Weak-acid preservatives: pH and proton movements in the yeast Saccharomyces cerevisiae

Stratford, Malcolm; Nebe-von-Caron, Gerhard; Steels, Hazel; Novodvorska, Michaela; Ueckert, J.; Archer, David B.

doi:10.1016/j.ijfoodmicro.2012.12.013

Cited by 82 publications

(60 citation statements)

References 43 publications

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“…Two strains of S. cerevisiae were also included as reference strains. Previous research had shown these strains to be typical representatives of S. cerevisiae with respect to weak-acids (Stratford et al, 2013). Tests were carried out on the resistance of strains to sorbic, benzoic and acetic acids in YEPD at pH 4.0 (Table 1).…”

Section: Resultsmentioning

confidence: 99%

Extreme resistance to weak-acid preservatives in the spoilage yeast Zygosaccharomyces bailii

Stratford

Steels

Nebe-von-Caron

et al. 2013

International Journal of Food Microbiology

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130

119

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Weak-acid preservatives, such as sorbic acid and acetic acid, are used in many low pH foods to prevent spoilage by fungi. The spoilage yeast Zygosaccharomyces bailii is notorious for its extreme resistance to preservatives and ability to grow in excess of legally-permitted concentrations of preservatives. Extreme resistance was confirmed in 38 strains of Z. bailii to several weak-acid preservatives. Using the brewing yeast Saccharomyces cerevisiae as a control, tests showed that Z. bailii was ~ 3-fold more resistant to a variety of weak-acids but was not more resistant to alcohols, aldehydes, esters, ethers, ketones, or hydrophilic chelating acids. The weak acids were chemically very diverse in structure, making it improbable that the universal resistance was caused by degradation or metabolism. Examination of Z. bailii cell populations showed that extreme resistance to sorbic acid, benzoic acid and acetic acid was limited to a few cells within the population, numbers decreasing with concentration of weak acid to < 1 in 1000. Re-inoculation of resistant sub-populations into weak-acid-containing media showed that all cells now possessed extreme resistance. Resistant sub-populations grown in any weak-acid preservative also showed ~ 100% cross-resistance to other weak-acid preservatives. Tests using 14C-acetic acid showed that weak-acid accumulation was much lower in the resistant sub-populations. Acid accumulation is caused by acid dissociation in the higher pH of the cytoplasm. Tests on intracellular pH (pHi) in the resistant sub-population showed that the pH was much lower, ~ pH 5.6, than in the sensitive bulk population. The hypothesis is proposed that extreme resistance to weak-acid preservatives in Z. bailii is due to population heterogeneity, with a small proportion of cells having a lower intracellular pH. This reduces the level of accumulation of any weak acid in the cytoplasm, thus conferring resistance to all weak acids, but not to other inhibitors.

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Section: Resultsmentioning

confidence: 99%

Extreme resistance to weak-acid preservatives in the spoilage yeast Zygosaccharomyces bailii

Stratford

Steels

Nebe-von-Caron

et al. 2013

International Journal of Food Microbiology

Self Cite

130

119

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“…Thus, to maintain intracellular homeostasis the yeast cell requires mechanisms that can reduce the concentration of protons in the cytoplasm. It has been reported that S. cerevisiae can decrease extracellular pH during the first hours of cell growth (lag phase) when exposed to weak acids such as cinnamic acid (Chambel et al 1999) and sorbic and acetic acids (Stratford et al, 2013). These results suggest that the proton pump Pma1p is stimulated when S. cerevisiae is cultured in the presence of weak acids.…”

Section: Evaluation Of Extracellular Acidification During Yeast Growthmentioning

confidence: 86%

The effect of hydroxycinnamic acids on growth and H+-ATPase activity of the wine spoilage yeast, Dekkera bruxellensis

Godoy¹,

Varela²,

Martı́nez³

et al. 2013

Afr. J. Microbiol. Res.

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Hydroxycinnamic acids are lipophilic compounds naturally present in grape must, and proposed to have antimicrobial properties. Consequently, microorganisms that grow in media containing these acids must have efficient adaptation mechanisms. In Saccharomyces cerevisiae hydroxycinnamic acids enter into the cell where they are deprotonated causing a decrease in internal pH, this variation in the intracellular pH is counteracted by an increase in the activity of the H + -ATPase pump Pma1p. Dekkera bruxellensis however, is able to transform hydroxycinnamic acids into volatile-less toxic derivates, a mechanism used by few yeast species. Nonetheless, D. bruxellensis could also have an adaptation mechanism similar to that of S. cerevisiae. Our results showed that hydroxycinnamic acids caused a longer lag phase during D. bruxellensis growth, particularly when supplementing media with ferulic acid. Additionally, extracellular pH decreased while Pma1p activity increased during lag phase in media supplemented with p-coumaric acid. These results suggest the existence of a complementary mechanism of resistance to hydroxycinammic acids in D. bruxellensis which involves the H + -ATPase pump Pma1p.

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“…Moreover, prolonged usage of these preservatives against spoilage fungi may lead to the development of fungal resistance to them [26,27].…”

Section: Chemical Treatmentsmentioning

confidence: 99%

Strategies to Extend Bread and GF Bread Shelf-Life: From Sourdough to Antimicrobial Active Packaging and Nanotechnology

Melini¹,

Melini²

2018

Fermentation

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Bread is a staple food worldwide. It commonly undergoes physico-chemical and microbiological changes which impair its quality and shelf-life. Staling determines organoleptic impairment, whereas microbiological spoilage causes visible mould growth and invisible production of mycotoxins. To tackle this economic and safety issue, the bakery industry has been working to identify treatments which allow bread safety and extended shelf-life. Physical methods and chemical preservatives have long been used. However, new frontiers have been recently explored. Sourdough turned out an ancient but novel technology to preserve standard and gluten-free bread. Promising results have also been obtained by application of alternative bio-preservation techniques, including antifungal peptides and plant extracts. Active packaging, with absorbing and/or releasing compounds effective against bread staling and/or with antimicrobials preventing growth of undesirable microorganisms, showed up an emerging area of food technology which can confer many preservation benefits. Nanotechnologies are also opening up a whole universe of new possibilities for the food industry and the consumers. This work thus aims to provide an overview of opportunities and challenges that traditional and innovative anti-staling and anti-spoilage methods can offer to extend bread shelf-life and to provide a basis for driving further research on nanotechnology applications into the bakery industry.

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Weak-acid preservatives: pH and proton movements in the yeast Saccharomyces cerevisiae

Cited by 82 publications

References 43 publications

Extreme resistance to weak-acid preservatives in the spoilage yeast Zygosaccharomyces bailii

Extreme resistance to weak-acid preservatives in the spoilage yeast Zygosaccharomyces bailii

The effect of hydroxycinnamic acids on growth and H+-ATPase activity of the wine spoilage yeast, Dekkera bruxellensis

Strategies to Extend Bread and GF Bread Shelf-Life: From Sourdough to Antimicrobial Active Packaging and Nanotechnology

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