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[Display omitted] • Nitrite, nitrate, and hydrogen peroxide were the main ROS/RNS in PAW. • PAW treatment reduced the MDA content in tuna muscle. • The reaction of nitrite in PAW with MDA during its measurement processes reduced the MDA content. • Nitrite in PAW cannot react with MDA during the storage period of tuna muscle. An interesting phenomenon that plasma-activated water (PAW) treatment reduced the malonaldehyde (MDA) content in muscle foods was observed in both previous reports and the present study. However, the mechanism remains unclear. To clarify the theoretical basis of this phenomenon, the main reactive components in PAW were determined, and the changes in the fatty acid profile in tuna muscle after PAW treatment were analyzed. The results showed that the MDA content reduction upon PAW treatment was not due to the inhibition of lipid oxidation. To mimic the possible reaction of the components in PAW with MDA, individual hydrogen peroxide, nitrite, and nitrate or their mixture solution were added into MDA standard and tuna muscle. The results showed that the reaction of nitrite in PAW with MDA occurred during its measurement processes caused its reduction. The results in this work fully explained why PAW treatment reduced the MDA content in muscle foods. [ABSTRACT FROM AUTHOR]

Abstract: Cod liver oil was oxidized with Fenton-like systems containing transition metals Fe(II), Cr(II), Pb(II), and Cd(II). Malonaldehyde (MA) formed from 10μl cod liver oil oxidized by a Fenton-like system containing each metal at levels of 0.25, 0.5, 1 and 4μmol was analyzed by a gas chromatograph equipped with a nitrogen phosphorus detector. The MA production exhibited dose response and the greatest amount (837.0±19.1nmol) was obtained by the Fe(II) system at the level of lμmol. Generally, higher MA formation is observed in the lower the third ionization potential of the metal. The decreasing order of MA formed in the metal systems at the level of 1μmol is Fe(II)>Cr(II)(274.1±20.1nmol)>Pb(II)(150.7±13.0nmol)>Cd(II)(95.4±6.7nmol). The amounts of MA formed in Cr(II), Pb(II), and Cd(II) systems were considerably lower than those in the Fe(II) system. The relative formations of MA in the Cr(II) and Pb(II) systems were similar to those in the Fe(II) system. The results suggest that trace amounts of metals contribute oxidative effects to lipid peroxidation followed by various diseases. [Copyright &y& Elsevier]

Abstract: The effect of Centella asiatica extract and powder in reducing oxidative stress in SpraqueDawley rats was evaluated. Lipid peroxidation was monitored by measuring malonaldehyde (MDA) level in blood. Activities of free radical-scavenging enzymes (superoxide dismutase and catalase) were determined using H2O2 decomposition and nitrobluetetrazolium reduction, respectively. Results showed that administration of H2O2 (0.1%) in drinking water of the rats, for 25 weeks, increased the malonaldehyde levels in erythrocytes of all the rats. However, rats receiving C. asiatica extract, powder and α-tocopherol had lower MDA levels than did the other rats, which indicates, decrease lipid peroxidation in these rats. Increase in catalase activity of the rats appears to be a response to H2O2 accumulation. The decrease in the activity of superoxide dismutase in C. asiatica- and α-tocopherol supplemented rats suggested a lower requirement for the enzyme and this indicates the protective effect of the plant in combating oxidative stress undergone by the rats. Results revealed that C. asiatica extract and powder may ameliorate H2O2-induced oxidative stress by decreasing lipid peroxidation via alteration of the antioxidant defence system of the rats. [Copyright &y& Elsevier]

Malonaldehyde (MA) in gamma-irradiated apple juice was measured using a GC–MS method and in comparison to the thiobarbituric acid (TBA) assay. The profiles of MA content as a function of radiation dose were similar using both methods, however, MA content was higher when measured with the TBA assay compared to the GC–MS method. The overestimation of MA using the TBA assay increased as the amount of MA decreased. Use of the GC–MS method demonstrated MA content in irradiated juice declined rapidly during storage at 5 °C. MA content appeared to decrease much less when the TBA assay was used. The GC–MS method also allowed measurement of formaldehyde and acetaldehyde in addition to MA. [Copyright &y& Elsevier]