30C-26 |
Modified extraction method for determining 2-thiobarbituric acid values in meat with increased specificity and simplicity |
B. WANG1, A. Benjamin, R. D. Pace, B. Phillips, A. Porobodessai, and W. A. Hill. (1) Food and Nutritional Sciences, Tuskegee University, 204G Campbell Hall, Tuskegee, AL 36088 Lipid peroxidation in cooked meat results in a warmed-over flavor. 2-thiobarbituric acid value (TBA) is often used to indicate the extent of lipid peroxidation. However, many other agents also react with TBA to produce interfering colors, e.g., sucrose often added during meat processing. Although these interfering reactions can be reduced when the reaction is conducted at room temperature, it takes more than 4 hours for the reaction to be complete. This is a severe limitation to a wide application of this method. Our objective was to increase the specificity of TBA value method by changing the reaction conditions for earlier detection. Ground beef was mixed with 5% sucrose and cooked in a 90°C water bath until the internal temperature reached 70°C. A 10 g portion of cooked beef, stored at 4°C for 0, 1, and 7 days, was replicated and homogenized with 90 mL extraction solution. After centrifugation, 2 mL of the supernatant was mixed with 2 mL of 80 mM TBA solution (pH pre-adjusted to 4). The mixture was incubated either at 90°C or 40°C at different times for color development. TBA value was calculated based on malondialdehyde (MDA) content. At 90°C incubation for 20 min, sucrose reacted with TBA producing a yellow color with an absorbance of 0.05. At 40°C incubation, sucrose did not form any detectable interfering color even after 6 hours of incubation. After this modification, the reaction was complete within 90 min and the TBA values in freshly cooked beef and after a 7-day storage were 2.1 and 14.0 nmole/g, respectively. The recovery rate of MDA was between 98-102%. Hence, the modified method was more specific and simple than the original method. This modified method could be used to monitor lipid peroxidation in cooked red meat products containing sucrose.
Session 30C, Muscle Foods: Tenderness, Quality, Processing, Marination, Oxidation, and Shelf-Life
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