Abstract
The use of S-nitrosocysteine (SNC) and S-nitroso-N-acetyl-2,2-dimethylcysteine (SNADC) as curing agents in a comminuted meat patty system was investigated and compared with sodium nitrite. The two S-nitrosothiols were prepared and their stability in brine was established. Colour formation and rate of fading of raw and cooked patties cured with sodium nitrite, SNC or SNADC and stored in the light, in the dark, in vacuum-packs and in air were measured by chemical analysis, by a panel and by a Colorimeter. These techniques showed conclusively that 50 ppm nitrite molar equivalent of SNC and SNADC converted a similar amount of muscle haem pigment into its nitrosyl form and that the pigment produced faded at approximately the same rate as nitrite whilst 12.5 and 25 ppm nitrite equivalent SNC and SNADC formed less colour and faded faster than 50 ppm sodium nitrite. Residual nitrite levels were much lower in S-nitrosothiol cured patties than in those cured with nitrite. However, there was no increased rate of spoilage associated with these low levels of residual nitrite. After selective separation, extraction and concentration, volatile N-nitrosamines were determined by a gas chromatography with a Thermal Energy Analyser a as selective detector. Less N-nitrosamines were formed in patties cured with S-nitrosothiols than those cured with nitrite, however, the difference was not as marked in patties containing additional fat as in those without. Meat pH, over the range used, had no significant effect on N-nitrosamine formation in the patties. Results on animal studies carried out by BIBRA on S-nitrosothiols prepared in bulk in a purified form showed that it was unlikely that they presented a mutagenic hazard at the concentration used in cured meat products. However, it was advised that direct handling of these S-nitrosothiols should be limited by the use of normal protective measures.