Nanoencapsulation of Oliveria decumbens Vent./basil essential oils into gum arabic/maltodextrin: Improved in vitro bioaccessibility and minced beef meat safety

This study investigated the functional properties of freeze-dried encapsulated Oliveria decumbens Vent. (OEO) and basil (BEO) essential oils (EOs) in maltodextrin/gum arabic coating solution (1:1). Nanoencapsulated EOs were evaluated in terms of size, polydispersity, encapsulation efficiency, morphology, antioxidant, and antibacterial activities (AOA and ABA), and sensory characteristics in vitro compared to the control. The TPC (30.43 to 32.41 mg GAE/g DW) and AOA (25.97 to 26.42 %) were determined in free and encapsulated OEO, and ABA was observed, which were higher than BEO. Both free and encapsulated OEO and BEO demonstrated significant ABA against various Gram-positive and Gram-negative bacteria, with MIC values ranging from 0.25 to 1.25 mg/mL and MBC values ranging from 1.00 to 3.00 mg/mL. In minced meat, both free and encapsulated oils effectively reduced bacterial counts during refrigerated storage, with log reductions ranging from 1.00 to 6.48 CFU/g. Additionally, the pH and thiobarbituric acid values in meat samples were better maintained with the addition of oils. Sensory analysis showed that the encapsulated oils effectively masked their natural flavor and aroma, making them suitable for incorporation into food. Finally, OEO and BEO nanocapsules can improve the standard and safety of meat products due to their antioxidant and antibacterial properties.

Oregano essential oil encapsulated in zein-pectin-chitosan nanoparticles to improve the storage quality of Harbin red sausage

In this study, the effect of oregano essential oil loaded in zein-pectin-chitosan (Zein-PC-CS-OEO) nanoparticles on the quality of Harbin red sausage during storage was examined. Zein-PC-CS-OEO nanoparticles exhibit the better encapsulation efficiency, antioxidant and antibacterial properties than these of other prepared nanoparticles, which were subsequently incorporated into Harbin red sausage with different concentrations. The physicochemical properties, bacterial community structure, and flavor characteristics of the Harbin red sausage were determined. Both thiobarbituric acid values and the growth of dominant spoilage bacteria in Harbin red sausage are inhibited by Zein-PC-CS-OEO nanoparticles, while the total aerobic bacteria count is reduced. These results indicate that the storage quality of Harbin red sausage is improved by Zein-PC-CS-OEO nanoparticles. It is worth noting that the shelf life of Harbin red sausage supplemented with 0.1 % Zein-PC-CS-OEO nanoparticles is extended to 9 d, and the flavor characteristics of which are better maintained. This study provides a new approach to extend the application of essential oil and improve the storage quality of Harbin red sausage.

Plant-based essential oil encapsulated in nanoemulsions and their enhanced therapeutic applications: An overview

In recent years, studies on the formulation of nanoemulsions have been the focus of attention due to their potential applicability in food, pharmaceuticals, cosmetics, and agricultural industries. Nanoemulsions can be formulated using ingredients approved by the Food and Drug Administration (FDA), which assures their safety profiles to a great extent. Bioactive compounds such as essential oils although have strong biological properties and antimicrobial compounds, their usage is restricted due to their high volatility, instability, and hydrophobic nature. Therefore, nanoemulsion as carrier vehicle can be used to encapsulate essential oils to obtain stable and enhanced physicochemical characteristics of the essential oils. This review details the structure, formulation, and characterization techniques used for nanoemulsions, with a focus on the essential oil-based nanoemulsions which have the potential to be used as antimicrobial and anticancer therapeutics.

