ELISA for monitoring lipid oxidation in chicken myofibrils through quantification of hexanal-protein adducts.
The objectives of this study were to optimize a monoclonal competitive indirect enzyme-linked immunosorbent assay (CI-ELISA) for hexanal detection, optimize solubilization and alkylation procedures for the formation of hexanal-protein adducts, and compare the ability the CI-ELISA, thiobarbituric acid reactive substances assay (TBARS), and a solid-phase microextraction-gas chromatography-mass spectrometry (GC/MS-SPME) method for monitoring lipid oxidation in freeze-dried chicken protein. Freeze-dried myofibrils with added methyl linoleate (0.6 mmol/g of protein) were stored at 50 degrees C at two water activities (a(w) = 0.30 and 0.75) for 5 days. Hexanal was measured by GC/MS-SPME and CI-ELISA, and malonaldehyde by TBARS. At an a(w) of 0.30, 34.7 and 39.7 microg of hexanal/g of myofibril were detected by GC/MS-SPME and CI-ELISA, respectively, after 4 days of storage. At an a(w) of 0.75, 39.8 and 61.1 microg of hexanal/g of myofibril were detected by GC/MS-SPME and CI-ELISA, respectively, after 4 days of storage. The CI-ELISA was well correlated with the GC/MS-SPME (r = 0.78) and TBARS (r = 0.87) methods. The correlation of the hexanal-specific CI-ELISA to both GC/MS-SPME and TBARS verified the ability of the CI-ELISA to be used as an index of lipid oxidation, offering the convenience for use in a kit to be utilized within a food-processing facility.