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David Julian Mcclements - One of the best experts on this subject based on the ideXlab platform.

  • Development of antibacterial nanoemulsions incorporating Thyme Oil: Layer-by-layer self-assembly of whey protein isolate and chitosan hydrochloride.
    Food chemistry, 2020
    Co-Authors: Jialin Sun, David Julian Mcclements, Jun Yan, Sairui Zhang, Chao Shi, Xuebo Liu, Fuguo Liu
    Abstract:

    Abstract The aim of this study was to develop a Thyme Oil emulsion with good physicochemical properties and antibacterial activity. Initially, Oil-in-water emulsions containing whey protein-coated essential Oil droplets were prepared by high-pressure homogenization. The double-layer emulsions were formed around the Oil droplets by electrostatic deposition of cationic chitosan hydrochloride onto the anionic protein-coated droplets. Then, the structure, physicochemical properties, and storage stability of the emulsions were determined. Emulsions formulated using 1% v/v Thyme Oil, 0.7 wt% whey protein, and 0.25 wt% of chitosan hydrochloride contained relatively small cationic droplets. Moreover, the emulsions containing double-layer coatings were shear-thinning fluids. Storage tests indicated that double-layer emulsions had better stability than the single-layer. Antibacterial tests indicated that the double-layer emulsions exhibited prolonged antibacterial activity against two model food pathogens: E. coli and S. aureus. These results provide a scientific basis for the rational design of antimicrobial delivery systems for use in foods.

  • Effect of ripening inhibitor type on formation, stability, and antimicrobial activity of Thyme Oil nanoemulsion.
    Food chemistry, 2017
    Co-Authors: Victor Ryu, David Julian Mcclements, Maria G. Corradini, Lynne Mclandsborough
    Abstract:

    Abstract The objective of this research was to study the impact of ripening inhibitor level and type on the formation, stability, and activity of antimicrobial Thyme Oil nanoemulsions formed by spontaneous emulsification. Oil-in-water antimicrobial nanoemulsions (10 wt%) were formed by titrating a mixture of essential Oil, ripening inhibitor, and surfactant (Tween 80) into 5 mM sodium citrate buffer (pH 3.5). Stable nanoemulsions containing small droplets ( d  canola > coconut which also depended on their ability to transfer hydrophobic antimicrobial constituents to the separated hydrophobic domain.

  • improvements in the formation and stability of fish Oil in water nanoemulsions using carrier Oils mct Thyme Oil lemon Oil
    Journal of Food Engineering, 2017
    Co-Authors: Rebecca M Walker, Eric A Decker, Cansu Ekin Gumus, David Julian Mcclements
    Abstract:

    Abstract Nanoemulsion-based delivery systems are particularly effective tools for incorporating omega-3 polyunsaturated lipids into many foods and beverages. In this study, the impact of carrier Oil type and concentration on the formation and stability of fish Oil-in-water nanoemulsions was determined. Three carrier Oils with different physicochemical and sensory properties were evaluated: medium chain triglycerides (MCT); lemon Oil; and Thyme Oil. Nanoemulsions (d   Thyme Oil. This effect was attributed to the presence of high levels of natural antioxidants (phenolics) within the lemon and Thyme Oils. These results show that selection of an appropriate carrier Oil type and concentration can lead to the formation of fish Oil nanoemulsions with good physical and chemical stability.

  • fabrication stability and efficacy of dual component antimicrobial nanoemulsions essential Oil Thyme Oil and cationic surfactant lauric arginate
    Food Chemistry, 2015
    Co-Authors: Yuhua Chang, David Julian Mcclements, Lynne Mclandsborough
    Abstract:

    The influence of a cationic surfactant (lauric arginate, LAE) on the physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions was investigated. Nanoemulsions prepared from pure Thyme Oil were highly unstable due to Ostwald ripening, but they could be stabilized by adding a ripening inhibitor (corn Oil) to the Oil phase prior to homogenisation. The loading capacity and antimicrobial efficacy of Thyme Oil nanoemulsions were significantly increased by adding LAE. In the absence of LAE, at least 60 wt% corn Oil had to be added to the lipid phase to inhibit Ostwald ripening; but in the presence of 0.1 wt% LAE, only 30 wt% corn Oil was needed. LAE addition substantially increased the antimicrobial efficacy of the Thyme Oil nanoemulsions: 200 μg/ml Thyme Oil was needed to inhibit growth of a spOilage yeast (Zygosaccharomyces bailii) if LAE was added, whereas ⩾ 400 μg/ml was needed in the absence of LAE.

  • physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions influence of ripening inhibitors
    Journal of Agricultural and Food Chemistry, 2012
    Co-Authors: Yuhua Chang, Lynne Mclandsborough, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions (pH 3.5) were prepared as potential antimicrobial delivery systems. The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of Thyme Oil. Ostwald ripening could be inhibited by mixing Thyme Oil with a water-insoluble ripening inhibitor (≥60 wt % corn Oil or ≥50 wt % MCT in the lipid phase) before homogenization, yielding nanoemulsions with good physical stability. Physically stable Thyme Oil nanoemulsions were examined for their antimicrobial activities against an acid-resistant spOilage yeast, Zygosaccharomyces bailii (ZB). Oil phase composition (ripening inhibitor type and concentration) had an appreciable influence on the antimicrobial activity of the Thyme Oil nanoemulsions. In general, increasing the ripening inhibitor levels in the lipid phase reduced the antimicrobial efficacy of nanoemulsions. For example, for nanoemulsions containing 60 wt % corn Oil in the ...

Qixin Zhong - One of the best experts on this subject based on the ideXlab platform.

  • Physical and antimicrobial properties of neutral nanoemulsions self-assembled from alkaline Thyme Oil and sodium caseinate mixtures.
    International journal of biological macromolecules, 2020
    Co-Authors: Yue Zhang, Qixin Zhong
    Abstract:

    Abstract The objective of this study was to utilize self-assembly properties of sodium caseinate to prepare nanoemulsions after neutralization of alkaline mixtures with 2% w/v caseinate and up to 3% v/v Thyme Oil. The encapsulation efficiency was >90% at a surfactant-to-Oil ratio of up to 1:1.25. The nanoemulsions had structures smaller than 75 nm according to atomic force microscopy and stable hydrodynamic diameters of ~90–200 nm during 20-day storage at room temperature. When tested against Escherichia coli O157:H7 ATCC 43895 and Staphylococcus aureus ATCC 25923 in tryptic soy broth and milk, the encapsulated Thyme Oil was more active than free Thyme Oil. Additionally, S. aureus was more resistant than E. coli O157:H7, requiring 11.7 and 5 g/L of encapsulated Thyme Oil, respectively, to completely deactivate bacteria in milk in 4 h. The findings suggest that Thyme Oil nanoemulsions can be potentially used as natural preservatives to improve food safety.

  • Organic Thyme Oil emulsion as an alternative washing solution to enhance the microbial safety of organic cantaloupes
    Food Control, 2016
    Co-Authors: Yue Zhang, Qiumin Ma, Faith Critzer, P. Michael Davidson, Qixin Zhong
    Abstract:

    Abstract Emulsions of organic essential Oils may be used as postharvest alternative washing solutions in fresh produce production. In the present study, organic Thyme Oil was emulsified with whey protein concentrate, gum arabic, lecithin, or their equal mass mixtures without using specialized equipment. The stability of these emulsions was monitored by measuring hydrodynamic diameter during ambient storage up to 7 days. The antimicrobial activity of these emulsions against Escherichia coli O157:H7, Salmonella enterica and Listeria monocytogenes was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). All emulsions had lower MIC and MBC than free Thyme Oil pre-dissolved in ethanol. Thyme Oil emulsified with gum arabic had the smallest and most stable hydrodynamic diameter (156–239 nm) and was chosen as the washing solution to evaluate its efficacy in reducing pathogens on organic cantaloupes. Cantaloupes inoculated with pathogens were immersed in 0.1%, 0.2%, or 0.5% emulsified or free Thyme Oil for 2 min. The counts of the three cultures inoculated on cantaloupes were reduced by either 0.2% or 0.5% Thyme Oil and the emulsions were more effective than free Thyme Oil (P   0.05). During ambient storage (21 °C) up to 10 days, the counts for all three bacteria gradually declined for all treatments and the emulsion treatment had consistently lower populations than unwashed and water-washed treatments. Therefore, emulsions of organic essential Oils have potential applications as postharvest washing solutions to improve the microbiological safety of organic fresh produce.

