According to AOCS CD 8b (Peroxide Value Acetic Acid-Isooctane Method); ISO (Animal and vegetable fats and oils. SAMPLING AND ANALYSIS OF COMMERCIAL FATS AND OILS AOCS Official Method Cd 8b Revised Peroxide Value Acetic. AOCS has standardized a method for. PV determination with chloroform (Cd. 8- 53) and with isooctane (Cd 8b). The latter method uses a mixture of acetic.
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Plant oils are a good source of compounds that decrease the risk of some diseases. Acetic acid in the pure state is moderately toxic by ingestion and inhalation.
AOCS CD 8b – 90 Peroxido – Free Download PDF
It is toxic by ingestion and inhalation. The blank titration must not exceed 0. Swirl to dissolve the sample. Erratic results reported for this method, especially at higher peroxide values, appear to be related to the isooctane floating on the surface of the aqueous layer References, 3.
Fresh indicator must be prepared when the end point of the titration from blue to colorless alcs to be sharp.
AOCS CD 8b – 90 Peroxido
It is toxic by inhalation and has anesthetic properties. The strength of the sodium thiosulfate solution is expressed in terms of its normality. Proceed as directed in Procedure for Fats and Oils, paragraphs 1—4.
The TLV is 10 ppm in air. Add 1—2 mL of starch indicator and continue the titration, adding the thiosulfate solution slowly until the blue color cr disappears.
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Test for sensitivity—Place 5 mL of starch solution in mL of water and add 0. Rapid mechanical stirring e. The TLV in air is 10 ppm.
The sample must be clear and brilliant. Potassium iodide KI solution—saturated, prepared fresh each day 9 is performed by dissolving an excess of KI in recently boiled distilled water about Continue the titration until the yellow iodine color has almost disappeared.
Continue the titration until the yellow iodine color has almost disappeared. Add 1—2 mL of starch indicator and continue the titration, adding the thiosulfate solution slowly until the blue color just disappears. A report aoca a coulometric method for the measurement of peroxide value References, 2 indicates that the iodide—peroxide reaction is complete at the end of 1 min, and that the liberation of iodine is affected by light.
Fresh indicator must be prepared when the end point of the titration from blue to colorless fails to be sharp. Swirl to dissolve the sample.
If stored under refrigeration, the starch solution should be stable for about 2—3 weeks. This method is highly empirical, and any variation in the test procedure may result in variation of results. The nutritional quality indexes were also calculated.
It is nonflammable, but will burn on prolonged exposure to flame or high temperature. Starch indicator solution—tested for sensitivity, prepared by making a paste with 1 g of starch see Notes, 1 and a small amount of cold distilled water. Do not reheat for filtration unless absolutely necessary. Page 2 of 2.
Please copy and paste this embed script to where you want to embed Embed Script. When completely melted, remove the sample from the hot plate or oven and allow to settle in a warm place until the aqueous portion and most of the milk solids have settled to the bottom.
Titrate with sodium thiosulfate solution, shaking continuously until yellow color has almost disappeared. Erlenmeyer flasks—with glass stoppers, mL. Starch indicator solution—tested for sensitivity, prepared by making a paste with 1 g of starch see Notes, 2 and a small amount of cold distilled water.
If a blue color is formed that requires more than 1 drop of 0. A properly operating fume hood should be used when working with this solvent. The following are suitable starches: