Lipid peroxidation inhibitory assay

The extent of lipid oxidation was determined using thiobarbituric acid reactive substances (TBARS). Thiobarbi-turic acid (TBA) reacts with malonaldehyde bis (dimeth-yl acetal) (MDA) in acidic conditions to form a pink MDA-(TBA)₂ complex, which can be quantified at 532 nm by a spectrophotometer (Sochor et al., 2012). A portion (5 g) of ground shrimp was homogenized with 10 mL of TCA (7.5%, w/w). The mixture was filtered, the filtrate was mixed with an equal volume of 0.02 M TBA and incubated at 100°C for 15 min. The absorbance at 532 nm was measured with Hitachi UH-530 spectrophotometer (Hitachi, Ltd.). TBARS values were calculated from the calibration curve built at concentrations from 0.01 to 0.05 μM and reported as malondialdehyde equivalents (mgMAD/kg of shrimp).