  • Antimicrobial activity of Thyme Oil co-nanoemulsified with sodium caseinate and lecithin.
    International journal of food microbiology, 2015
    Co-Authors: Jia Xue, P. Michael Davidson, Qixin Zhong
    Abstract:

    Abstract Emulsions of essential Oils are investigated as potential intervention strategies to improve food safety and are preferably prepared from generally-recognized-as-safe emulsifiers. Stable Thyme Oil nanoemulsions can be prepared using combinations of sodium caseinate (NaCas) and soy lecithin. The objective of the present research was to study the antimicrobial activity of these nanoemulsions and understand the impacts of emulsifier concentrations. 10 g/L Thyme Oil was emulsified using combinations of (A) 4% w/v NaCas and 0.5% w/v lecithin or (B) 2% w/v NaCas and 0.25% w/v lecithin by high shear homogenization. Combination A resulted in a transparent emulsion with a mean droplet diameter of 82.5 nm, while it was turbid for the Combination B with an average diameter of 125.5 nm. Nanoemulsified Thyme Oil exhibited quicker initial reductions of bacteria than free Thyme Oil in tryptic soy broth (TSB) and 2% reduced fat milk at 21 °C, due to the improved dispersibility of Thyme Oil. In TSB with 0.3 g/L Thyme Oil, it took less than 4 and 8 h for two nanoemulsions and free Oil, respectively, to reduce Escherichia coli O157:H7 and Listeria monocytogenes to be below the detection limit. The emulsified Thyme Oil also demonstrated more significant reductions of bacteria initially (4 and 8 h) in 2% reduced fat milk than free Thyme Oil. Especially, with 4 g/L Thyme Oil, the nanoemulsion prepared with Combination A reduced L. monocytogenes to be below the detection limit after 72 h, while the free Thyme Oil treatment was only bacteriostatic and the turbid nanoemulsion treatment with Combination B resulted in about 1 log CFU/mL reduction. However, E. coli O157:H7 treated with 3 g/L emulsified Thyme Oil and Salmonella Enteritidis treated with 4 g/L emulsified Thyme Oil recovered to a higher extent in milk than free Thyme Oil treatments. The increased concentration of emulsifiers in Combination A apparently reduced the antimicrobials available to alter bacteria membrane permeability as tested by the crystal violet assay at low antimicrobial concentrations and short time (1 h). The findings suggest that nanoemulsions can be potentially used to incorporate Thyme Oil for use as antimicrobial preservatives in foods.

  • Thyme Oil nanoemulsions coemulsified by sodium caseinate and lecithin
    Journal of Agricultural and Food Chemistry, 2014
    Co-Authors: Qixin Zhong
    Abstract:

    Many nanoemulsions are currently formulated with synthetic surfactants. The objective of the present work was to study the possibility of blending sodium caseinate (NaCas) and lecithin to prepare transparent Thyme Oil nanoemulsions. Thyme Oil was emulsified using NaCas and soy lecithin individually or in combination at neutral pH by shear homogenization. The surfactant combination improved the Oil content in transparent/translucent nanoemulsions, from 1.0% to 2.5% w/v for 5% NaCas with and without 1% lecithin, respectively. Nanoemulsions prepared with the NaCas–lecithin blend had hydrodynamic diameters smaller than 100 nm and had significantly smaller and more narrowly distributed droplets than those prepared with NaCas or lecithin alone. Particle dimension and protein surface load data suggested the coadsorption of both surfactants on Oil droplets. These characteristics of nanoemulsions minimized destabilization mechanisms of creaming, coalescence, and Ostwald ripening, as evidenced by no significant cha...

  • Antimicrobial properties of nisin after glycation with lactose, maltodextrin and dextran and the Thyme Oil emulsions prepared thereof.
    International journal of food microbiology, 2014
    Co-Authors: Huaiqiong Chen, P. Michael Davidson, Qixin Zhong
    Abstract:

    Abstract To clarify the reported conflicting antimicrobial activities of nisin after glycation, nisin was glycated with lactose, maltodextrin, and dextran at 70 °C and 50% relative humidity for 1–24 h. Nisin before and after glycation was studied for the first time to prepare Thyme Oil emulsions. The activity of glycated nisin and the Thyme Oil emulsions was tested in both tryptic soy broth (TSB) and 2% reduced fat milk. Results showed that nisin glycated with a smaller saccharide for a longer duration had a higher degree of glycation and the reduced number of positive charges lowered its antibacterial activity. The emulsified Thyme Oil had an additive effect with either glycated or native nisin against Listeria monocytogenes Scott A and Bacillus subtilis in TSB and 2% reduced fat milk. However, emulsions were less effective against L. monocytogenes Scott A in milk than same units of native nisin and same concentration of free Thyme Oil, likely due to the reduced availability of thymol and carvacrol, the main components of Thyme Oil. These results showed that glycation of nisin cannot broaden its antimicrobial activity and nisin is not a good compound to prepare emulsions of essential Oils.

