Abstract:In this paper, the bacteriostatic ability of tea saponin against three foodborn spoilage yeasts, Saccharomyces cerevisiae, Zygosaccharomyces routeri and Candida albicans, was evaluated by measuring the inhibitionzone, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Furthemore, the antibacterial mechanism was explored by using the time sterilization curve, biofilm inhibition rate, cell morphology, cell membrane permeability, cell membrane integrity, genetic material, protein leakage and total intracellular protein. The results of bacteriostatic ability test showed that tea saponin had bacteriostatic effect on three kinds of foodborne spoilage yeast. The inhibition zone of tea saponin on S. cerevisiae which had the most significant bacteriostatic effect was 16.00 mm, MIC and MBC were 0.05 mg/mL and 0.10 mg/mL respectively. The bacteriostatic mechanism of S. cerevisiae as indicator bacteria indicated that tea saponin could make the bacteria directly enter the depletion period, significantly inhibit the formation of biofilm and cause irreversible collapse and distortion of bacterial cells. Furthemore, it can not only destroy the integrity of cell membrane, increase the permeability of cell membrane, and leak a large number of intracellular nucleic acids and proteins, but also interfere with the normal synthesis of DNA and block the synthesis and expression of proteins. Therefore, tea saponin is expected to become a natural food preservative for foodborne spoilage yeast in food processing, and this study can also provide a theoretical basis for expanding the application of natural preservative in hypertonic food.
