ABSTRACT
In this study we developed new extraction and detection methods (using HPLC-UV and LC-MS), making it possible to analyze the smoke phenol syringol and its oxidation products nitrososyringol, nitrosyringol, and the syringol dimer 3,3',5,5'-tetramethoxy-1,1'-biphenyl-4,4'-diol, which were identified in heated meat for the first time. Preliminary brine experiments performed with different concentrations of ascorbic acid showed that high amounts of this antioxidant also resulted in almost complete degradation of syringol and to formation of the oxidation products when the brines were heated at low pH values. Heat treatment (80°C) and subsequent simulated digestion applied to meat samples containing syringol, ascorbic acid and different concentrations of sodium nitrite produced 3,3',5,5'-tetramethoxy-1,1'-biphenyl-4,4'-diol even at a low nitrite level in the meat matrix, while nitroso- and nitrosyringol were isolated only after the digestion experiments. Increasing amounts of oxygen in the meat matrix decreased the syringol concentration and enhanced the formation of the reaction products in comparison to the samples without added oxygen.
Subject(s)
Antioxidants/isolation & purification , Pyrogallol/analogs & derivatives , Red Meat/analysis , Animals , Ascorbic Acid/analysis , Biphenyl Compounds , Cattle , Food Handling , Hot Temperature , Hydrogen-Ion Concentration , Meat , Meat Products/analysis , Nitrites/analysis , Nonlinear Dynamics , Pyrogallol/isolation & purification , Salts/chemistry , SwineABSTRACT
In this study we investigated the formation of the oxidation products of guaiacol in brines and heated meat matrix: 6-nitrosoguaiacol, 4-nitroguaiacol and 6-nitroguaiacol. For this purpose we applied a newly developed HPLC-UV and LC-MS method. For the first time, 6-nitrosoguaiacol was determined in brine and meat (containing guaiacol and sodium nitrite), which had been heated to 80°C and subsequently subjected to simulated digestion. Application of 500mg/L ascorbic acid to the brines reduced guaiacol degradation at pH3 and simultaneously inhibited the formation of 6-nitrosoguaiacol compared to brines containing only 100mg/L of ASC. The oxidation products were isolated with a new extraction method from meat samples containing 400mg/kg sodium nitrite at pH3.6 following simulated digestion. When oxygen was added, 6-nitrosoguaiacol was determined even at legally allowed levels (150mg/kg) of the curing agent. Finally, we developed a new LC-MS method for the separation and qualitative determination of the four main smoke methoxyphenols.
