HPLC-MS/MS method for the simultaneous determination of lysine-derived markers for protein carbonylation in meat

Changes in Novel Biomarkers for Protein Oxidation in Pork Patties under Different Cooking Methods

“…In the present study, the formation of AAS was observed to be affected by internal temperatures and the interaction between the cooking method and internal temperature (Table 1 and Figure 6). The fresh patties contained 0.02 nmol/mg protein AAS, which was similar to those reported previously [15,32]. Irrespective of cooking methods, the AAS formation increased gradually with internal temperatures, and the highest values were observed in pork patties when the internal temperature reached 90 • C. Consistently, increases in AAS formation were also reported in pork treated with higher temperatures and longer times compared to raw meat [33].…”

“…Afterward, 2 mL of 10% trichloroacetic acid (TCA) was added to the pellets, mixed, and centrifuged at 1200× g for 5 min (4 °C). Afterward, the total protein carbonyls were determined according to the DNPH method of a previous study [15]. Briefly, 0.4 mL of the protein pellets dissolved in 5% SDS were For each cooking method, the heating rates and cook values were calculated.…”

“…Protein solutions obtained from Section 2.4 were diluted to 2 mg/mL, and the AAS and LNL contents were determined using the method described previously with small modifications [15]. In brief, precipitated proteins were dissolved in MES-SDS solution (4-morpholineethanesulfonic acid, 1% SDS, 1 mM DTPA, pH 6.0).…”

“…Moreover, this method has also been criticized for its non-specificity since it is limited to revealing information about the chemical structure and the mechanism of the formation of protein carbonyls [13]. Under this context, α-aminoadipic semialdehyde (AAS), an oxidative deamination product of lysine residues, has been highlighted as a novel, reliable, and more specific biomarker for protein oxidation in recent decades [14,15]. Besides AAS, lysinonorleucine (LNL), a Schiff base-type protein cross-link could also be used as a potential and specific biomarker to indicate the level of protein oxidation, and its quantification method has also been established recently [15].…”

“…Under this context, α-aminoadipic semialdehyde (AAS), an oxidative deamination product of lysine residues, has been highlighted as a novel, reliable, and more specific biomarker for protein oxidation in recent decades [14,15]. Besides AAS, lysinonorleucine (LNL), a Schiff base-type protein cross-link could also be used as a potential and specific biomarker to indicate the level of protein oxidation, and its quantification method has also been established recently [15]. The analysis of these novel biomarkers would increase our understanding of the chemical mechanism and pathways of protein oxidation under different cooking methods.…”