UDC 579.6; 615.326
doi: 10.36871/vet.san.hyg.ecol.202401011
Authors
Elena V. Sorokina,
Saria D. Dbar,
Lidiya G. Stoyanova,
Lomonosov Moscow State University, Moscow 119234, Russian Federation
Abstract
Research has been conducted to develop an effective method for preserving the probiotic properties of Lactococcus lactis ssp. lactis strain 194, isolated from milk in Buryatia (Russia). The effect of 10 protective media added before freezing was compared: NaCl, skim milk, 5% sucrose+1% gelatin and smectite at concentrations of 5, 10 and 5% as a cryoprotectant. Physiological and probiotic properties: survival rate, rate of milk clot formation, lactic acid formation and antimicrobial activity were studied in lyophilized bacteria immediately after reconstitution, as well as in a number of passages after long-term storage. Optimal concentrations of smectite were selected using a toxicological method, and particle sizes and the morphology of the surface of lactococcal cells in the presence of a cryoprotector were determined using electron microscopy. It was found that the most effective method of preserving the probiotic properties of lactic acid bacteria is lyophilization with the addition of V% smectite, which ensured high cell survival in the first passage and preserved the number of bacteria and their probiotic potential after long-term storage.
Keywords
Lactococcus lactis ssp. lactis, antimicrobial activity, cryoprotectants, lyophilization, smectite, storage
