Volatile sulfur compounds produced by probiotic bacteria in the presence of cysteine or methionine

To investigate the abilities of various probiotic bacteria to produce volatile sulfur compounds (VSCs) relevant to food flavour and aroma. Methods and Results: Probiotic strains (Lactobacillus acidophilus NCFM, Lactobacillus plantarum 299v, Lactobacillus rhamnosus GG, Lactobacillus reuteri ATCC55730 and L. reuteri BR11), Lactobacillus delbrueckii ATCC4797, L. plantarum ATCC14917 and Lactococcus lactis MG1363 were incubated with either cysteine or methionine. Volatile compounds were captured, identified and quantified using a sensitive solid-phase microextraction (SPME) technique combined with gas chromatography coupled to a pulsed flame photometric detector (SPME/GC/PFPD). Several VSCs were identified including H₂S, methanethiol, dimethyldisulfide and dimethyltrisulfide. The VSC profiles varied substantially for different strains of L. plantarum and L. reuteri and it was found that L. reuteri ATCC55730 and L. lactis MG1363 produced the lowest levels of VSCs (P < 0·05). Levels of VSCs generated by bacteria were found to be equivalent to, or higher than, that found in commercial cheeses. Conclusions: Several probiotic strains are able to generate considerable levels of VSCs and substantial variations in VSC generating potential exists between different strains from the same species. Significance and Importance of the Study: This study demonstrates that probiotic bacteria are able to efficiently generate important flavour and aroma compounds and therefore has implications for the development of probiotic containing foods.