Influence of gallic acid and catechin polyphenols on probiotic properties of Streptococcus thermophilus CHCC 3534 strain
2010
Khalil, Rowaida K. S
The study aimed at assessing the potential influences of two polyphenolic compounds on growth and some recently proven probiotic attributes of Streptococcus thermophilus CHCC 3534. The strain was tolerant to 0.8% gallic acid and 0.3% catechin. Gallic acid and catechin adapted cells were moderately to highly sensitive to most antibiotics, and to low pH (2.0) compared to the parental cells. Gallic acid adapted cells survived pHs 3.0 and 4.0, and were rapid β-galactosidase producers. Catechin adapted cells demonstrated marked tolerance to 0.4% oxgall, and possessed low hydrophobicity to organic solvents tested. They also produced large capsules of 5.0 μm in diameter due to high content of glucose and galactose monomers as determined by gas chromatography mass spectroscopy. Matrix-assisted laser-desorption time-of-flight mass spectrometry analysis detected small peptide subunits of masses 656 Da in bacteriocins of adapted cells that significantly inhibited the growth of Escherichia coli O157:H7, Pseudomonas aeroginosa, and Listeria monocytogenes. The data demonstrates that selection of S.thermophilus 3534 strain in dairy products and formulations supplemented with polyphenolics may present a nutritional benefit as a promising probiotic starter candidate as well as a potential source of dietary antioxidants.
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