Genotypic identification and technological characterization of lactic acid bacteria isolated from traditional Turkish Kargi tulum cheese
Kargi tulum cheese is an artisanal cheese produced through the spontaneous fermentation of raw milk ripened inside a goat-skin bag. The objective of this study was to characterize the dominant species of natural lactic acid bacteria (LAB) found in Kargi tulum cheese. Some technologically important properties of LAB isolates were also determined. Seven samples of cheese of different levels of ripeness were taken from local producers and 97 isolates were obtained from these samples. Non-spore forming, Gram-positive, catalase- and oxidase-negative isolates were assessed as LAB. Based on genotypic characterization, the dominant LAB were identified as Lactobacillus paracasei (43.3%), Lactobacillus plantarum (23.7%), Enterococcus durans (6.2%), Streptococcus thermophilus (6.2%), Lactobacillus brevis (5.2%), Enterococcus faecium (5.2%), Lactobacillus fermentum (4.1%) and Lactobacillus pentosus (1%). Homofermentative strains such as L. paracasei, L. plantarum, S. thermophilus; E. durans and E. faecium were selected as probable starter cultures. These strains were tolerant to 6.5% salt. They are also characterized by acidification ability (from pH = 6.6 to 4.7 to 6.0, in 6 to 8 h), low proteinase and high peptidase, esterase, esterase-lipase, β-galactosidase and β- glucosidase activities. They also produce diacetyl and H2O2.
Key words: Lactic acid bacteria, genotypic characterization, technological characterization, tulum cheese.