D1541 test method for total iodine value of drying oils and their derivatives. Determination of iodine and saponification values of. Acid value determination in vegetable oils 101 croat. Iodine value, in analytical chemistry, measure of the degree of unsaturation of an oil, fat, or wax. The determination is conducted by dissolving a weighed sample in a nonpolar solvent such as cyclohexane, then adding glacial acetic. Iodine value, also called iodine number or iodine index, is the mass of iodine in grams absorbed by 100 grams of oil fat. The determination is conducted by dissolving a weighed sample in a nonpolar. Determination of the iodine value of selected oils. No other units of measurement are included in this standard.
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. 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. Iodine value is important in determination of degree of unsaturated fat in oils and fatty acids. Calculations of the completeness of free acids extraction c from the oil test portion and the theoretical relative errors p for indirect titration of acidsa expected av mg koh1gofoil 0. To retard rancidity keep oils and fats in cool place and protect from light and air. 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. It is expressed as the number of grams of iodine that will react with the double bonds in 100 grams of fats or oils. Integration of the experiment into an upperlevel biochemistry laboratory is described. Determination of iodine content iodine titration free. The laboratory experiments on lipids earlier included the iodine absorption test, to compare semiquantitatively the degree of unsaturation in fatty acids present in common edible oils.
Fatty acids are long chain hydrocarbons with carboxyl groups cooh groups. Determination of saponification and iodine value of sunflower oil. This video looks at both the practical procedure and the calculation, for obtaining the iodine values of fats and oils. Iodine value of sunflower oil the determination of iodine value is of great importance in finding the proportion of adulteration in oils this gives an idea of its drying character. Introduced the iodine value was hubl which titrated fats in the presence of mercuric chloride with iodine, but with the actual reagent probably iodine chloride is formed in situ from mercuric chloride and iodine. Calculation of iodine value from measurements of fatty. Jan 14, 2020 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 higher the iodine value, the more unsaturated fatty acid bonds are present in a fat.
A modified determination of iodine value in fats, fatty acids, and fatty acid derivatives is reported. Introduction the acid value av is a common parameter in the specification of fats and oils. Estimation of iodine value of fats and oils theory. Determination of iodine value iv in fats and oils with. Iodine value iv is a measure of the total number of double bonds present in fats and oils. As a general rule, if the iodine number is in the range of 070, then youre looking at a fat. Determination of saponification and iodine value of.
Third edition experimental biochemistry, beedu sashidhar rao, vijay deshpande, i k international pvt. Taylor an introduction to practical biochemistry by david t plummer. In our experience, it is an important and easily available parameter in fat selection. The mean value of the blank determination method 051b is automatically stored as auxiliary value h3. Animal and vegetable fats and oils determination of iodine value. The described procedures, visual and potentiometric, have wide applicability and generate. If the iodine number is to be characteristic of the oil, the sample should be substantially free. It is used in the estimation of the degree of unsaturation in fatty acids. Triglycerides are made up of three fatty acids linked to glycerol by fatty acyl esters. The results obtained when using carbon tetrachloride were compared to those obtained when using a substitute solvent mixture of cyclohexane and glacial acetic acid. Albegarb, adam zajaca, kamil kostync, jadwiga lorenca, and jerzy hanuzad.
We have an intake of 50 students per year who, for practical exercises, are divided into two batches of 25. It must be noted that a high iv value in oil consists of a greater number of double bonds than a low iv oil. Albegarb, adam zajaca, kamil kostync, jadwiga lorenca, and jerzy hanuzad adepartment of bioorganic chemistry, institute of chemistry and food technology, faculty of engineering and. To calculate the iodine number using the method described, below, all one need do is obtain the volume of na 2. Describes 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. 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 result is expressed as g of iodine i2 per 100 g of sample. E691 practice for conducting an interlaboratory study to determine the precision of a test method. Determination of physicochemical constants of fats and. Determination of iodine value of fats and oil discover food. Annex a describes a method for the calculation of the iv from fatty acid compositional data. Annex b describes a method for the calculation of the iv from fatty acid compositional data. Standard methods for the analysis of oils, fats and derivatives.
The higher the iodine number is, the more unsaturated the fat. Determination of the iodine value of oils and fats results of. Standard test method for determination of iodine value of. We also have learned the right method to determine the iodine value in oil by titration with sodium thiosulphate for the second experiment. It is defined as the weight of koh in mg needed to neutralize the organic acids present in 1g of fat and it is a measure of the free fatty acids ffa in a sample of oil or fat indicates hydrolysis of triglycerides.
