[article]
| Titre : |
Enhancing antimicrobial efficacy of sodium benzoate |
| Type de document : |
texte imprimé |
| Auteurs : |
Stephen Foster, Auteur ; Pawel Rempala, Auteur ; Daniel Mueller, Auteur ; Lauren Dornan, Auteur ; Amber Yarnell, Auteur ; Jenna Blankenship, Auteur |
| Année de publication : |
2020 |
| Article en page(s) : |
p. 8-14 |
| Note générale : |
Bibliogr. |
| Langues : |
Anglais (eng) |
| Catégories : |
Antimicrobiens
Benzoate de sodiumLe benzoate de sodium, de formule chimique (Na+ + C6H5COO-)(NaC6H5COO) est le sel de sodium de l'acide benzoïque, connu sous le nom E211 comme additif alimentaire. Soluble à raison de 640 parts pour 1000 d'eau à 25 °C. Il précipite en présence d'un acide concentré (ex.: l'acide sulfurique concentré) en donnant de l'acide benzoïque (très peu soluble dans l'eau) dont on peut analyser plus facilement le point de fusion. Sa dissolution aqueuse engendre une augmentation du pH.
L'acide benzoïque est produit industriellement selon 3 voies :
1. Oxydation de naphtalène en anhydride phtalique en présence de catalyseur oxyde de vanadium. L'anhydride phtalique est ensuite décarboxylé produisant l'acide benzoïque.
2. Oxydation d'un mélange de toluène et d'acide nitrique produisant l'acide benzoïque.
3. Hydrolyse du trichlorobenzène produisant l'acide benzoïque.
L'acide benzoïque est ensuite dissout dans une solution d'hydroxyde de sodium pour former du benzoate de sodium.
Le benzoate de sodium est utilisé comme conservateur alimentaire, autorisé sous condition et référencé en Europe sous le code E211.
Détergents
Produits nettoyants
|
| Index. décimale : |
668.1 Agents tensioactifs : savons, détergents |
| Résumé : |
In many cleaning product applications in the market place, the inclusion of sodium benzoate as a stand-alone preservative is providing sufficient microbial control. It was observed that inclusion levels are typically lower, resulting in economical use and, consequently, feasibility in a wider pH range of cleaning products compared to what was generally believed. For sodium benzoate
to effectively preserve, formulations require sufficient concentrations of the undissociated organic acid, which is benzoic acid. The acid equilibrium constant (pKa) of benzoic acid determines the degree of acid dissociation, and a larger value would result in increased benzoic acid concentrations. Titrations show that in the presence of home care surfactants, the apparent pK’a increases as surfactant concentration increases, indicating a higher concentration of the active substance. This was confirmed with 13CNMR. Microbial challenge testing was performed to verify that the increased apparent pK’a yields increased antimicrobial efficacy. A surfactant was selected to increase the benzoic apparent pK’a with substantial improvements in microbe reductions versus controls. Finally, a theoretical model based on surfactant properties was adopted to explain the observed pK’a increases. This model provides a basis for detailed formulation advice and justification to the enhanced antimicrobial efficacy of Kalaguard® SB sodium benzoate. |
| Note de contenu : |
- BACKGROUND : Mechanisms for antimicrobial action and pK' a shifts
- EXPERIMENTAL :
- RESULTS AND DISCUSSION : Observing increased antimicrobial efficacy - Measuring pK'a with 13CNMR - Modelling apparent pK'a values based on micelle partitioning
- Fig. 1 : Microbial counts in colony forming units (CFU) for Escherichia coli, Pseudomonas aeruginosa, and Aspergillus brasiliensis of hand diswash formulation pH 6.0.
- Fig. 2 : The apparent pK'a of benzoic acid increased with the concentration of various surfactants
- Fig. 3 : 13CNRM chemical shift of the carbon atom within the carboxyl functional group of sodium benzoate/benzoic acid at various pH levels
- Fig. 4 : Fraction of undissociated benzoic acid calculated from 13CNMR chemical shift data at various pH
- Fig. 5 : Depiction of the equilibrium between base and acid dissolved in water and acid incorporated into the micelle core
- Fig. 6 : Graph of apparent pK'a versus LAS concentration from experimentally measured and theoretically derived values from equation 2
- Table 1 : Log reduction of microbes in soy broth at pH 6.5 at 14 days, demonstrating that sodium benzoate combined with SLMI surfactant resulted in greater antimicrobial efficacy
- Table 2 : pK'a interpolated from benzoic acid 0.5 molar fraction using 13CNMR data in Fig. 4
- Equation 1 : Determination of benzoic acid dissociation (ionization) degree α from the carboxyl carbon chemical shift
- Equation 2 : Apparent pK'a of benzoic acid withsurfactants. For full derivation on details, please contact author |
| En ligne : |
https://drive.google.com/file/d/1_JnUEMJ69pY7SlWH5_83hX1UNS7aGWNQ/view?usp=drive [...] |
| Format de la ressource électronique : |
Pdf |
| Permalink : |
https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=34594 |
in SOFW JOURNAL > Vol. 146, N° 10 (10/2020) . - p. 8-14
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