SOLID-PHASE ACID-EXTRACTION IMPROVES THIOBARBITURIC ACID METHOD TO DETERMINE LIPID OXIDATION

Samples (110g) of raw (17.2-22.6% fat) and cooked 12.6-16.4% fat) ground beef in plastic cups were stored aerobically at 4 +/- 1-degrees-C. Lipid oxidation was measured by four versions of the thiobarbituric acid (TBA) test, including aqueous acid extraction-C18 (TBA-C18), direct heating, distillation, and unmodified aqueous acid extraction; and by sensory evaluation of rancid odor after 0, 2, 4, 6, and 8 days storage. The TBA-C18 method was more specific (P<0.05) and its limit of determination was 20 times lower than the other methods in detecting malonaldehyde. Results correlated (r=0.856 to 0.883 in raw, and r=0.936 to 0.981 in cooked meat) with sensory evaluation scores.