Effects of starter cultures on the biochemical characteristics of French dry sausages.

Bacterial starter cultures, consisting of lactic acid bacteria (Lactobacillus, Pediococcus) and staphylococci (Staphlylococcus carnosus. S. saprophyticus, S. warneri), have an important effect on the pH, lactate, acetate and free fatty acid contents of sausages. Sausages made with L. sake had the lowest pH whereas no change of pH was noticed in the controls and in the sausages inoculated with P. acidilactici. Inoculation of S. saprophyticus led to sausages with a high acetate content. Lipolysis occurred not only in inoculated samples but also in the controls, but it was the highest in the sausages inoculated with S. warneri.

Purification and characterization of extracellular Staphylococcus warneri lipase.

The extracellular lipase of Staphylococcus warneri was secreted as a protein with an apparent molecular mass of 90 kDa. It was then sequentially processed in the supernatant to a protein of 45 kDa. Tryptic digestion of the crude extract resulted in a homogeneous sample containing only the 45-kDa form. Purification was achieved by hydrophobic chromatography. Purified lipase had an optimum pH of 9.0 and an optimum temperature of 25 degrees C. The enzyme was stable within the range pH 5.0-9.0; it had a broad substrate specificity. The results of inhibition studies were consistent with the view that lipases possess a serine residue at the catalytic site.