S-sulfonate determination and formation in meat products

A treatment with cyanide for the analysis of S-sulfonates in meat and meat derivatives, after a study of the effectiveness of this agent and that of dithiothreitol (DTT), is proposed. Once the protein-bound sulfite has been released, it is determined by HPLC ion exclusion with electrochemical detection. In the assay on the reproducibility of the method, standard deviations were 7.4, 9.2, and 11.4 for mean S-sulfonate values of 69, 107, and 130 microg of SO(2)/g, respectively. Mean recovery was 91.2% for different amounts (56, 111, and 223 microg of SO(2)/g) of S-sulfocysteine added. A study was made of the formation of S-sulfonates in model systems and in meat from different species-chicken and beef-with different fat contents. In the assays with meat, two different levels of sulfite addition were used: 600 and 1200 microg of SO(2)/g. From the assays carried out in model systems with sulfite and cystine it may be concluded that one factor limiting the interaction is the accessibility to disulfide groups. The proportion of S-sulfonates in sulfited meat remains relatively constant and does not seem to be governed by the meat component, the level of sulfite addition, or the fat content. However, the latter two factors are inversely correlated with the retention of sulfite in the foods analyzed.