Principle Peroxide value is a measure of the peroxides contained in the oil. Zaidin Hoijin Sugiyama Sangyo Kagaku Kenkyusho Original Assignee Zaidin Hoijin Sugiyama Sangyo Kagaku Kenkyusho Priority date The priority date is an assumption and is not a legal conclusion. After the induction period, during which the peroxide value increases slowly, a steep increase indicates that the oil has gone bad. Therefore, they can be of no or hardly any use as the test paper for the purpose of the present invention. Ralf Bantzhaff, in , 2010 Free Fatty Acids Acid Value The acid value, like kinematic viscosity, is a facile method for monitoring fuel quality.
A good coincidence was reported for the experimental results. Peroxide value determination is a standard test for fresh oils, but it has limited value for frying oil quality in use since peroxides not being stable decompose at elevated frying temperatures. Those reactions are accelerated by high temperature and by light and oxygen exposure. So handle the reagent with gloves. So it is important to know the extend to which a fatty acid is unsaturated. Such glass fiber-made paper or cloth for the test paper can be readily prepared by cutting, etc. Objective : To determine the iodine value of fats and oils and thus estimate the unsaturation of the fats and oils.
Particulates are determined by filtering a defined quantity of oil through a filter and comparing the filter disk to acceptable standards. Factors which influence the determination of peroxide values by the iodimetric method have been investigated. Determination of peroxide value Rancidity is brought about by the action of air oxidative rancidity or by microorganisms ketonic rancidity in oil. The method is not suitable for milk fats and is not applicable to lecithins. Two electrons are transferred, resulting in the cleavage of the 0-0-bond and the formation of a hydroxyl group Swern and Silbert, 1963. Martini, in , 2010 14. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.
A precaution that should be observed is to add the starch indicator solution only near the the end point is near when fading of the yellowish iodine colour occurs because at high iodine concentration starch is decomposed to products whose indicator properties are not entirely reversible. Final oil color is determined by a color comparison technique, such as the Lovibond system. It is also applicable to margarines and fat spreads with varying water content. The method is applicable to all animal and vegetable fats and oils, fatty acids and their mixtures with peroxide values from 0 meq to 30 meq milliequivalents of active oxygen per kilogram. Unsaturated fatty acids can be converted into saturated by the process of hydrogenation.
Clostridium acetobutylicum reduced oleic acid to a slight extent at the double bond and at the carboxyl group. Evidence is presented that the hemoglobin free extracts contain at least two principles which may be responsible for the rapid development of rancidity in bacon and one inhibitor. This was also observed by Tovar et al. Two methods for determining strong acids and free fatty acids in one measurement were developed. Polymers content is used as a regulatory index for determining end of fry-life or oil discard point in certain European countries e. The excess acid can be determined by titration against alkali and the epoxide value can be calculated and expressed as mmol epoxide groups per kg of lipids. Reagent test Kits The reagents are packaged in foil pouches containing 10 tubes useful to perform 10 analyses.
Toldrá, in , 2011 20. Nevertheless, the values of free acidity and the peroxide value of the olive oil obtained from partially damaged fruit were not high from an olive oil quality point of view: a maximum acidity of 0. Starch is used as indicator. Although the oil has already been damaged by oxidation, and higher levels of degradation products have already formed, the speed of hydroperoxide decomposition can result in falsely low levels of these compounds. Epoxy derivatives oxiranes , which are formed by reaction of hydroperoxide groups with reactive double bonds, react with excess acids to open the epoxy ring and form hydroxyl derivatives.
In this reaction, iodine monochloride reacts with the unsaturated bonds to produce a di-halogenated single bond, of which one carbon has bound an atom of iodine. The increase in apparent peroxide value observed in earlier iodimetric procedures when the quantity of fat taken for the determination was reduced, has been shown to be due to an increasing error reuniting from further oxidation of the fat by dissolved oxygen during the determination, rather than to a decreasing error due to loss of iodine by re-absorption. Another embodiment of the present invention is as follows: To 100 ml of water is added 2 g of soluble starch, and the mixture is heated and brought to a clear solution. There are also boxes of 100 tests, however, packaged in 10 bags of 10 tubes containing the reagent. The Fe3+ ions resulting from oxidation are grouped and form a red complex.
Since the liberated iodine easily combines with the ambient starch and turns blue in accordance with the quantity of iodine upon subsequent addition of water, determination of the peroxide value, or consequently the edibility, of the oil or fat can be conveniently effected by determinaton of merely finding the intensity of the color developed on the test paper. Headspace air was 5—8% by volume. However, such judgement requires skills and besides is never expected to be accurate. From this value, the propagation step of the free radical chain mechanism and the accumulation of hydroperoxides can be followed. For analysis of olive oil Code. It is to be noted that the peroxide value is a dynamic parameter, whose value is dependent upon the history of the sample.