A new calculation method for the determination of iodine value iv from measurements of fatty acid methyl esters is proposed. 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. This unsaturation is in the form of double bonds which react with iodine compounds. Estimation of iodine value of fats and oils reference. In linoleic acid and cod liver oil the hanus method gives 2 to 4 per cent higher values than the other.
Quantitative determination of the iodine values of. Saponification value or saponification number, also referred to as sap in short, represents the number of milligrams of potassium hydroxide or sodium hydroxide required to saponify 1g of fat under the conditions specified. The larger the iodine value the greater the degree of. Iodine value, also called iodine number, in analytical chemistry, measure of the degree of unsaturation of an oil, fat, or wax.
The iodine value for native oils fats of defined plant origin is easily accessible from tables or from the fat supplier table 3. Introduction the iodine value of animal and vegetable fats and oils measures the amount of cc double bonds present in the product. The acid number is the quantity of base, expressed in milligrams of potassium hydroxide, that is required to. Jul 07, 2012 determination of iodine value iv along with factors like acid value, peroxide value, saponification value, solid fat index, refraction value, and trans fatty acid content is an important factor. Physicochemical constants such as the iodine value, the saponification value, the refractive index, the combustion heat, the specific gravity, the neutralization value, the iodinesaponification factor, and the hardness number are up to now the most important and the most often. Determination of iodine value of fats and oil discover. E177 practice for use of the terms precision and bias in astm test methods. Methods for the determination of iodine value huebls iodine.
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. Determination of iodine and saponification values of silver. Iodine number is a measure of the total number of double bonds present in fats and oils. Acid value determination in vegetable oils by indirect.
Standard test method for determination of the iodine value. The method is based on the quantitative determination of fatty acid methyl esters of vegetable oils by capillary gas chromatography. The total iodine value also includes the iodide ions which are necessary for formation of the complex. Determination of iodine value of oil lipids laboratory. D1959 test method for iodine value of drying oils and fatty acids. Iodine value is directly proportional to the degree of unsaturation of the fat oil ghee. 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. Standard methods for the analysis of oils, fats and. Iodine value of edible oils and fats according to wijs aoac. 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.
Pdf determination of iodine value in triisocetyl citrate. This method provides an assay value for a sample of povidoneiodine. Iodine value iv is a measure of the total number of unsaturated double bonds present in fats and oils. Iodine value and hydroxy value of chemical products and unsaponifiables 2 astm d 555895 standard test method for determination of the saponification value of fats and oils 3 iso 3657. Cautions in measurement 1 reagent and additives must be handled in a well ventilated room or in a draft. Determination of ffa and iodine value campuscrosswalk. Determination of acid value acidity, of iodine value, and of peroxide value.
Does hydrogenation affect the nutritional value of vegetable oils. An experiment has been developed that combines the ftir analysis of oils and fats with an iodometric titration. Determination of iodine value iv along with factors like acid value, peroxide value, saponification value, solid fat index, refraction value, and. Iodine value of edible oils and fats according to wijs. To determine the iodine value of fats and oils and thus estimate the unsaturation of the fats and oils. About 5 g of accurately weighed povidoneiodine is placed in a 400ml beaker, and 200 ml of distilled water is added. 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 calculation of the % ffa depends on the titrated type of sample.
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. Petroleum iodine value of oil and fat kyoto electronics. This standard is issued under the fixed designation d 5554. It is expressed as the iodine in grams that will react with the double bonds in 100 grams of fats or oils. The iodine value is a measure of the unsaturation of fats and oils and is expressed in terms of the number of. Determination of the iodine value of oils and fats results. The iodine value of animal and vegetable fats and oils measures the amount of cc double bonds present in the product. Pdf standard test method for determination of the iodine. On the determination of iodine value by the wijs method. 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 determination is carried out by dissolving a weighed sample in a nonpolar solvent such as cyclohexane. Determination of the iodine value of oils and fats. The double bonds present in unsaturated fatty acids react with the iodine. Moreover, we can also know the way to calculate the acid value of free fatty acid content. Quantitative determination of the iodine values of unsaturated plant oils using infrared and raman spectroscopy methods lucyna dyminska a, maciej calik, abduladhim moamer m. The method is suitable for edible fats and oils such as butter, olive, palm or sunflower oil. Moisture content of oils and fats is the loss in mass of the sample on heating. Determination of iodine value of oil the iodine value is a measure of the degree of unsaturation in an oil. Iv is a measure of the number of double bonds in the unsaturated fatty acids in one gram of oil. The iodine value is in direct proportion to the number of mono and polyunsaturated bonds within the constituent fatty acids.