In Vitro Characterisation of Potential Probiotic Bacteria Isolated from a Naturally Fermented Carrot and Ginger Brine

Unhealthy dietary patterns have been associated with an increase in mortality rate as well as the high occurrence of nontransmissible chronic degenerative diseases. Subsequently, the development of new functional foods has been proposed to reduce the incidence of nontransmissible chronic degenerative diseases. Probiotics represent a group of functional foods, defined as live microbial feeds, which provide the host with intestinal health benefits. The present study focused on the identification and characterisation of the probiotic potential of lactic acid bacteria isolated from a fermented carrot and ginger brine. Sixteen isolates were identified as Leuconostoc mesenteroides subsp. mesenteroides species, following preliminary screening based on 16S rDNA gene sequencing, and were further characterised for probiotic candidature. The probiotic properties tested included resistance towards gastrointestinal conditions (bile, acid, lysozyme tolerance), cell surface hydrophobicity, antioxidant activity, and antagonistic activity against intestinal pathogens. In general, all the isolated Leuconostoc mesenteroides subsp. mesenteroides strains exhibited high acid, bile, and lysozyme tolerance. They also showed strong antibacterial activity against common intestinal pathogens, i.e., Staphylococcus aureus and Escherichia coli, as well as antioxidant activity such as hydroxyl radical-scavenging ability and hydrogen peroxide resistance. Overall, Leuconostoc mesenteroides subsp. mesenteroides possesses a great potential as a beneficial strain for functional food.