摘要 : A microbiological and biochemical characterization of Fossa (Pit) cheese is reported. The cheeses had different methods of production and were made from cow or ewe milk. The total number of mesophilic bacteria and the number of sp... 展开 A microbiological and biochemical characterization of Fossa (Pit) cheese is reported. The cheeses had different methods of production and were made from cow or ewe milk. The total number of mesophilic bacteria and the number of specific microbial groups differed among the cheeses. Lactococci used as starters were found in very low numbers. Non-starter lactic acid bacteria (NSLAB) such as Lactobacillus plantarum, L. curvatus and L. paracasei subsp. paracasei were found in high numbers (5.8-7.8 log c.f.u./g). Cheeses produced from pasteurized or raw milk and using lactococci as starters or not showed similar microbiological and biochemical characteristics. High concentrations of NaCl-in-moisture (11.5%) and a low value of water activity (0.850) negatively influenced the microbial content and proteolysis. The ratio of pH 4.6-soluble N:total N (23.6-39.1%) and the concentration of free amino acids (11.37-41.06 mg/g) were very high and varied with cheeses. Fossa cheeses which contained the highest number of NSLAB also had the highest concentration of amino acids. The principal amino acids were glutamic acid, valine, leucine and lysine. Urea-PAGE electrophoresis of the pH 4.6-insoluble and -soluble fractions differentiated the cheeses. Apart from variations in method of production, reverse-phase-HPLC of the ethanol-soluble fraction showed a peptide profile which was common to all cheeses. Cheeses which had the highest concentrations of free amino acids and the highest number of NSLAB, also containedthe highest aminopeptidase, dipeptidase and iminopeptidase activities. Fossa cheeses also showed a moderate lipolysis which varied among the samples: total free fatty acids ranged from 578 to 1676 mg/kg. The highest concentrations were found independently of the milk used. The principal fatty acids were butyric, caproic, palmitic and oleic acids. Sensory evaluation of the Fossa cheeses showed differences especially related to the extent of proteolysis. 收起