Lynne Mclandsborough - One of the best experts on this subject based on the ideXlab platform.

  • Effect of ripening inhibitor type on formation, stability, and antimicrobial activity of Thyme Oil nanoemulsion.
    Food chemistry, 2017
    Co-Authors: Victor Ryu, David Julian Mcclements, Maria G. Corradini, Lynne Mclandsborough
    Abstract:

    Abstract The objective of this research was to study the impact of ripening inhibitor level and type on the formation, stability, and activity of antimicrobial Thyme Oil nanoemulsions formed by spontaneous emulsification. Oil-in-water antimicrobial nanoemulsions (10 wt%) were formed by titrating a mixture of essential Oil, ripening inhibitor, and surfactant (Tween 80) into 5 mM sodium citrate buffer (pH 3.5). Stable nanoemulsions containing small droplets ( d  canola > coconut which also depended on their ability to transfer hydrophobic antimicrobial constituents to the separated hydrophobic domain.

  • fabrication stability and efficacy of dual component antimicrobial nanoemulsions essential Oil Thyme Oil and cationic surfactant lauric arginate
    Food Chemistry, 2015
    Co-Authors: Yuhua Chang, David Julian Mcclements, Lynne Mclandsborough
    Abstract:

    The influence of a cationic surfactant (lauric arginate, LAE) on the physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions was investigated. Nanoemulsions prepared from pure Thyme Oil were highly unstable due to Ostwald ripening, but they could be stabilized by adding a ripening inhibitor (corn Oil) to the Oil phase prior to homogenisation. The loading capacity and antimicrobial efficacy of Thyme Oil nanoemulsions were significantly increased by adding LAE. In the absence of LAE, at least 60 wt% corn Oil had to be added to the lipid phase to inhibit Ostwald ripening; but in the presence of 0.1 wt% LAE, only 30 wt% corn Oil was needed. LAE addition substantially increased the antimicrobial efficacy of the Thyme Oil nanoemulsions: 200 μg/ml Thyme Oil was needed to inhibit growth of a spOilage yeast (Zygosaccharomyces bailii) if LAE was added, whereas ⩾ 400 μg/ml was needed in the absence of LAE.

  • physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions influence of ripening inhibitors
    Journal of Agricultural and Food Chemistry, 2012
    Co-Authors: Yuhua Chang, Lynne Mclandsborough, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions (pH 3.5) were prepared as potential antimicrobial delivery systems. The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of Thyme Oil. Ostwald ripening could be inhibited by mixing Thyme Oil with a water-insoluble ripening inhibitor (≥60 wt % corn Oil or ≥50 wt % MCT in the lipid phase) before homogenization, yielding nanoemulsions with good physical stability. Physically stable Thyme Oil nanoemulsions were examined for their antimicrobial activities against an acid-resistant spOilage yeast, Zygosaccharomyces bailii (ZB). Oil phase composition (ripening inhibitor type and concentration) had an appreciable influence on the antimicrobial activity of the Thyme Oil nanoemulsions. In general, increasing the ripening inhibitor levels in the lipid phase reduced the antimicrobial efficacy of nanoemulsions. For example, for nanoemulsions containing 60 wt % corn Oil in the ...

  • physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions influence of ripening inhibitors
    Journal of Agricultural and Food Chemistry, 2012
    Co-Authors: Yuhua Chang, Lynne Mclandsborough, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions (pH 3.5) were prepared as potential antimicrobial delivery systems. The nanoemulsions were highly unstable to droplet growth and phase separation, which was attribu...

  • influence of surfactant charge on antimicrobial efficacy of surfactant stabilized Thyme Oil nanoemulsions
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Khalid Ziani, Lynne Mclandsborough, Yuhua Chang, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions stabilized by a nonionic surfactant (Tween 80, T80) were prepared as potential antimicrobial delivery systems (pH 4). The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of Thyme Oil. Ostwald ripening could be inhibited by incorporating ≥75% of corn Oil (a hydrophobic material with a low water solubility) into the nanoemulsion droplets. The electrical characteristics of the droplets in the nanoemulsions were varied by incorporating ionic surfactants with different charges after homogenization: a cationic surfactant (lauric arginate, LAE) or an anionic surfactant (sodium dodecyl sulfate, SDS). The antifungal activity of nanoemulsions containing positive, negative, or neutral thymol droplets was then conducted against four strains of acid-resistant spOilage yeasts: Zygosaccharomyces bailli, Saccharomyces cerevisiae, Brettanomyces bruxellensis, and Brettanomyces naardenensis. The antifungal properties of the three surfactants (T80, LAE, SDS) were also tested in the absence of thymol droplets. Both ionic surfactants showed strong antifungal activity in the absence of thymol droplets, but no antimicrobial activity in their presence. This effect was attributed to partitioning of the antimicrobial surfactant molecules between the Oil droplet and microbial surfaces, thereby reducing the effective concentration of active surfactants available to act as antimicrobials. This study shows Oil droplets may decrease the efficacy of surfactant-based antimicrobials, which has important consequences for formulating effective antimicrobial agents for utilization in emulsion-based food and beverage products.

