Measurement of Oxidation-Related Changes in Proteins of Freeze-Dried Meats

A new methodology for detection of lipid oxidation in freeze-dried meats, using myoglobin, has been developed. Fresh, cold beef was ground, freeze-dried and stored aerobically at 37°C. Samples, taken at different time intervals, were reconstituted and “meat extract” obtained. Extent of myoglobin insolubilization was determined by absorbance intensity at isobestic point (525 nm). Oxidation of oxymyoglobin to metmyoglobin in meat extract was quantified by measuring α peak intensity of metmyoglobin at 630 nm. Myoglobin polymerization was determined by isolation of myoglobin dimers and monomers from meat extract using gel filtration chromatography. Dimer/monomer ratio was calculated from Soret band absorption intensity at 409 – 415 nm. The three myoglobin-based oxidative indicators correlate well with each other and can be used to detect extent of lipid oxidation in freeze-dried meat products.