Volatiles produced by Staphylococcus xylosus and Staphylococcus carnosus during growth in sausage minces - Part I. Collection and identification

Aseptic model minces were inoculated with commercial samples of either Stap hylococcus xylosus or Staphylococcus carnosus. Volatiles produced by the cu ltures were collected during growth by diffusive sampling onto adsorbent tr aps, identified by thermal desorption-gas chromatography-mass spectrometry and quantified by thermal desorption-gas chromatography-flame ionisation. T he data were analysed by principal component analysis. The study showed tha t both starter cultures produced a large number of volatiles in concentrati ons of sensory importance. Almost all of the major volatiles resulted from amino acid degradation, suggesting that the effect of Staphylococcus starte r cultures on flavour quality is much related to their ability of cataboliz ing amino acids. With the exception of diacetyl, acetoin and 2-ethyl-1-buta nol both cultures formed the same volatiles. Diacetyl and acetoin were not produced by Staphylococcus carnosus and 2-methyl-1-butanol was not produced by Staphylococcus xylosus. The ketones, acetone, 3- and 4-methyl-2-pentano ne, and the two sulphides, dimethyldisulphide and dimethyltrisulphide, were produced in higher amounts by Staphylococcus xylosus, whereas methyl-branc hed, short-chain aldehydes and acids were produced in higher amounts by Sta phylococcus carnosus. 2-Pentanone, aromatic compounds and nitrogen-compound s were produced in similar amounts by both cultures.