Antimicrobial influence of nanoemulsified lemon essential oil and pure lemon essential oil on food-borne pathogens and fish spoilage bacteria

Nobiletin enhances the antifungal activity of eugenol nanoemulsion against Penicillium italicum in both in vitro and in vivo settings

The study prepared and used eugenol nanoemulsion loaded with nobiletin as fungistat to study its antifungal activity and potential mechanism of Penicillium italicum (P. italicum). The results showed that the minimum inhibitory concentration (MIC) of eugenol nanoemulsion loaded with nobiletin (EGN) was lower than that of pure eugenol nanoemulsion (EG), which were 160 μg/mL and 320 μg/mL, respectively. At the same time, the mycelial growth inhibition rate of EGN nanoemulsion (54.68 %) was also higher than that of EG nanoemulsion (9.92 %). This indicates that EGN nanoemulsion is more effective than EG nanoemulsion. Compared with EG nanoemulsion, the treatment of EGN nanoemulsion caused more serious damage to the cell structure of P. italicum. At the same time, in vitro inoculation experiments found that EGN nanoemulsion has better control and delay the growth and reproduction of P. italicum in citrus fruits. And the results reflected that EGN nanoemulsion may be considered as potential resouces of natural antiseptic to inhibit blue mold disease of citrus fruits, because it has good antifungal activity.

Antioxidant and antimicrobial effect of sodium alginate nanoemulsion coating enriched with oregano essential oil (Origanum vulgare L.) and Trachyspermum ammi oil (Carum cupticum) on food pathogenic bacteria

Today, microbial contamination in food is one of the major problems of the food industry and public health in general around the world. Foodborne illnesses, such as diarrheal diseases, kill many people around the world each year. The general objective of this study was to evaluate the antioxidant and antibacterial activity of sodium alginate nanoemulsion coating incorporated with oregano essential oil (Origanum vulgare L.) and Trachyspermum ammi oil (Carum cupticum) on Escherichia coli, and Listeria monocytogenes. To achieve this study, fresh chicken meat was used for this experiment. Listeria monocytogenes ATCC 19111 and Escherichia coli ATCC 35218 were obtained from the American Type Culture Collection (Manassas, VA, USA). After the preparation of the essential oil, the chemical composition of this essential oil was determined by using (GC-MS). The physicochemical properties of the nanoemulsion essential oil prepared were characterized and their antimicrobial activity was evaluated. The results showed that the GC-MS analysis of the volatile constituents of the Origanum vulgare essential oil compounds allowed the identification of 19 compounds representing 93.72% of the total oil. The major components detected in Origanum vulgare essential oil were pulegone (49.25%), eucalyptol (18.23%), and menthone (12.37%). About the Carum cupticum essential oil, 21 compounds representing 98.5% of the total oil were identified. The major components detected in Origanum vulgare essential oil were thymol (23.3%), p-cymene (17.5%), and γ-terpinene (16.8%). The best z-average (d.nm) is 483.4 nm (Carum cupticum essential oil + nano) followed by 470.1 nm (nanochitosan). The results of the antimicrobial test showed that the different preparations have a good inhibitory activity for the in vitro growth of Escherichia coli and Listeria monocytogenes. According to the MIC and MBC results of this study, the nanoemulsion also presented a good bacteriostatic activity against the two pathogenic bacteria tested in this study.

Foeniculum vulgare essential oil nanoemulsion inhibits Fusarium oxysporum causing Panax notoginseng root-rot disease

Background

Fusarium oxysporum (F. oxysporum) is the primary pathogenic fungus that causes Panax notoginseng (P. notoginseng) root rot disease. To control the disease, safe and efficient antifungal pesticides must currently be developed.

Methods

In this study, we prepared and characterized a nanoemulsion of Foeniculum vulgare essential oil (Ne-FvEO) using ultrasonic technology and evaluated its stability. Traditional Foeniculum vulgare essential oil (T-FvEO) was prepared simultaneously with 1/1000 Tween-80 and 20/1000 dimethyl sulfoxide (DMSO). The effects and inhibitory mechanism of Ne-FvEO and T-FvEO in F. oxysporum were investigated through combined transcriptome and metabolome analyses.

Results

Results showed that the minimum inhibitory concentration (MIC) of Ne-FvEO decreased from 3.65 mg/mL to 0.35 mg/mL, and its bioavailability increased by 10-fold. The results of gas chromatography/mass spectrometry (GC/MS) showed that T-FvEO did not contain a high content of estragole compared to Foeniculum vulgare essential oil (FvEO) and Ne-FvEO. Combined metabolome and transcriptome analysis showed that both emulsions inhibited the growth and development of F. oxysporum through the synthesis of the cell wall and cell membrane, energy metabolism, and genetic information of F. oxysporum mycelium. Ne-FvEO also inhibited the expression of 2-oxoglutarate dehydrogenase and isocitrate dehydrogenase and reduced the content of 2-oxoglutarate, which inhibited the germination of spores.

