Suitability of thiobarbituric acid method for assessing lipid oxidation in pork, osmotically dehydrated in sugar beet molasses

Abstract

Thiobarbituric acid (TBA) reaction for measuring secondary lipid oxidation products, was evaluated for interferences by ingredients of sugar beet molasses, used for osmotic dehydration. Pork meat was dehydrated in molasses solution and stored for 105 days at 4°C, under the modified atmosphere conditions, or under the atmospheric conditions at 4°C and 20°C for 30 days. The effectiveness of different TBA methods was measured by aqueous acid extraction method (EM) under different conditions of incubation: 1) boiling or 2) room temperature, with 20 mM TBA, and 3) at 40°C, with 80 mM TBA. The distillation TBA method (DM) was employed to evaluate the interferences found in EM, and low TBA values were obtained in all TBA method procedures. Primary lipid oxidation products were, also, low, except for microbiologically contaminated samples with increased water activity value, where elevated peroxide values, but low TBA values were obtained. The data are suggestive of oxidative stability of osmotically dehydrated pork meat under storage in modified atmosphere and refrigerated conditions. TBA EM may be the inadequate method for the analysis of oxidative deterioration of meat samples dehydrated in sugar beet molasses, due to interferences which cause erroneously high value of TBA, detected as absorption at: max. 350 nm and 450-460 nm, present in dehydrated meat and sugar beet molasses itself, which are overlapping the pink peak (max. 532 nm), characteristic for malondialdehyde. TBA EM procedure at low incubation temperature (40°C), and elevated TBA concentration (80 mM), was the most sensitive of analyzed TBA methods.