Characterization of yeasts isolated from artisanal short-ripened cows' cheeses produced in Galicia (NW Spain).

Characterization of yeasts isolated from artisanal short-ripened cows' cheeses produced in Galicia (NW Spain). Food Microbiol. 2016 Feb;53(Pt B):172-81 Authors: Atanassova MR, Fernández-Otero C, Rodríguez-Alonso P, Fernández-No IC, Garabal JI, Centeno JA Abstract A total of 143 presumptive yeast isolates were obtained from the predominant microflora of 21 short-ripened starter-free raw cow's milk cheeses made in Galicia (NW Spain), and the following 68 isolates were identified by both genotyping and sequencing methods: Yarrowia lipolytica (21 isolates), Kluyveromyces lactis (18), Debaryomyces hansenii (11), Pichia guilliermondii (11), Pichia fermentans (4) and Saccharomyces cerevisiae (3). Of these, Y. lipolytica and K. lactis displayed the strongest extracellular proteolytic activity on skim milk agar, and none of the D. hansenii isolates showed any activity on this medium. Y. lipolytica also displayed the highest lipolytic activity on Tween 80 and on tributyrin. This species, which was characterized by production of butanoic acid, free fatty acid esters and sulfur compounds in pasteurized whole milk, was responsible for rancid and cheesy flavors. K. lactis mainly produced acetaldehyde, ethanol, branched chain aldehydes and alcohols, and acetic acid esters, which were responsible for alcoholic, fruity and acetic notes. The volatile profiles of D. hansenii were rather limited and characterized by high levels of methyl ketone...
Source: Food Microbiology - Category: Food Science Authors: Tags: Food Microbiol Source Type: research