Validation of thiobarbituric acid reactive substances (TBARS) method for measuring secondary lipid oxidation products in fresh Indian mackerel (Rastrelliger kanagurta)

Abstract

The measurement of thiobarbituric acid reactive substances (TBARS), such as malondialdehyde (MDA), has been used as an indicator of lipid peroxidation. The TBARS method developed in this study was validated according to the guidelines set by the International Conference on Harmonisation (ICH), International Union of Pure and Applied Chemistry (IUPAC) and EURACHEM. The validation criteria included assessing linearity, limit of detection (LOD), limit of quantification (LOQ), recovery, repeatability, and uncertainty. To evaluate the quality changes in Indian mackerel (Rastrelliger kanagurta), the fish was placed in a refrigerator (4 °C) for six days. The sensory evaluation, TBARS and Total Volatile Base Nitrogen (TVBN) method were used to assess the quality changes at 48 h interval. The TBARS method validation results showed that the linearity range was 0.3–6.5 µmol/L. The calibration curve demonstrated a linear relationship between absorbance and concentration, with a coefficient of correlation 0.9999. The regression equation for the curve was Y = 0.1337X + 0.0905. The LOD and LOQ were determined to be 0.1 μmol/L and 1.5 μmol/L, respectively. The repeatability (% RSDr) was found to be 1.6. The percentage recoveries for MDA were calculated at three concentration levels and results was observed from 85.95% to 86.98%. The expanded uncertainty was within ± 5.18% (k = 2; 95% confidence interval). The TBARS method showed a high correlation coefficient 0.983 with storage time, indicating a strong relationship between TBARS value and freshness. Similarly, the sensory evaluation showed a correlation coefficient of 0.996 with storage time, indicating a high agreement between sensory evaluation and freshness. The TVBN method exhibited a correlation coefficient of 0.957 for chilled Indian mackerel. In conclusion, the developed TBARS method is suitable for measuring malondialdehyde as a quality parameter in assessing the freshness of tropical water fish.