Acid value thiobarbituric

Effect of Nitrite on Thiobarbituric Acid Values and Sensory Scores of Cooked Beef°... 

Ionic Iron Levels in Beef Pigment Extracts, and Thiobarbituric Acid Values Obtained on Heating Extracts with Washed Beef Muscle°... 

Ke, P.J. and Woyewoda, A.D. 1979. Microdetermination of thiobarbituric acid values in marine lipids by a direct spectrophotometric method... 

Pokomy, J. and Dieffenbacher, A. 1989. Determination of 2-thiobarbituric acid value Direct method. Results of a collaborative study and the standardised method. Pure Appl. Chem. 61 1165-1170. 

Pokomy, J., Valentova, H., and Davfdek, J. 1985. Modified determination of 2-thiobarbituric acid value in fats and oils. Nahrung 29 31-38. 

Thiobarbituric Acid Value. The 2-thiobarbituric acid (TEA) test is a popular method for measuring sensory oxidation products. It is based on the formation of a colored complex between two molecules of TEA reagent with one molecule of malonaldehyde or TEA reactive substances (TEARS). This intensity of the pink chromogram is measured at 532 nm. 

The lipoxygenase and peroxidase enzymes also have a negative impact on the oxidative state of the bran (Table 9). Further degradation of the oil occurs as reflected in an increase in peroxide and thiobarbituric acid value and a decrease in iodine value. Both lipoxygenase and peroxidase enzymes are inactivated with lipase inactivation. 

Fig. 6. Effect of oxidized liposome on viability of Meth-A fibrosarcoma cells and macrophage-like J744-1 cells. Data are means SD, n = 6. P< 0.01, P< 0.05 vs. 0 p,g/mL. 2-DHA-PC/PS liposomes, 2-thiobarbituric acid value (TBA-V) = 1.62 0.12 nmol/mL. Soy PC/PS liposomes, TBA-V = 1.02 + 0.01 nmol/mL. See Figure 1 legend for abbreviations.

Abbreviations PC, phosphatidylcholine PS, phosphatidylserine DHA, docosahexaenoic acid TBA-V, 2-thiobarbituric acid value. 

For further affirmation of the data obtained from e-nose analysis of cookies, the conventional biochemical assays such as determination of free fatty acid (FFA) content, peroxide value (PV) and thiobarbituric acid value (TEA) were carried out to estimate the rancidity of different cookie sets during its storage (Table 9). The peroxide value (PV) and free fatty acid (FFA) content of the cookies were determined by... 

When 1, 3, 3-triethoxypropene was hydrolyzed with IN sulfuric acid, a solution of malonaldehyde whose optical density was perfectly stable at 350 m/x for at least one week was obtained. If the solution was made alkaline, the optical density at the same wavelength increased by a small value and then remained virtually constant for at least one week (56). It was also observed that in these solutions the extinction coefficient at 350 m/x was very low (observed 8.3, 61.5 and 69, for solutions of pH 0.4, 7.15 and 9.4 respectively) compared with previously reported values which varied from 200 ( 40) to 1000 ( 48). On the other hand, the absorption of solutions having a pH of 3 to 5, increased considerably with time (at pH 4.75, the extinction coefficient of malonaldehyde at 350 m/x was initially about 40 after four weeks a value of about 930 was recorded and the optical density of the solution was still increasing). This increase in absorption was accompanied by a marked decrease in the malonaldehyde content of the solution, as measured by the thiobarbituric acid method. As a corollary, it was found that aqueous solutions of malonaldehyde, prepared by autocatalyzed hydrolysis (33) of the same acetal and which had a pH of about 3.5, showed, at the completion of the hydrolysis, considerably higher extinction coefficient values at 350 m/x than did those malonaldehyde solutions which were prepared by hydrolysis with IN acid and subsequently adjusted to pH 4. It appears, therefore, that at pH values at which most of the periodate oxidations are carried out, malonaldehyde is unstable and undergoes a chemical reaction, the nature of which is not, as yet, known. 

Dopamine, a strong water-soluble antioxidant, was identified in banana fruit (Musa cavendishii) by Kanazawa and Sakakibara (2000). Banana fruit contained high levels in the pulp and peel 2.5-10 mg/100 g and 80-560 mg/100 g, respectively. A banana water extract was reported to suppress the autoxidation of linoleic acid by 65-70% after a 5-day incubation in an emulsion system, as determined from peroxide value and thiobarbituric acid reactivity (Kanazawa and Sakakibara 2000). 

