Abstract
Species belonging to the Zygosaccharomyces bailii sensu lato clade are some of the most troublesome spoilage yeasts of acidic food products, primarily due to their resistance towards synthetic food preservatives, like weak organic acids. Therefore alternative, powerful and more natural antifungal agents are needed. Herein, prenylated isoflavonoids, present mainly in the Leguminosae family, were investigated for their antifungal properties (including potency and mode of action) against a Z. bailii food isolate, its interspecies hybrid, Z. parabailii. The mono-prenylated isoflavonoids, wighteone and glabridin were the most active, with minimum fungicidal concentrations (MFC) of 12.5 μg/mL (37 μM) and 25 μg/mL (77 μM), respectively, at pH 4.0, rendering them over 20 times (on weight basis) more potent than sorbic acid (MFC 550 μg/mL, 4.5 mM). The two active mono-prenylated isoflavonoids induced killing within 15 min, suggesting potential membrane activity. Membrane permeabilization by these molecules was confirmed by propidium iodide uptake and TEM imaging. Membrane permeabilization was accompanied with leakage of intracellular material. Molecular properties such as the electrostatic energy potential and the hydrophobic integy moment were correlated to activity through a binary classification quantitative structure-activity relationship (QSAR) model. Altogether, mono-prenylated isoflavonoids can serve as highly potent, novel and natural antifungal against Z. parabailii acting by severely compromising the membrane integrity.
Highlights
Spoilage yeasts constitute one of the most important challenges in food and drink preservation
Eight mono-prenylated isoflavonoids had a minimum inhibitory concentrations (MICs) value ≤ 25 μg/mL, which is associated with a good antimicrobial activity (Gibbons, 2004) (Table 1)
Given that prenylated isoflavonoids are thought to act in a different fashion to sorbic acid (Araya- Cloutier et al, 2018b; Stratford et al, 2013a, 2020), we explored the synergistic potential of their mixture
Summary
Spoilage yeasts constitute one of the most important challenges in food and drink preservation. Z. bailii is strongly associated with spoilage of foods with a high sugar content and/or acidic foods e.g. fruit juices and sauces (pH 3.0–4.0) (Beuchat, 1982; Stumbo, 1973), and it is known for its resistance towards cleaning agents and disinfectants (high concentration of ethanol (>15% v/v)) (Davenport, 1996), impeding the cleaning of food-processing equipment (Deak et al, 1994; Fleet, 1992) Weak organic acids such as sorbic, acetic and lactic acid are typically used to control the growth of Z. bailii (Beuchat, 1982; Martorell et al, 2007). High concentrations of sorbic acid are associated with strong and undesirable fatty acid odor (Fujita et al, 2008)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
