Accelerated oxidation peroxide value

Shelf stability test Shelf life is predicted by the active oxygen method (AOM). The fat or oil is subjected to an accelerated oxidation test under standardized conditions so that the signs of deterioration are revealed within several hours or days. The sample is heated at 97.8°C while air is blown through it. The AOM value is reported as the number of hours to reach a peroxide value of 100 meq/kg. 

Shelf Storage Test The test material is stored under similar conditions as in retail and is evaluated for the effectiveness of antioxidants in prolonging the premium quality of the product. Periodic evaluation of the hpid oxidation products (primary or secondary) by chemical tests (e.g., peroxide value, conjugated diene value, 2-thiobarbituric acid reactive substances, hexanal content) or sensory evaluation will be used to find out the onset of oxidation. The main drawback of this kind of evaluation is the time taken therefore, rapid evaluation or accelerated methods are often preferred (19, 51). 

AOM Stability. The active oxygen method (AOM) is the most commonly used analytical method for measuring oxidative stability of fats and oUs products. AOM employs heat and aeration to accelerate oxidation of the oil by continuously bubbling air through a heated sample. Periodic peroxide value analyses are performed to determine the time required for the oil to oxidize under the AOM conditions. This method requires close attention to detail to produce reproducible results, and even then, the variation between laboratories is 25 for a 100-hour AOM sample. 

Many methods have been developed to access the extent of oxidative deterioration, which are related to the measurement of the concentration of primary or secondary oxidation products or of both. The most commonly used are peroxide value (PV) that measures volumetrically the concentration of hydroperoxides, anisidine value (AV), spectrophotometric measurement in the UV region and gas chromatographic (GC) analysis for volatile compounds. Vibrational spectroscopy, because of its high content in molecular structure information, has also been considered to be useful for the fast measurement of lipid oxidation. In contrast to the time consuming chromatographic methods, modem techniques of IR and Raman spectrometry are rapid and do not require any sample preparation steps prior to analysis. These techniques have been used to monitor oil oxidation under moderate and accelerated conditions and the major band changes have been interpreted. ... 

The vapors of methyl acrylate form explosive mixtures with air, over a relatively wide range the LEL and UEL values are 2.8 and 25.0% by volume in air, respectively. Methyl acrylate undergoes self-polymerization at 25°C (77°F). The polymerization reaction proceeds with evolution of heat and the increased pressure can cause rupture of closed containers. The reaction rate is accelerated by heat, light, or peroxides. Vigorous to violent reaction may occur when mixed with strong oxidizers (especially nitrates and peroxides) and strong alkalies. 

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