# Microencapsulation of Natural Food Antimicrobials: Methods and Applications
## 2 Encapsulation Methods  
In recent years, various encapsulation methods, antimicrobial agents and different wall materials have been extensively investigated. Their encapsulation efficiency (EE) and the main obtained results are summarized in Table 1. Encapsulation efficiency, release rate and biological properties of entrapped compounds were mostly investigated as important factors for evaluating the effectiveness of applied microencapsulation methods. EE is the percentage of molecules successfully encapsulated, i.e., the concentration of the molecule in the capsules over the initial concentration used to make the capsules. The release rate allows for determining if the molecules are released at the desired time and place. The antimicrobial properties will evaluate the capacity of the encapsulated molecules to inhibit or kill the target microorganism.  
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**Microencapsulation Method** & **Wall Material** & **Antimicrobial Agent** & **Encapsulation Efficiency** & **Main Results** & **References** \\ \hline Spray drying & Modified starch, & & & The inlet air temperature and the emulsion feed rate & \\  & gum arabic, & Oregona EO & - & significantly affected the powder recovery, moisture & [18] \\  & maltodextrin & & & content and the oil retention & \\ \hline Spray drying & Zein & Nisin & - & antimicrobials in inhibiting the growth of & [19] \\  & & & & _L monocytogenes_ & \\ \hline Simple coacervation & PVA & Lemongrass & & When SDS at 0.03 wt.\% was & \\  & crosslinked by & EO & - & used, no agglomeration & [20] \\  & glutaraldehydedehyde & & was observed & \\ \hline Simple coacervation & Gelatin & & & & Extended shelf-life of \\  & microparticles & Holy basil EO & 95.41\% & microencapsulated HBEO & [21] \\  & crosslinked with & (HBEO) & & up to 18 months at 25 \({}^{\circ}\)C & \\  & glutaraldehydedehyde & & & & \\ \hline Complex & Gelatin–gum & & & Genipin-hardened & \\  & arabic & Mustard seed & - & microcapsules exhibited & \\  & crosslinked & EO & - & strong chemical stability & \\  & with genipin & & & with a particle size of & \\  & & & & mainly 5–10 μm & \\ \hline Complex & Soy & & 72.01\% and 66.12\% & & This process preserves the & \\  & goxervation & Soy & for formulations & phenolic and flavonoids & \\  & protein–pectin & Propolis extract & with 2.5 and & compounds with & \\  & & & 5.0 g/100 mL of & & antioxidant activity and & \\  & & & & & inhibitory activity of \\  & & & & _S. aureus_ & \\ \hline Complex & Whey protein & & & & \\  & isolate–chitosan & Garlic extract & 51\% to 61\% & & The CH/WPI complexes are & \\  & & & & revealed to be good & \\  & isolate–chitosan & & & alternatives for use as & \\  & & & & wall systems & \\ \hline Single emulsion & Poly lactic acid & & & The encapsulation efficiency & \\  & diffusion method & (PLA) & Nisin & 12 to 16\% & \\  & & & & was enhanced with the & \\  & & & & increase in nisin loading in & \\  & & & & the aqueous solution & \\ \hline Emulsion diffusion & Polycaprolactone & & & 100\%, 90.9\% and & \\  & (PCL) & Eugenol & & \\  & & & 89.1\% for PCL, \(\beta\)-CD & & \\  & & & eugenol and & for eugenol encapsulation to & \\  & & & 2-HP-\(\beta\)-CD eugenol, & protect against light & \\  & & & & oxidation during & \\  & & & & storage time & \\ \hline s/o/w emulsion– & Poly & & & More hydrophilic polymers & \\ evaporation & (lactic-co-glycolic) & Lysozyme & 73\% & were less prone to & [27] \\ extraction & (PLGA) & & & protein adsorption & \\ \hline  & Calcium alginate– & & & The beads containing nisin & \\  & cellulose & & & significantly reduced the & \\  & nanocrystals & Nisin & - & _L. monocytogenes_ counts & \\  & & (CNC) & & after 28 days of storage & \\  & & & & compared with free nisin & \\ \hline \hline \end{tabular}
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Table 1: _Cont._