Conclusion

Our findings suggest that Ne-FvEO effectively inhibited the growth of F. oxysporum in P. notoginseng in vivo. The findings contribute to our comprehension of the antifungal mechanism of essential oils (EOs) and lay the groundwork for the creation of plant-derived antifungal medicines.

Citrus limon Essential Oil: Chemical Composition and Selected Biological Properties Focusing on the Antimicrobial (In Vitro, In Situ), Antibiofilm, Insecticidal Activity and Preservative Effect against Salmonella enterica Inoculated in Carrot

New goals for industry and science have led to increased awareness of food safety and healthier living in the modern era. Here, one of the challenges in food quality assurance is the presence of pathogenic microorganisms. As planktonic cells can form biofilms and go into a sessile state, microorganisms are now more resistant to broad-spectrum antibiotics. Due to their proven antibacterial properties, essential oils represent a potential option to prevent food spoilage in the search for effective natural preservatives. In this study, the chemical profile of Citrus limon essential oil (CLEO) was evaluated. GC-MS analysis revealed that limonene (60.7%), β-pinene (12.6%), and γ-terpinene (10.3%) are common constituents of CLEO, which prompted further research on antibacterial and antibiofilm properties. Minimum inhibitory concentration (MIC) values showed that CLEO generally exhibits acceptable antibacterial properties. In addition, in situ antimicrobial research revealed that vapour-phase CLEO can arrest the growth of Candida and Y. enterocolitica species on specific food models, indicating the potential of CLEO as a preservative. The antibiofilm properties of CLEO were evaluated by MIC assays, crystal violet assays, and MALDI-TOF MS analysis against S. enterica biofilm. The results of the MIC and crystal violet assays showed that CLEO has strong antibiofilm activity. In addition, the data obtained by MALDI-TOF MS investigation showed that CLEO altered the protein profiles of the bacteria studied on glass and stainless-steel surfaces. Our study also found a positive antimicrobial effect of CLEO against S. enterica. The anti-Salmonella activity of CLEO in vacuum-packed sous vide carrot samples was slightly stronger than in controls. These results highlight the advantages of the antibacterial and antibiofilm properties of CLEO, suggesting potential applications in food preservation.

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.

Progress of nanopreparation technology applied to volatile oil drug delivery systems

Traditional Chinese medicine volatile oil has a long history and possesses extensive pharmacological activity. However, volatile oils have characteristics such as strong volatility, poor water solubility, low bioavailability, and poor targeting, which limit their application. The use of volatile oil nano drug delivery systems can effectively improve the drawbacks of volatile oils, enhance their bioavailability and chemical stability, and reduce their volatility and toxicity. This article first introduces the limitations of the components of traditional Chinese medicine volatile oils, discusses the main classifications and latest developments of volatile oil nano formulations, and briefly describes the preparation methods of traditional Chinese medicine volatile oil nano formulations. Secondly, the limitations of nano formulation technology are discussed, along with future challenges and prospects. A deeper understanding of the role of nanotechnology in traditional Chinese medicine volatile oils will contribute to the modernization of volatile oils and broaden their application value.

Spontaneous nanoemulsification of cinnamon essential oil: Formulation, characterization, and antibacterial and antibiofilm activity against fish spoilage caused by Serratia rubidaea BFMO8

The contemporary food industry's uses of nanoemulsions (NEs) include food processing, effective nutraceutical delivery, the development of functional chemicals, and the synthesis of natural preservatives, such as phytocompounds. Although cinnamon essential oil (CEO) is widely used in the cosmetic, pharmaceutical, and food industries, it is difficult to add to aqueous-based food formulations due to its weak stability and poor water solubility. This study describes the formulation of a CEO nanoemulsion (CEONE) by spontaneous emulsification and evaluates its antibacterial and antibiofilm properties against biofilm-forming Serratia rubidaea BFMO8 isolated from spoiled emperor fish (Lethrinus miniatus). Bacteria causing spoilage in emperor fish were isolated and identified as S. rubidaea using common morphological, cultural, and 16S RNA sequencing methods, and their ability to form biofilms and their susceptibility to CEONE were assessed using biofilm-specific methods. The spontaneous emulsification formulation of CEONE was accomplished using water and Tween 20 surfactant by manipulating organic and aqueous phase interface properties and controlling particle growth by capping surfactant increases. The best emulsification, with highly stable nano-size droplets, was accomplished at 750 rpm and a 1:3 ratio concentration. The stable CEONE droplet size, polydispersity index, and zeta potential values were 204.8 nm, 0.115, and -6.05 mV, respectively. FTIR and high-resolution liquid chromatography-mass spectrometry (HR-LCMS) analyses have revealed carboxyl, carbonyl, and phenol-like primary phytochemical functional groups in CEO and CEONE, which contribute to their antibacterial and antibiofilm properties.

