Studies on precursors of chloroform formed in cabbage by sodium hypochlorite treatment

Gel filtration of cabbage treated with sodium hypochlorite (NaClO) affords a fraction showing a high level of chloroform (CHCl3), and this was studied to identify the precursors of CHCl3. The mass spectral ion peaks of the fraction obtained by LC/MS suggested the presence of five kinds of amino acids. Furthermore, analysis of amino acid s by HPLC revealed eight kinds of amino acids including those detected in L C/MS. The concentrations were 48.3 mu g/mL for L-glutamine and less than 10 mu g/mL for other amino acids. An amino acid standard solution prepared wi th amounts similar to those in the fraction was treated with NaClO for 24 h ours. The consequent CHCl3 formation was 82.0% of that formed from the frac tion. In particular, L-alanine contributed a great deal to the formation of CHCl3, while L-glutamine formed little CHCl3. Thus, L-alanine constituents identified in the gel filtration fraction are considered to be the major p recursors of CHCl3 formed in cabbage by NaClO treatment. This result is dif ferent from the previously reported findings on CHCl3 precursors of soybean sprouts.