Anisidine/value/test

Determination oe Secondary Oxidation Products ("Oee-Feavor" Voeatiees) 12.2.2.1 p-Anisidine Value Test... 

Other indices measure a secondary stage of oxidation, such as the anisidine value (ANV), pointing to formation of carbonyl compounds, capable of undergoing condensation reactions with p-anisidine, and the thiobarbituric acid reactive substance (TBARS) pointing to the presence of malondialdehyde (MDA) in particular. In biological systems, TBARS is of widespread use as a measure for the extent of oxidation damage. Another test for stability of oils to oxidation is based on the development of acidity as secondary product, for example, standards using the Rancimat equipment or a similar setup. 

Peroxide value, anisidine value and thiobarbituric acid test... 

Other traditional methods available for monitoring the extent of lipid oxidation include the Anisidine value, the Kreis test (Mehlenbacher, 1960), methods based on the carbonyl content of oxidized fats (Henick et al., 1954 Lillard and Day, 1961), and measurement of oxygen uptake either by manometry or polarography (Tappel, 1955 Hamilton and Tappel, 1963). 

Active Oxygen Method for Fat Stability (AOM) (Cd 12-57) determines the time (in hours) for a sample of fat or oil to attain a predetermined peroxide value (PV) under the conditions of the test. The method is used to estimate the comparative oxidative stability of fats and oils. The method has been placed in surplus, in favor of Cd 12b-92 (Oil Stability Index), but retains official status and is still used in domestic industry. p-Anisidine Value (AV) (Cd 18-90) determines the amount of aldehydes (principally 2-alkenals and 2,4-dienals) in animal and vegetable fats and oils. These are degradation products of peroxides, which are not removed by bleaching. Some fats and oils chemists propose increased use of this method in purchase specifications. Bleaching Test for Soybean Oil (Cc 8e-s63) determines the color of a sample of soybean oil after treatment with a specified bleaching earth. Specific methods exist for other oil species. 

Despite it limitations, the TBA test provides an excellent means for evaluating lipid oxidation in foods, especially on a comparative basis. However, its use in bulk oils is less common than the so-called para-anisidine value (p-AnV) detailed below. 

Although the work just described used canola oil, similar increases in free fatty acid levels as a consequence of higher bleach temperatures have been reported for soya (118) and pahn (86, 119) oils. The latter workers also reported decreased peroxide values but increased anisidine values as bleach temperature was increased. This conforms to expectation because the anisidine test is diagnostic for shorter chain aldehydes (including alkenals and dienals), which are secondary oxidation products of peroxide decomposition. 

Wang and Johnson (2001) reported on test measurement methods that were major indicators of soybean oil quality. These tests included peroxide value, anisidine value, FFA content, phospholipid content, total tocopherol content, oxidative stability index, color, and moisture content. For soybean meal, they reported on urease activity, protein dispersibility index (PDI), rumen bypass or rumen undegradable protein, trypsin inhibitor activity, moisture content, residual oil content, protein content, fiber content, color, amino acid profiles, and protein solubility under alkaline (KOH) conditions. 

The anisidine value measures aldehydes, which are not easily decomposed. Thus, the test to determine the anisidine value is more meaningful than that to determine the peroxide value. 

The extent of prior oxidative activity in a fat sample may be estimated by the following peroxide value (PV), thiobarbituric acid test (TEA) (which measures the presence of malonaldehyde), anisidine value—Totox, Kreis test, oxirane test, total and volatile carbonyl... 

In a simple test, such as benzidine, anisidine or heptanal values, the volatile aldehydes are not separated from fat or oil, rather the reaction with the group-specific reagents is carried out in the fat or oil. In addition to the odorous aldehydes, the flavorless oxo-acylglycerols and oxo-acids can be... 

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