Figure 5. Inhibitory effect of NO on Fe -induced lipid peroxidation. Shown is the decreased generation of an oxidative marker (thiobarbituric acid reactive substances, TBARS) as a result of 0.9 iM NO. HL-60 cells (5 x loVral) were placed in an O2 monitor and at the designated time points, butylated hydroxytoluene was added and samples were quick frozen for determination of TBARS. The values represent the mean and standard error of 3-5 independent determinations. Also shown for comparison is the residual concentration of O2 after exposure to the the same conditions. This shows a decrease in utilization of O2 in the presence of NO. We conclude that NO reduces TBARS, and the percent inhibition is similar to the poeent inhibition of O2 consumption. (Modified from our data in Kelley, E.E., Wagner, B.A., Buettner, G.R., and Bums, C.P., 1999, Arch. Biochem. Biophys. 370 97-104).

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. 

Secondary oxidation products oxidation indices, 656, 665-72 acid value, 672 anisidine value, 656, 666 carbonyl compounds, 656, 669-71 conjugated dienes value, 671-2 thiobarbituric acid reactive substances, 656, 666-9... 

TBA, 2-thiobarbituric acid reactive substances, mg MDA/kg sample CBB, cooked beef/brothy, all sensory values are mean intensity scores BM, beefy/meaty BRO, brothy BRC, browned/caramel SWT, sweet PTY, painty CBD, cardboardy SUR, sour BTR, bitter. 

Rancidity measurements are taken by determining the concentration of either the intermediate compounds, or the more stable end products. Peroxide values (PV), thiobarbituric acid (TBA) test, fatty acid analysis, GC volatile analysis, active oxygen method (AOM), and sensory analysis are just some of the methods currently used for this purpose. Peroxide values and TBA tests are two very common rancidity tests however, the actual point of rancidity is discretionary. Determinations based on intermediate compounds (PV) are limited because the same value can represent two different points on the rancidity curve, thus making interpretations difficult. For example, a low PV can represent a sample just starting to become rancid, as well as a sample that has developed an extreme rancid characteristic. The TBA test has similar limitations, in that TBA values are typically quadratic with increasing oxidation. Due to the stability of some of the end-products, headspace GC is a fast and reliable method for oxidation measurement. Headspace techniques include static, dynamic and solid-phase microextraction (SPME) methods. Hexanal, which is the end-product formed from the oxidation of Q-6 unsaturated fatty acids (linoleate), is often found to be a major compound in the volatile profile of food products, and is often chosen as an indicator of oxidation in meals, especially during the early oxidative changes (Shahidi, 1994). 

SPME solid-phase microextraction SV saponification value TA titratable acidity TBA thiobarbituric acid TBARS thiobarbituric acid-reactive substances... 

Although other natural sugars were tested as possible alternate substrates the specificity for KDO was absolute. However, the nucleotide CTP could be replaced by deoxy-CTP as a nucleotide acceptor when the reaction was carried out at both pH 8.0 and pH 9.5. Also, UTP was an effective nucleotide acceptor when the reaction was carried out at pH 9.5 but much less so when tested at pH 8.0. No other nucleotide tested acted as a substrate or inhibited the formation of the NaBH,-resistant thiobarbituric acid positive reaction. The apparent K values.determined at.pH 9.5 for CTPdeoxy-CTP and UTP were fto x 10 4 M, 3.4 x 10 M, and 8.8 x 10 M, respectively. Th apparent V values for CTP,... 

Blue, chosen because it s absorption was peaked at 620 nm and because it had a deep absorption minimum around 450 nm. In later work, a thiobarbituric acid derivative in PMMA produced an efficiency of 39 % W 1 cm-2 over an estimated 32 pm absorption length [62]. This was followed recently with new tricyanovi-nylaniline doped polymers in which a net efficiency of nearly 250% W 1 cnr2 was demonstrated over 35 pm. [63] An added bonus was that this approach proved to be the stimulus for many materials to be characterized. Materials with p[3 values as large as 3,800x10 48 esu, coupled with good transparency in the 450-470 nm window, were synthesized and optimistically predicted to satisfy criteria for ADPM SHG with target efficiencies of about 2000% W 1 [64] ... 

TBA value Formation of malonaldehyde on oxidation of lipids and its reaction with 2-thiobarbituric acid Gray456... 

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

In a study on butteroil held at a temperature ranging from —10 to +50°C, oxidation rate increased with increasing temperature but the same flavor was formed on storage and the reaction sequence for flavor formation was similar at all temperatures (Hamm et al., 1968). Dunkley and Franke (1967) reported a decrease in flavor intensity and thiobarbituric acid (TBA) values in liquid milk as storage temperature was increased from 0 to 4 to 8°C. Schwartz and Parks (1974) reported that condensed milk stored at — 17°C was more susceptible to oxidized flavor development than at — 7°C. 

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