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Production of esters by Staphylococci
R Talon1, C Chastagnac, L Vergnais
1Station de Recherches sur la Viande, INRA Theix, Saint-Genès Champanelle, France.
International Journal of Food Microbiology
|January 30, 1999
Summary
Staphylococci strains can produce ethyl esters, important flavor compounds, from ethanol and short-chain fatty acids. This capability suggests their potential role in the flavor development during sausage manufacturing.
Area of Science:
- Food Microbiology
- Biochemistry
- Flavor Chemistry
Background:
- Staphylococci are common bacteria found in food production environments.
- Ethyl esters are key aroma compounds contributing to food flavors.
- Understanding microbial ester synthesis is crucial for controlling food quality.
Purpose of the Study:
- To investigate the capacity of Staphylococci, both resting cells and extracellular concentrates, to synthesize ethyl esters.
- To identify specific short-chain fatty acids and conditions favoring ester production by Staphylococci.
- To assess the potential of Staphylococci in contributing to ester formation during sausage manufacture.
Main Methods:
- Studying ester synthesis by resting Staphylococci cells and their extracellular concentrates.
- Incubating bacteria with ethanol and various individual short-chain fatty acids (acetic, butanoic, valeric, decanoic, and branched acids).
- Analyzing the influence of pH (5.5 and 7.0) and temperature (14°C and 24°C) on esterification activity.
Main Results:
- All tested Staphylococci strains synthesized ethyl esters.
- Staphylococcus warneri showed the highest ester production, while Staphylococcus carnosus had the lowest.
- Resting cells preferentially esterified butanoic acid, whereas extracellular concentrates esterified butanoic, valeric, and hexanoic acids.
- Acetic, decanoic, and branched acids were poorly esterified.
- Extracellular concentrate activity was optimal at pH 5.5-7.0 and 24°C, while resting cell activity was inhibited by acidic pH but unaffected by temperature.
- Staphylococci demonstrated ester production capabilities under conditions relevant to sausage processing.
Conclusions:
- Staphylococci possess a significant ability to synthesize various ethyl esters.
- The esterification activity varies between strains and depends on whether resting cells or extracellular concentrates are considered.
- Factors like substrate availability, pH, and temperature differentially affect ester synthesis by Staphylococci.
- The findings support the potential contribution of Staphylococci to flavor development in fermented sausages.