Effects of three essential oils and their nano-emulsions on Listeria monocytogenes and Shigella flexneri in Egyptian Talaga cheese

Talaga cheese is a soft Egyptian cheese that has been associated with foodborne pathogens such as Listeria monocytogenes and Shigella flexneri. Essential oils (EOs) play a pivotal role in sustainably controlling foodborne diseases and as a potential preservative in soft cheeses. However, limited data is available comparing the antibacterial activity of EOs and their nano-emulsions (NEs) when inoculated into Talaga cheese. Therefore, this study aimed to examine the antibacterial activity of carvacrol, clove, and cumin EOs, in addition to their NEs, against L. monocytogenes (NCTC 13372/ATCC® 7644) and S. flexneri (ATCC®12022^TW⁎) inoculated into laboratory-manufactured Egyptian Talaga cheese during refrigerated storage. The NEs had a Z-average diameter of 32.98 ± 29.75 nm, 45.2 ± 34.25 nm, and 50.23 ± 15.7 nm and a PDI of 0.326, 0.245, and 0.307 for carvacrol, clove, and cumin NEs, respectively. The flow of active functional groups of EOs and NEs as clarified by Fourier-transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM) showed the spherical-shaped droplet structure of the prepared NEs. The minimum inhibitory concentration (MIC) of all EOs and their NEs was 0.78% against L. monocytogenes and 1.56% against S. flexneri, while those of carvacrol EO and its NE were 0.78% against both microorganisms. By supplementation in cheese, NEs significantly reduced the counts of inoculated pathogens from 8.2 log₁₀cfu/g to 1.5 log₁₀cfu/g after 2 to 3 weeks compared to EOs, which reduced them after 4 to 5 weeks. The carvacrol NE showed excellent antibacterial activity with no cheese sensory impairment. It reduced L. monocytogenes by 99% (R%) after 7 days and after 3 weeks for S. flexneri at 0.78% concentration, while higher concentrations and a longer period were required for the other NEs to show an inhibitory effect. NEs showed a greater antimicrobial effect than their non-emulsified counterparts, especially when interacting with food items, and carvacrol NE at a low concentration (0.78%) demonstrated its efficacy as an antibacterial and natural food preservative.

Novel Clove Essential Oil Nanoemulgel Tailored by Taguchi's Model and Scaffold-Based Nanofibers: Phytopharmaceuticals with Promising Potential as Cyclooxygenase-2 Inhibitors in External Inflammation

PURPOSE

Clove essential oil is a phytochemical possessing a vast array of biological activities. Nevertheless, fabricating nano topical delivery systems targeted to augment the anti-inflammatory activity of the oil has not been investigated so far. Accordingly, in this study, controlled release nanoparticulate systems, namely nanoemulgel and nanofibers (NFs), of the oil were developed to achieve such goal.

METHODS

The nanoemulsion was incorporated in the hydrogel matrix of mixed biopolymers - chitosan, guar gum and gum acacia - to formulate nanoemulsion-based nanoemulgel. Taguchi's model was adopted to evaluate the effect of independently controlled parameters, namely, the concentration of chitosan (X1), guar gum (X2), and gum acacia (X3) on different dependently measured parameters. Additionally, the nanoemulsion-based NFs were prepared by the electrospinning technique using polyvinyl alcohol (PVA) polymer. Extensive in vitro, ex vivo and in vivo evaluations of the aforementioned formulae were conducted.

RESULTS

Both Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) established the complete dispersion of the nanoemulsion in the polymeric matrices of the prepared nanoemulgel and NFs. The ex vivo skin permeation data of clove essential oil from the prepared formulations showed that NFs can sustain its penetration through the skin comparably with nanoemulgel. Topical treatment with NFs (once application) and nanoemulgel (twice application) evoked a marvelous in vivo anti-inflammatory activity against croton oil-induced mouse skin inflammation model when compared with pure clove essential oil along with relatively higher efficacy of medicated NFs than that of medicated nanoemulgel. Such prominent anti-inflammatory activity was affirmed by histopathological and immunohistochemical examinations.

CONCLUSION

These results indicated that nanoemulsion-based nanoemulgel and nanoemulsion-based NFs could be introduced to the phytomedicine field as promising topical delivery systems for effective treatment of inflammatory diseases instead of nonsteroidal anti-inflammatory drugs that possess adverse effects.