Yuhua Chang - One of the best experts on this subject based on the ideXlab platform.

  • fabrication stability and efficacy of dual component antimicrobial nanoemulsions essential Oil Thyme Oil and cationic surfactant lauric arginate
    Food Chemistry, 2015
    Co-Authors: Yuhua Chang, David Julian Mcclements, Lynne Mclandsborough
    Abstract:

    The influence of a cationic surfactant (lauric arginate, LAE) on the physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions was investigated. Nanoemulsions prepared from pure Thyme Oil were highly unstable due to Ostwald ripening, but they could be stabilized by adding a ripening inhibitor (corn Oil) to the Oil phase prior to homogenisation. The loading capacity and antimicrobial efficacy of Thyme Oil nanoemulsions were significantly increased by adding LAE. In the absence of LAE, at least 60 wt% corn Oil had to be added to the lipid phase to inhibit Ostwald ripening; but in the presence of 0.1 wt% LAE, only 30 wt% corn Oil was needed. LAE addition substantially increased the antimicrobial efficacy of the Thyme Oil nanoemulsions: 200 μg/ml Thyme Oil was needed to inhibit growth of a spOilage yeast (Zygosaccharomyces bailii) if LAE was added, whereas ⩾ 400 μg/ml was needed in the absence of LAE.

  • physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions influence of ripening inhibitors
    Journal of Agricultural and Food Chemistry, 2012
    Co-Authors: Yuhua Chang, Lynne Mclandsborough, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions (pH 3.5) were prepared as potential antimicrobial delivery systems. The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of Thyme Oil. Ostwald ripening could be inhibited by mixing Thyme Oil with a water-insoluble ripening inhibitor (≥60 wt % corn Oil or ≥50 wt % MCT in the lipid phase) before homogenization, yielding nanoemulsions with good physical stability. Physically stable Thyme Oil nanoemulsions were examined for their antimicrobial activities against an acid-resistant spOilage yeast, Zygosaccharomyces bailii (ZB). Oil phase composition (ripening inhibitor type and concentration) had an appreciable influence on the antimicrobial activity of the Thyme Oil nanoemulsions. In general, increasing the ripening inhibitor levels in the lipid phase reduced the antimicrobial efficacy of nanoemulsions. For example, for nanoemulsions containing 60 wt % corn Oil in the ...

  • physical properties and antimicrobial efficacy of Thyme Oil nanoemulsions influence of ripening inhibitors
    Journal of Agricultural and Food Chemistry, 2012
    Co-Authors: Yuhua Chang, Lynne Mclandsborough, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions (pH 3.5) were prepared as potential antimicrobial delivery systems. The nanoemulsions were highly unstable to droplet growth and phase separation, which was attribu...

  • influence of surfactant charge on antimicrobial efficacy of surfactant stabilized Thyme Oil nanoemulsions
    Journal of Agricultural and Food Chemistry, 2011
    Co-Authors: Khalid Ziani, Lynne Mclandsborough, Yuhua Chang, David Julian Mcclements
    Abstract:

    Thyme Oil-in-water nanoemulsions stabilized by a nonionic surfactant (Tween 80, T80) were prepared as potential antimicrobial delivery systems (pH 4). The nanoemulsions were highly unstable to droplet growth and phase separation, which was attributed to Ostwald ripening due to the relatively high water solubility of Thyme Oil. Ostwald ripening could be inhibited by incorporating ≥75% of corn Oil (a hydrophobic material with a low water solubility) into the nanoemulsion droplets. The electrical characteristics of the droplets in the nanoemulsions were varied by incorporating ionic surfactants with different charges after homogenization: a cationic surfactant (lauric arginate, LAE) or an anionic surfactant (sodium dodecyl sulfate, SDS). The antifungal activity of nanoemulsions containing positive, negative, or neutral thymol droplets was then conducted against four strains of acid-resistant spOilage yeasts: Zygosaccharomyces bailli, Saccharomyces cerevisiae, Brettanomyces bruxellensis, and Brettanomyces naardenensis. The antifungal properties of the three surfactants (T80, LAE, SDS) were also tested in the absence of thymol droplets. Both ionic surfactants showed strong antifungal activity in the absence of thymol droplets, but no antimicrobial activity in their presence. This effect was attributed to partitioning of the antimicrobial surfactant molecules between the Oil droplet and microbial surfaces, thereby reducing the effective concentration of active surfactants available to act as antimicrobials. This study shows Oil droplets may decrease the efficacy of surfactant-based antimicrobials, which has important consequences for formulating effective antimicrobial agents for utilization in emulsion-based food and beverage products.

