# Nanoencapsulation of Essential Oils as Natural Food Antimicrobial Agents: An Overview
## 6 Effect of Nanoencapsulation on the Antimicrobial Activity of Essential Oils
Studies have found that different sizes of limonene and cinnamic acid nanoemulsions have no significant difference in the inhibitory effect on spoilage yeast or _Escherichia coli_, which was closely related to the composition of the emulsion system [12]. In addition, compared to a conventional emulsion, nanoencapsulated lipophilic antimicrobial agents are generally believed to penetrate more easily through the microbial membrane, resulting in an improved bactericidal activity. This is because the dispersion of the lipophilic antimicrobial agent in the nanoemulsion will result in an increase of the interactions with the binding sites on the targeting bacteria. It can be assumed that antimicrobial agents may more fully contact the cells and promote efficient release of the active substance in the cell, thereby providing an opportunity to increase its bioavailability and consequently enhancing the bacteriostatic effect. However, there have been results reported by [PERSON] [133] and [PERSON] et al. [140] which showed that the antibacterial activity of encapsulated EOs was not affected by the droplet size. These clearly controversial results suggest that a decrease in droplet size does not necessarily mean the enhancement of the function of the essential oil nanoemulsions. \begin{table}
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**Delivery System** & **Biactive Compounds** & **Encapsulating Material** & **Techniques** & **Size** & **Major Findings** & **References** \\ \hline \multirow{4}{*}{Nanemulsion (prepared low-energy methods)} & \multirow{2}{*}{Thymol} & Zein-Sodium caseinate & Emulsion polymerization & \multirow{2}{*}{65.8–87.6 nm} & \multirow{2}{*}{ \begin{tabular}{} \end{tabular}  } & Compared with the control, the encapsulated thymol was more effective in lowering _S. aureus_ counts during a period of 13 days & [141] \\  & & & & & High encapsulation efficiency close to 100\%; the antioxidant and antimicrobial activity of nanemulsions was improved & [57] \\  & & & & & & \\ \cline{1  
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**Delivery System** & **Biactive Compounds** & **Encapsulating Material** & **Techniques** & **Size** & **Major Findings** & **References** \\ \hline \hline \multirow{9}{*}{Nanoemulsion (prepared by high-energy participants, participants, rose or snowe or snowe or snowe or snowe)} & \multirow{3}{*}{Prepermit oil} & Medium-chain triacylglycerollycerol & High pressure homogenization & \textless{}200 nm & Nanoemulsions containing EO showed improved antimicrobial activity against _Listerium macrophages_ and _Staphylococcus aureus_ & [112] \\ \cline{2-6}  & Eucalyptus oil & Tween 80 & Ultrasonication & 17.1 nm & Nanomiculous containing eucalyptus showed to inactivate EO _creates_ at 0 min, _S. aureus_ at 15 min, and _E. coli_ at 1 h & [142] \\ \cline{2-6}  & Essential oils (Lemongrass, elbowe, tea, tree, rhyme, paramaras, roeswood, or arm) & & & & \\ \cline{2-6}  & Essential oils (Lemongrass, droes, tea, tree, rhyme, paramaras, roeswood, sage or arm) & & & & \\ \cline{2-6}  & _Thymus_ & Soybean oil and SDS (sodium dodecylsulfate) & High pressure micro-fluidizer & \textless{}10 nm & Nanoencapsulated EO exhibited higher antibacterial inhibition diameters against _Staphylococcus aureus_ compared to those formed by free EO & [143] \\ \hline \multirow{9}{*}{SLNs} & \multirow{3}{*}{Nisin} & Cotylanimate, Sofian 378, Sofian 154, Invitrogen 900 and Witepol ES5 & High pressure homogenization & \textless{}19 nm & The antibacterial activity of resin-loaded SLNs against _L. microorganisms_ and _L. Entertainment_ was up to 20 and 15 days, respectively, while the free resin was only 1 day and 3 days, respectively. & [144] \\ \cline{2-6}  & _Zataria multiflows oil_ & Glycerol monostearat and Precid? & High-shear homogenization and ultrasound & 255.5 nm & _Z.