Controlled Release Mechanism and Antibacterial Effect of Layer‐By‐Layer Self‐Assembly Thyme Oil Microcapsule

Abstract

Thyme essential oil‐loaded microcapsules (TMS) were fabricated using natural polysaccharide chitosan (CS) and sodium alginate (SA) as the shell material via the method of layer‐by‐layer (LBL) assembly. The accumulated release rates of thyme oil and microcapsules at 4 °C were 42.50% and 10.16%, respectively. After heating at 100 °C for 5 hr, the release rate of the 0, 2, 4, 6 layers assembled microcapsules were 100%, 48.84%, 28.38%, 19.3%, severally. Microcapsules also had good pH sensitivity in the range of 4 to 10. Antimicrobial function studies showed that the microcapsules are more effective than thyme oil for three tested microorganisms. When the temperature rose from 37 °C to 121 °C, the antibacterial zone of thyme oil gradually decreased from 18.5 ± 0.6 mm to 12.3 ± 0.6 mm, although inhibition rate of microcapsules increased from 87.97% to 99.75%. The antibacterial effect of thyme oil declined with the increase of pH, in terms of microcapsules, the efficiency was better under acidic or alkaline conditions. The thyme oil microcapsules can suppress the growth of Staphylococcus aureus in milk and prolong its shelf life. It was determined that this microcapsule could be a potential alternative as a natural antimicrobial agent in food and pharmaceutical industries. Practical Application This work provided release performance and mechanism of layer‐by‐layer (LBL) thyme oil microcapsule under different conditions, and further studies showed its antibacterial ability to explore how herb essential oils can be potentially applied in food packaging and antibacterial areas.

Chemical Composition and Bioactivity of Essential Oil of Ten Labiatae Species

“…Nevertheless, McEO, OvEO and TmEO had obvious antibacterial effect on S. aureus, with the MIC value were 1, 2, 2 μL/mL respectively, is consistent with the IZD results. The MIC value for TmEO to B. subtilis , S. aureus and E. coli is higher than the results of Zhang et al [ 31 ], while nearly the same with the results of Niu et al [ 33 ]. The differences of thyme phenol content which was the main ingredient in TmEO maybe the main reason.…”

“…They also showed strong inhibitory effects on Escherichia coli (E. coli) , Bacillus subtilis (B. subtilis), and Salmonella enteritidis (S. enteritidis) . TmEO presented better antibacterial effect on S. aureus , compared with the results from Zhang et al [ 31 ], in which the IZD value was 19.1 mm, although worse on B. subtilis and E. coli, with the IZD value of 34.5 and 15.0 mm respectively. The results of McEO is better than Li et al [ 19 ], which the IZD value was 14.7 mm ( S. aureus ) and 8.0 mm ( E. coli ).…”

“…The temperature only obviously affects TmEO, McEO and OvEO, with no significant fluctuations on the rest seven EOs. Though the results shown that the EOs own thermal stability, lots of reported work have directly choose 37 °C as experimental temperature [ 19 , 31 , 32 , 33 ].…”

Development of Bio-Active Patches Based on Pectin for the Treatment of Ulcers and Wounds Using 3D-Bioprinting Technology

“…A medium pouring method was used to determine the antimicrobial activity of the 3D-printed patches containing CCP against two bacterial strains (Staphylococcus aureus and Escherichia coli) [23]. Three-dimensional-printed patches (discs with diameter 1 cm, height 0.15 mm and weight 40 mg) were sterilized by UV light (30 W, 1.0 m) for 30 min.…”

Preparation and characterization of β‐cyclodextrin–oregano essential oil microcapsule and its effect on storage behavior of purple yam

“…20 Zhang et al used the natural polysaccharides CS and SA as shell materials to prepare thyme essential oil microcapsules using a layer-by-layer assembly method, which successfully improved the antibacterial effect of the essential oil. 21 Therefore, in this present study, we have focused on the fabrication of edible microcapsules using oregano essential oil and cyclodextrin. Encapsulation efficiency, antibacterial efficacy, Fourier infrared spectra, and thermal and particle morphology of the edible microcapsules were assessed.…”