Wu Feng - One of the best experts on this subject based on the ideXlab platform.

  • Controlled Release Mechanism and Antibacterial Effect of Layer-By-Layer Self-Assembly Thyme Oil Microcapsule.
    Journal of food science, 2019
    Co-Authors: Zhao Zhang, Wu Feng, Shanshan Zhang, Die Xiong, Jiaping Chen
    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.; © 2019 Institute of Food Technologists®.

  • Physical Properties and Stabilization of Microcapsules Containing Thyme Oil by Complex Coacervation
    Journal of food science, 2016
    Co-Authors: Lili Shen, Jiaping Chen, Youju Bai, Jing Huang, Wu Feng
    Abstract:

    The aim of this study was to produce and characterize microcapsules of Thyme Oil and finally appraise the extent of stability improvement. The optimum process conditions obtained from orthogonal tests were as follows: ratio of core material to wall 0.5, temperature 40 °C, pH value 3.0 and time 20 min, where the practical encapsulation efficiency was 85.17±1.35%. The microcapsules belong to the nanometric range as the average particle diameter was 531.17±77.12 nm. The results from structural analysis indicated that no significant chemical bond occurred during the encapsulation process and the microcapsules remained stable when the encapsulation was conducted at a temperature below 53.1 °C. Especially, the retention rate of Thyme Oil in microcapsules remained 39.21% at 4 °C, 36.99% at 25 °C and 33.80% at 40 °C after 30 d of storage. Moreover, protection from light exposure presented a positive impact on the storage stability of Thyme Oil microcapsules.

  • Thyme Oil to control Alternaria alternata in vitro and in vivo as fumigant and contact treatments
    Food Control, 2011
    Co-Authors: Wu Feng, Jiaping Chen, Xiaodong Zheng, Qing Liu
    Abstract:

    Abstract This study was conducted to evaluate the efficacy of Thyme Oil in suppressing Alternaria alternata (Fr.:Fr.) Keissl in vitro and in vivo as fumigant and contact treatments. Thyme Oil possessed great fumigant and contact toxicity against A. alternata at different concentrations in vitro. Irreversible inhibition of fungal growth could be caused by exposure to 500 μL/L Thyme Oil as a fumigant for 6 and 12 days. The spores of A. alternata were completely suppressed 6 h after incubation in potato dextrose broth (PDB) by 2000 μL/L of Thyme Oil. The Thyme Oil as a fumigant at 66.7 μL/L showed a significant inhibition effect on A. alternata of cherry tomatoes stored at 25 °C for 5 days. Thyme Oil at 500 μL/L showed a significant contact inhibition effect on A. alternata of cherry tomatoes stored at 25 °C for 3 days.

  • Effect of potato starch-based antibacterial composite films with Thyme Oil microemulsion or microcapsule on shelf life of chilled meat
    LWT, 1
    Co-Authors: Lanyu Yuan, Wu Feng, Zhao Zhang, Peng Yunyan, Xiao Yao, Jiaping Chen
    Abstract:

    Abstract chilled meat is extremely susceptible to microbial contamination during processing and storage. Therefore, a new edible starch-based antibacterial composite film with Thyme Oil microemulsions(ME) or microcapsules(TMS) was prepared. The slow-release characteristic, bacteriostatic property and the preservation effect on chilled meat of the films were evaluated. The results showed that the cumulative release rates of composite films containing 5% microemulsion and 5% microcapsule were much less than the film containing 5% Thyme Oil. The antibacterial effect of film containing Thyme Oil microemulsion (ME-S) was stronger than that of film containing Thyme Oil microcapsule (TMS-S), but both of their antibacterial effect increased as the concentration increased. The overall fresh-keeping effect of composite films on chilled meat at 0-4 was blank