Effects of sodium bicarbonate and sodium phosphates on the formation of advanced glycation end-products in minced pork during cold storage

This study was to understand the formation of protein-bound Nε-carboxymethyllysine (CML) and Nε-carboxyethyllysine (CEL) in raw minced pork during cold storage (0 °C, 1–7 d) as affected by the addition (0.5% w/w) of sodium bicarbonate (SB), sodium tripolyphosphate (STPP) and tetrasodium pyrophosphate (TSPP). The mean levels of TBARS (P= 0.004), the intensity of tryptophan fluorescence (P= 0.000), and TCA-soluble peptides (P= 0.006) in minced pork were significantly affected by the storage duration, implying the occurrence of lipid oxidation, protein oxidation, and protein hydrolysis in minced pork during the storage. However, the storage duration of minced pork in general did not greatly affect their CML and CEL levels. In addition, the average of CML levels (control 1.00 ± 0.53 mg/kg, SB 1.04 ± 0.54 mg/kg, STPP 0.93 ± 0.47 mg/kg, TSPP 0.94 ± 0.48 mg/kg) in minced pork was not affected by the addition of alkaline salt, but all alkaline salt treated pork had higher levels of CEL (control 3.00 ± 0.64 mg/kg, SB 3.79 ± 0.80 mg/kg, STPP 3.92 ± 1.03 mg/kg, TSPP 4.58 ± 0.94 mg/kg) than their control counterparts without alkaline salt. The promoting effects of alkaline salts for CEL formation were not directly tied to their effects on the pH, TBARS, the intensity of tryptophan fluorescence, and TCA-soluble peptides of minced pork.