Enterococcus faecium strain used as an adjunct culture in a starter for kashkaval cheese plays important role to proteolytic processes and release of bioactive peptides during ripening

Correspondence: Zhechko Dimitrov LB-Bulgaricum Plc. R&D Center, Sofia, Bulgaria e-mail: [email protected] ABSTRACT In the present study the potential of preliminary selected strain Enterococcus faecium used as an adjunct culture in starter for kashkaval cheese was evaluated. The strain Enterococcus faecium MH3 was selected among 17 isolates on the basis of its high level of proteolytic and peptidase activities. The active proteolytic system of E. faecium MH3 leads to high level of transformation of caseins to end products. A high degree of transformation of β-casein and αs1casein in the initial stage of ripening (up to 15 d) and during storage up to 90 d was determined by Urea-Polyacrylamide gel electrophoresis (exceptionally high degree of degradation – 91% and 83% for αs1-casein and β-casein). The results reveal that the new starter combination, including strain Enterococcus faecium MH3 as a nonstarter culture, can be successfully used to enhance proteolysis, shorten the ripening period and improve the quality of hard cheeses. Kashkaval produced using Enterococcus faecium MH3 in the starter contains significantly more free amino acids and increased concentration of low molecular weight peptides. The inhibitory activity of low molecular weight peptides against angiotensin-converting enzyme was significantly higher than those of common kashkaval cheese. The aim of the present work was to study the possible use of Enterococcus faecium strain as an approach towards enhancing the proteolytic processes during Kashkaval cheese ripening, acceleration of the ripening process and improving the quality of the end product.