Antibacterial activity of propolis-in-water emulsions in relation to polyphenol distribution. A case study on Listeria innocua
Abstract
Propolis, a bee-derived product rich in polyphenols such as flavonoids and phenolic acids, is known for its antibacterial activity. However, its low water solubility has limited its use mainly to hydroalcoholic extracts. In this study, propolis extracts (PE) were formulated as ethanol-free PE-in-water emulsions stabilized with gum Arabic. We investigated polyphenol distribution in emulsified PE and its antibacterial activity against Listeria innocua. HPLC analysis showed partial solubilization of phenolic acids in the aqueous phase, while both phenolic acids and flavonoids were present in the dispersed droplets. At a standardized total polyphenol concentration of 0.5 g gallic acid equivalents/L and an inoculum of ~5.0 × 10⁷ CFU/mL, emulsified propolis showed strong bactericidal activity across pH 5.5-6.8, whereas aqueous extracts mainly resulted in a slowing of bacterial growth. The antibacterial effect appears to depend on droplet-bacteria interactions, with the faster killing observed in the presence of both phenolic acids and flavonoids. Overall, emulsification promotes polyphenol partitioning while preserving antibacterial activity, supporting the potential use of ethanol-free propolis emulsions as antimicrobial ingredients for food applications.
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BibTeX
@article{hadjsassi2026antibacterial,
title = {{Antibacterial activity of propolis-in-water emulsions in relation to polyphenol distribution. A case study on Listeria innocua}},
author = {Abdessattar Hadj-Sassi and Julien Monteil and Isaura Caceres and Fernando Leal-Calderon},
journal = {Applied Food Research},
year = {2026},
month = oct,
doi = {10.1016/j.afres.2026.102649},
url = {https://hal.science/hal-05792764v1},
note = {CC BY-NC-ND 4.0},
}
RIS
TY - JOUR
TI - Antibacterial activity of propolis-in-water emulsions in relation to polyphenol distribution. A case study on Listeria innocua
AU - Abdessattar Hadj-Sassi
AU - Julien Monteil
AU - Isaura Caceres
AU - Fernando Leal-Calderon
PY - 2026
DA - 2026/10/11
JO - Applied Food Research
DO - 10.1016/j.afres.2026.102649
UR - https://hal.science/hal-05792764v1
AB - Propolis, a bee-derived product rich in polyphenols such as flavonoids and phenolic acids, is known for its antibacterial activity. However, its low water solubility has limited its use mainly to hydroalcoholic extracts. In this study, propolis extracts (PE) were formulated as ethanol-free PE-in-water emulsions stabilized with gum Arabic. We investigated polyphenol distribution in emulsified PE and its antibacterial activity against Listeria innocua. HPLC analysis showed partial solubilization of phenolic acids in the aqueous phase, while both phenolic acids and flavonoids were present in the dispersed droplets. At a standardized total polyphenol concentration of 0.5 g gallic acid equivalents/L and an inoculum of ~5.0 × 10⁷ CFU/mL, emulsified propolis showed strong bactericidal activity across pH 5.5-6.8, whereas aqueous extracts mainly resulted in a slowing of bacterial growth. The antibacterial effect appears to depend on droplet-bacteria interactions, with the faster killing observed in the presence of both phenolic acids and flavonoids. Overall, emulsification promotes polyphenol partitioning while preserving antibacterial activity, supporting the potential use of ethanol-free propolis emulsions as antimicrobial ingredients for food applications.
SN - 2772-5022
ER -