Contribution of several cheese-ripening microbial associations to aroma compound production

The aromatic potential of various cocultures of yeasts, Brevibacterium linens and lactic acid bacteria (LAB) was studied in cheese-based medium. Three yeasts (Debaryomyces hansenii, Geotrichum candidum and Kluyveromyces lochs) were cultivated in association with B. linens, in the presence or in the absence of LAB-added as the commercial lactic acid starter Flora Danica(R). Various parameters were analysed such as aroma compound production, the growth of each microorganism and lactose/lactate degradation. All tested yeasts could grow in all the associations regardless of the presence or the absence of LAB. LAB enhanced the growth of B. linens in D. hansenii associations, but they reduced B. linens' growth when associated with K. lactis. When cultivated alone. LAB produced very few aroma compounds and in lesser amount than the yeast-B. linens associations. In pure cultures of LAB, ethanol was the major volatile compound, and only scanty amounts of other volatile compounds were produced. The K. lactis-B. linens association exhibited the most diversified aroma compound profile with high quantities of S-methyl thioacetate and ethyl acetate. LAB promoted the synthesis of volatile sulphur compounds in this association.