Nanostructured Encapsulation Systems

Weiß, Jochen; Gaysinsky, Sylvia; Davidson, Michael; McClements, Julian

doi:10.1016/b978-0-12-374124-0.00024-7

Cited by 123 publications

(104 citation statements)

References 134 publications

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“…The subcellular diameter (Ͻ50 nm) of eugenol-lecithin complexes of observed aggregates at the lecithin critical concentration can also partially explain the increased bioactivity, as it was previously suggested that the absorption of essential oil into microbial cells was driven by passive diffusion (34,35). The resistance to mass transfer when passive diffusion is the dominant mechanism can be reduced by decreasing the size of hydrophobic components, thus enhancing cellular absorption (9,36). In our study, the homogeneous nanometer-scale eugenol-lecithin complexes with lecithin at critical concentration would promote passive absorption of eugenol into E. coli cells, resulting in enhanced antimicrobial activity.…”

Section: Discussionmentioning

confidence: 89%

Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli

Zhang

Dudley

Davidson

et al. 2017

Appl Environ Microbiol

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Lecithin is a natural emulsifier used in a wide range of food and nonfood applications to improve physical stability, with no known bioactive effects. In this study, the effect of lecithin on the antimicrobial performance of a constant eugenol concentration was tested against three Escherichia coli strains (C600, 0.1229, and O157:H7 strain ATCC 700728). This is the first study, to our knowledge, focusing on lecithin at concentrations below those commonly used in foods to improve the stability of oil in water emulsions (Յ10 mg/100 ml). For all three cultures, significant synergistic antimicrobial effects were observed when E. coli cultures were exposed to a constant eugenol concentration (ranging from 0.043 to 0.050% [wt/wt]) together with critical lecithin concentrations ranging from 0.5 to 1 mg/100 ml. Increasing the concentration of lecithin above 1 mg/100 ml (up to 10 mg/100 ml lecithin) diminished the antibacterial effect to values similar to those with eugenol-only treatments. The formation of aggregates (Ͻ100 nm) at the critical lecithin concentration was observed using cryo-transmission electron microscopy (cryo-TEM), together with a reduction in light absorbance at 284 nm. At critically low concentrations of lecithin, the formation of nanoscale aggregates is responsible for improving eugenol antimicrobial effects.IMPORTANCE Essential oils (EOs) are effective natural antimicrobials. However, their hydrophobicity and strong aromatic character limit the use of essential oils in food systems. Emulsifiers (e.g., lecithin) increase the stability of EOs in water-based systems but fail to consistently improve antimicrobial effects. We demonstrate that lecithin, within a narrow critical concentration window, can enhance the antimicrobial properties of eugenol. This study highlights the potential bioactivity of lecithin when utilized to effectively control foodborne pathogens.

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Section: Discussionmentioning

confidence: 89%

Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli

Zhang

Dudley

Davidson

et al. 2017

Appl Environ Microbiol

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“…The essential oils (EOs) are highly aromatic and volatile liquids, usually extracted from the bark, leaves, stem or leaves of herbs and spices, with excellent antioxidant and antimicrobial properties. Also, they have reported against a broad spectrum of bacteria and fungi (Weiss et al 2009;Burt 2004).…”

Section: Introductionmentioning

confidence: 99%

Nanoemulsion of orange oil with non ionic surfactant produced emulsion using ultrasonication technique: evaluating against food spoilage yeast

et al. 2015

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In recent years, food industries have shown great interest in developing nanoemulsion (NE) using essential oils (EOs) to prevent food spoilage caused by microorganisms. The hydrophobic properties of EOs have lead to reduced solubilization effect of food, which in turn, created a negative impact on the quality of food and its antimicrobial efficacy. Focusing this issue, we attempted a unique NE preparation using orange oil, Tween 80 (organic phase) and water (aqueous phase) by sonication technique. Based on thermodynamic stability studies, the effective diameter was reported to be in the size range from 20 to 30 nm. Saccharomyces cerevisiae was used in testing the anti-yeast effect. Their activity was studied in both growth medium and apple juice. The minimum inhibitory concentration of this NE was determined using broth dilution method. At 2 ll/ml, orange oil NE demonstrated inhibition of tested microorganisms. The kinetics of killing curve, have shown that the NE treated cells had lost its viability within 30 min of interaction. Also, SEM image revealed that the treated cells became distorted in comparison to their control cells. NE treated apple juice showed complete loss of viability even on dilution as compared to their controls.

