TBA-reaction

TBA reactivity is thus a reflection of the total amount of MDA, / -unsaturated aldehydes, cyclic peroxides and contaminants present in the sample and in the basic form, the reaction is clearly not specific for any one class of peroxidation product (Kosugi and Kugawa, 1986). However, as a first approximation, measurement of tissue fraction oxidation it can be a useful method because it is quick and easy. Great care must be exercised in the interpretation of the results. 

MDA MDA is prepared from the acetal by acid hydrolysis. A solution containing 0.1 mmol 1,1,3,3-tetraethoxy- or methoxypropane in 50 ml water and 0.1 ml, 0.1 M HC1 is warmed at 50°C for 1 hour and 

by the use of double wavelength measurements to increase the assay specificity and 

by preparation of a standard curve using free MDA (Uchiyama and Mihara, 1978). 

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Dahle, L.K., Hill, E.G. and HoUman, RT. (1962). The TBA reaction and the autoxidation of polyunsaturated fatty acid methyl esters. Arch. Biochem. 98, 253-259. 

Charon and Szabo17 demonstrated that chromophore 4 may be produced to a significant extent from a 5-O-substituted derivative of KDO (which does not contain a free diol grouping at C-4-C-5). These authors synthesized 3-deoxy-5-0-methyl-2-octulosonic acid (7 configuration at C-5-C-7, arabino at C-4, unknown) by the Comforth reaction18,19 from 4-0-formyl-2-0-methyl-D-arabinose (see Scheme 4 and Section IV,1). Compound 7 gave a millimolar extinction coefficient of 13 in the TBA assay (as compared to 92 5 for KDO). Based on this result, Charon and Szabo17 formulated for the TBA reaction of 5-0-... 

Perform TBA reaction and measure absorbance (steps 7 to 11) using the three TMP-spiked samples (step 15) and the three TMP dilutions (step 16). 

Perform TBA reaction on 5 ml distillate and measure absorbance (see Basic Protocol 1, steps 7 to 11), but prepare the reagent blank in water instead of TCA reagent/water, and increase heating time to 45 min. 

Guillen-Sans, R. and Guzman-Chozas. M. 1998. The thiobarbituric acid (TBA) reaction in foods A review. CRC Crit. Rev. Food Sci. Nutr. 38 315-330. 

The TBA test is perhaps the most widely used method for determining lipid peroxidation. The representative adduct of lipid peroxidation, malondialdehyde, forms a 1 2 adduct with TBA that can be measured by spectroscopy or fluorometry. The general procedure, of which there are numerous variations, simply involves heating a small quantity of the test substance for a defined period of time in an aqueous acidic solution of TBA, and then measuring the absorbance (535 nm) of the red color which is produced in the TBA reaction. It should be considered as an index of oxidative stress that represents primarily lipid peroxidation. ... 

As early as 1951 (20), and numerous times since then, TBA has been used to measure MA levels in foods. However, TBA should be used to measure extent of lipid oxidation in general, not to quantify MA specifically. At the present time there are numerous substances known to interfere with the TBA reaction. Dugan (21) showed that sucrose and some compounds in wood smoke react with TBA to produce a red color. A yellow pigment found by Yu and Sinnhuber (22) was able to significantly affect the TBA method however, it could be separated by chromatography. Saslaw et al. 

Other aldehydes which produced a positive TBA reaction, including... 

Though widely used, the TBA reaction is not entirely satisfactory as a procedure for assessing oxidation levels. This is indicated, in part, by the frequent modification of the analytical method. A chromatographic technique for specifically measuring propanedial at... 

Although the free iron is catalytically active, the relative importance of protein-bound iron is being debated. Lipid oxidation in cooked meat is not only attributed to changes in iron distribution by protein denaturation and the release of catalytically active non-heme iron, but also to the disruption of cell membranes in meat that brings the polyunsaturated hpids in close contact to the catalysts. Unfortunately, in many studies using the TBA test to determine the effects of different forms of iron on lipid oxidation in meats, the results must be interpreted with caution, because the TBA reaction is significantly affected by iron and other metals, and is subject to serious interference by other factors. In addition to products of lipid oxidation, TB ARS are also formed from proteins and nucleic acids and other non-lipid components in meat tissues that confound the results of the TBA test. 

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