Probiotic and Antioxidative Properties of L. Lactis LL27 Isolated from Milk

ABSTRACT

The aim of this study was to determine the probiotic properties of Lactococcus lactis subsp. lactis LL27, namely its resistance to bile salt, pepsin, pancreatin, acid and antibiotics. Moreover, the ability of L. lactis to inhibit the adhesion of Escherichia coli ETEC and Salmonella Typhimurium SL1344 to Caco-2 cells were examined and also the hydrophobicity, iron-ion chelating ability, and determination of α, α-diphenyl-β-picrylhydrazyl (DPPH) radical-scavenging ability of the organism were investigated. L. lactis LL27, nisin A producer, was able to inhibit the growth of Gram-positive bacteria including spoilage and pathogenic strains. L. lactis LL27 exhibited high levels of resistance to low pH, bile salts, pepsin and pancreatin, which are conditions characteristic of the gastrointestinal tract environment. LL27 was found to adhere to Caco-2 and CCL-221 cell lines at a rate of 13 ± 2.3% and 29 ± 2.6%, respectively. In addition its presence reduced the ability of pathogenic bacterial species Escherichia coli ETEC and Salmonella Typhimurium SL 1344 to adhere to Caco-2 cells. The hydrophobicity, DPPH radical-scavenging activity and iron ion-chelating ability of the tested LL27 were found to be 83.48 ± 1.45%, 75 ± 3% and 29.5 ± 3%, respectively. Scanning electron microscopy revealed the LL27 to be located inside Caco-2 and CCL-221 mammalian cells. These findings suggested that L. lactis LL27 has good probiotic properties and could be used in functional foods.

Keywords:

• Lactocococcus lactis
• probiotic
• Caco-2
• adhesion
• hydrophobicity
• DPPH radical