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“…Because of its limited water solubility, estimated to be 1 g/liter at 20°C (7), the undissolved thymol applied at a concentration above the solubility limit impacts visual quality and antimicrobial availability. Being a volatile EO component, thymol also has an intense spicy/medicinal aroma, particularly upon heating, thus adversely affecting sensory properties of foods upon incorporation in the free form or at high concentrations (8,19,28,34).…”

mentioning

confidence: 99%

“…Smaller particles scatter visible light less effectively and can eventually enable transparent dispersions at a sufficiently small dimension (35). The solubility of compounds with limited solubility increases when dispersed in a smaller structure (22), which, along with increased surface area for bacterial contact and even distribution in food matrices, improves the antimicrobial effectiveness (34). Proof of concept has been given by liposomal delivery systems containing carvacrol (28) and nanoscale surfactant micelles containing eugenol (16) when tested in growth media and milk.…”

mentioning

confidence: 99%

Nanocapsular Dispersion of Thymol for Enhanced Dispersibility and Increased Antimicrobial Effectiveness against Escherichia coli O157:H7 and Listeria monocytogenes in Model Food Systems

Shah

Davidson

Zhong

2012

Appl Environ Microbiol

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Essential oils are marginally soluble in water, making it challenging to evenly disperse them in foods and resulting in an increased tendency to bind with food lipids and proteins, resulting in lowered antimicrobial efficacy. In the current study, free and nano-dispersed (ND) thymol were compared in terms of their antimicrobial efficacies against Escherichia coli O157:H7 ATCC 43889 and 43894 and Listeria monocytogenes strains Scott A and 101 in apple cider and 2% reduced-fat milk. Apple cider was adjusted to pHs 5.5 and 3.5, and antimicrobial tests were performed at 0.3-, 0.5-, 0.75-, and 1.0-g/liter thymol concentrations at 35, 32, 25, and 4°C. Overall, 0.5 and 1.0 g/liter thymol in nano-dispersion and along with free thymol were inhibitory and bactericidal, respectively, against bacterial strains under all treatment conditions. At pH 5.5, 0.5 g/liter ND thymol was bacteriostatic against L. monocytogenes and E. coli for up to 48 h. At pH 3.5, L. monocytogenes controls did not survive beyond 12 h but E. coli survived and was inhibited by 0.5 g/liter ND thymol after 12 and 48 h in apple cider. E. coli strains were significantly sensitive to 4°C and pH 3.5 (P < 0.05). When bacteria were tested in 2% reduced-fat milk at 35 or 32°C, ND and free thymol demonstrated inhibition at 4.5 g/liter. Thus, the current technology seems to be promising and novel, enabling thymol-containing nano-dispersions that are not only transparent but also effective against pathogens in food applications, especially in clear beverages.

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Nanostructured Encapsulation Systems

Cited by 123 publications

References 134 publications

Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli

Critical Concentration of Lecithin Enhances the Antimicrobial Activity of Eugenol against Escherichia coli

Nanoemulsion of orange oil with non ionic surfactant produced emulsion using ultrasonication technique: evaluating against food spoilage yeast

Nanocapsular Dispersion of Thymol for Enhanced Dispersibility and Increased Antimicrobial Effectiveness against Escherichia coli O157:H7 and Listeria monocytogenes in Model Food Systems

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