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Abstract
This study was aimed to investigate effects of acetic acid (0.5%), ethanol (2%), and NaCl (2%) on the formation of protein-bound Nε-carboxymethyllysine (CML), Nε-carboxyethyllysine (CEL) and their precursors, glyoxal (GO) and methylglyoxal (MGO), in ground pork during commercial sterilization (121 °C, 10 min or 30 min). The commercial sterilization led to significant increases of CML and CEL in pork (raw: CML 2.91 ± 0.72, CEL 9.36 ± 3.22; 10 min heating: CML 15.30 ± 3.58, CEL 21.19 ± 5.70; 30 min heating: CML 40.05 ± 16.41, CEL 101.95 ± 42.24; all in mg/kg protein), regardless of the addition of an additive or not. However, all sterile pork (10 min heating) contained 5–31% less GO and 7–34% less MGO (except for the ethanol treated pork) as compared to their raw counterparts (GO: 2.48–4.65 mg/kg; MGO: 1.12–2.33 mg/kg). The addition of acetic acid led to an average of 33% more CML in sterile pork heated for 10 min in comparison with the control counterparts, but an average of 23% less CML and CEL in sterile pork heated for 30 min. The addition of ethanol or NaCl did not result in any obvious difference in the levels of CML and CEL in sterile pork. The amounts of CML and CEL had no direct relationship with the amounts of their precursors (GO and MGO) in sterile pork, which is possibly due to the high reactivity of the two α-dicarbonyl compounds that could rapidly react with other compounds like lysine to form more stable products (such as CML and CEL) during heating.