ISSN:
1750-3841
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
,
Process Engineering, Biotechnology, Nutrition Technology
Notes:
Malonaldehyde occurs mainly as the enol form (CHOH = CHCHO) in aqueous solution. The UV absorption spectrum of the compound is pH-de-pendent. Below pH 3.0, the compound is s-cis, planar, having an intramolecular H bond, with absorption maximum at 245 mμ and molar absorptivity (ε) = 1.34 × 104. Above pH 7.0, the compound is completely dissociated and the maximum absorption of the enolate anion occurs at 267 mμ with e = 3.18 × 104. The absorbance difference between acidified and basified malonaldehyde solutions at 267 mμ can be used as a measure of malonaldehyde even in the presence of other compounds that absorb in this spectral region, provided their absorption is not pH-dependent. This difference is directly proportional to malonaldehyde concentrations from 5 × 10-6M to 3 × 10-5M. The method has been successfully applied to the assay of malonaldehyde in distillates from rancid foods. Its sensitivity is only about 40% of the 2-thiobarhituric acid (TBA) test, but is sufficient to detect threshold levels of rancidity. The test is simpler, much more rapid, and more specific than the TBA test.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2621.1963.tb01666.x
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