Volatiles produced by Staphylococcus xylosus and Staphylococcus carnosus during growth in sausage minces - Part II. The influence of growth parameters

Aseptic model minces inoculated with commercial samples of either Staphyloc occus xylosus or Staphylococcus carnosus were prepared in accordance with a n experimental design investigating the effect of seven parameters: ferment ation temperature, pH, salt, nitrate, glucose, ascorbate, and the access of air. Volatiles produced by the cultures were collected during growth, iden tified and quantified The data were analysed by partial least squares regre ssion. The results showed that oxygen in general had more influence on the aroma producing capacity of Staphylococcus xylosus than of Staphylococcus c arnosus which was more affected by nitrate and glucose. The two strains dif fered mostly with regards to pH. Aroma production by both strains was stron gly related to growth-either positively or negatively depending on compound . potent aroma compounds such as methyl-branched aldehydes and acids arisin g from degradation of leucine, isoleucine and valine, and aromatic compound s arising from phenylalanine were produced in lower amounts when the bacter ia grew well, that is, produced cell mass, whereas the opposite was the cas e for compounds such as sulphides and ketones.