmbased standard reference materials for iodine value and. Iodine value was determined according to wijs method. 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. Iodine value is used to compare the number of cc contained in natural complex mixture. Processed foods, however, such as canned soups, almost never contain iodized salt. Iodine number wijs method continued under the test conditions.
Iodine value, also called iodine number, in analytical chemistry, measure of the degree of unsaturation of an oil, fat, or wax. To calculate the iodine number using the method described, below, all one need do is obtain the volume of na 2. Iodine value, also called iodine number or iodine index, is the mass of iodine in grams absorbed by 100 grams of oilfat. 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. As a result, iodine solutions are usually prepared by dissolving the solid in the presence of potassium iodide. Iodine number definition is a measure of the unsaturation of a substance as an oil or fat expressed as the number of grams of iodine or equivalent halogen absorbed by 100 grams of the substance. Iodine numbers are often used to determine the amount of unsaturation in fatty acids. However, conjugated double bonds are not present in.
The iodine value of a substance is the weight of halogens expressed as iodine absorbed by 100 parts by weight of the substance. Fat content determination using soxhlet extraction method. On the determination of iodine value by the wijs method. Hake iodine values of oil obtained from frozen fish obtained from the two sampling locations ranged from 50. 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. Bulletin of the chemical society of japan 1955, 28 7, 494497. The method is based on the quantitative determination of fatty acid methyl esters of vegetable oils by capillary gas chromatography. How do i calculate theoretical iodine value of an unsaturated. This hog thyroid powder was assayed five times by the u. Iodine value iv is a measure of the total number of double bonds present in fats and oils. Feb 06, 2012 iodine value iv is a measure of the total number of unsaturated double bonds present in fats and oils. Jojoba oil as an organic, shelf stable standard oilphase base for cosmetic industry pdf. 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.
Iodine value iv is a measure of the total number of unsaturated double bonds present in fats and oils. Sep 22, 2008 the iodine value and slip melting point of palm oil, palm olein and palm stearin were determined in accordance to mpob test methods p3. Determination of potassium iodide in table salt 154 iodine is a part of thyroid gland hormones thyroxine and triiodothyronine, that influence to normal growing and developing, regulate the speed of basic metabolism, create the energy and regulate the body temperature, influence on synthesis of proteins, changing. Estimation of iodine value of fats and oils theory. Indicate by structural formulas how iodine may add. Iodine value is proportional to the degree of unsaturation of the product and. Therefore, the thermal behavior of an oil could reflect its iodine value. The total iodine value also includes the iodide ions which are necessary for formation of the complex.
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. As a general rule, if the iodine number is in the range of 070, then youre looking at a fat. A green potentiometric method for the determination of the iodine. Determination of the iodine value and the free fatty acid. A new calculation method for the determination of iodine value iv from measurements of fatty acid methyl esters is proposed. Determination of iodine and saponification values of. It is normally expressed in terms of 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. Iodine gets incorporated into the fatty acid chain wherever the double bond exist. It is necessary to maintain close control of reaction conditions to assure reproducible results. Palmbased standard reference materials for iodine value. Iodine number definition of iodine number by merriamwebster.
Iodine reacts with iodide to produce the triiodide ion. This standard is issued under the fixed designation d 5768. Iv measures the number of double bonds in the molecular structure of an oil. Recovery of iodine of desiccated hog thyroid powder containing 0. Standard test method for determination of iodine value of. This unsaturation is in the form of double bonds, which. The amount of reagent absorbed is determined by back titrating the excess reagent and comparing it to a blank determination.
Alternative solvent system for iodine value determination. Iodine value of edible oils and fats according to wijs. Iodine valuenumber is defined as the g of iodine absorbed by 100g of the oil. Introduction the iodine value of animal and vegetable fats and oils measures the amount of cc double bonds present in the product. Hence, the measure of the iodine absorbed by an oil, gives the degree of unsaturation. Determination of iodine species content in iodized salt. To obtain the total iodine number of biodiesel samples astm.
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