The role of yeasts during the ripening of salami

[摘要] Yeasts play a substantial role in the processing of salami, being present at highnumbers during the ripening stages contributing to aroma and flavour development.Accordingly, the yeasts occurring as natural microflora in commercial salami werequantified, isolated and identified according to conventional identification andenumeration techniques. Depending on conditions, the yeasts grew to maximumpopulations of 107duIg during the ripening stages.Characterization of the naturally contaminating yeasts of commercial salami revealed108 yeast species, belonging to 12 genera. The yeasts most frequently isolated werefrom the genera Debaryomyces, Rhodotorula, Bul/era, Candida, Cryptococcus,Trichosporon and Schwanniomyces in that order. Low appearances of Pichia,Galactomyces, Sporobolomyces, Sterigmatomyces and Torulaspora were observed.Debaryomyces hansenii, Rhodotorula mucilaginosa, Bul/era variabilis and Cryptococcusalbidus were established as representing the typical yeast community associated withsalami. These species were frequently isolated from the meat, during processing andmaturation. The most frequently isolated yeast species, was D. hansenii, isolated onevery sampling occasion.The isolated yeasts were examined based on relevant key properties that governedtheir growth and survival in fermented meat, and proposed as representative selectivecharacteristics to determine a good starter culture. All the yeasts were tolerant to 4-8%NaCl and 80-240ppm nitrite. All the yeasts proved to be non-proteolyic with theexception of Trichosporon beigeli~ whereas lipolitic activity appeared variable.Two predominating yeast isolates, Debaryomyces hansenii and Debaryomycespolymorphus, exhibited relevant qualities regarding fermentation of meat.Consequently, they were applied in the formulation as starter cultures in an attempt toprepare a salami based on yeast fermentation. The incorporation of D. hansenii,individually, or in association with conventional starter cultures, resulted in a productwith improved taste and reduced maturation time.

[发布机构] University of the Free State