Development, characterization and functional properties of sodium alginate-based films incorporated with Schisandra chinensis extract-natamycin complex

Because of the impact of petroleum-based polymers on environmental deterioration and the need for safe, efficient, and functional packaging films, a sodium alginate (SA)-based film incorporating a Schisandra chinensis extract (SCE)-natamycin (NA) complex was developed for the desired physical and functional properties. The incorporation of SCE-NA into SA-based films decreased the water vapor transmission rate (WVTR), moisture content (MC), and hydrophilicity of the films and improved their opacity, elongation at break (EAB), and thermal stability. Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), X-ray photoelectron spectroscopy (XPS), and X-ray Diffraction (XRD) analyses showed that SA, SCE, and NA had positive interactions and compatibility. In addition, the antimicrobial activity analysis indicated that the SA-SCE-NA film-forming solutions had satisfactory antimicrobial activity against Staphylococcus aureus, Escherichia coli, Saccharomyces cerevisiae, and Aspergillus niger. SA-based composite films have been used to coat cucumbers and blueberries to extend their shelf life. Compared to the neat SA film, the shelf life of cucumbers treated with the SA-SCE-NA film increased by 6 days compared to that in the untreated group at 28 °C, and the shelf life of blueberries increased by 5 days at 4 °C, revealing its potential utilization in food packaging.

Citrus essential oils - Based nano-emulsions: Functional properties and potential applications

Citrus essential oils are natural products with various bioactive properties (e.g., antimicrobial, antioxidant, and antimutagenic activities), that are generally recognized as safe (GRAS) by Food and Drug Administration (FDA) to be used as flavorings and food additives. Nonetheless, due to their high volatility, low solubility in water, low thermal stability, susceptibility to oxidation, and strong flavor, their applications in the food industry are limited. Nanotechnology allows the incorporation of citrus essential oils into nano-emulsion systems, thus protecting them from the deterioration caused by external factors and maintaining or even improving their functional properties. This study aims to summarize the antioxidant, antimicrobial, and antimutagenic effects of the nano-emulsions based on essential oils from citrus peels with emphasis on their mechanisms of action and potential applications in, e.g., foods, pharmaceuticals, and cosmetics.

Preservative effect of gelatin/chitosan-based films incorporated with lemon essential oil on grass carp (Ctenopharyngodon idellus) fillets during storage

The present study investigated the effect of fish gelatin/chitosan-based (FG/CS-based) films incorporated with lemon essential oil (LEO) on grass carp fillets in terms of moisture status, total volatile basic nitrogen (TVB-N), and microbial community succession during chilled (4 °C) and iced (0 °C) storage. Low-field nuclear magnetic resonance (LF-NMR) revealed that the active films remarkably inhibited moisture transformation from being the immobilized to free water in grass carp fillets, accompanied with the reduced T22 relaxation time. Besides, magnetic resonance imaging (MRI) detected a higher density of proton in the treated fish samples, indicating that the active films could improve the water-holding capacity of fish samples. Moreover, high-throughput 16S rRNA sequencing suggested that the FG/CS-based films loaded with LEO efficiently decreased the relative abundance of the bacterial genera Shewanella and Aeromonas in grass carp fillets, with minimal accumulation of TVB-N during storage. Additionally, the low storage temperature (0 °C) could further enhance the preservative effect of the active films on the fish samples, which together prolonged their shelf-life to 18 days. Overall, the combination of the active films and iced storage could provide a promising strategy to preserve grass carp fillets.

Recent developments in nanoemulsions against spoilage in cold-stored fish: A review

Nanoemulsion-based technology is developing rapidly in the food industry, especially in the design of delivery systems for bioactive compounds. This review presents an in-depth understanding of the composition, function, antibacterial mechanism and successful application of nanoemulsions as preservative agents against fish spoilage. The results showed that the inclusion of bioactive substances in the food-grade nanoemulsions encapsulation system could improve its stability, control its release, inhibit the microbial growth and reproduction through a variety of targets. These nanoemulsions can inhibit fish spoilage via reducing microbial load and retarding the oxidation of proteins and lipids, thereby maintaining quality attributes of fish. In addition, nanoemulsions could be coupled with vacuum package for enhancing microbial destruction, retaining nutritional value and extending the shelf-life of fish. Accordingly, nanoemulsions are suggested as a promising strategy to inhibit fish spoilage.

Characterization and Determination of the Antibacterial Activity of Baccharis dracunculifolia Essential-Oil Nanoemulsions

The aim of this study was to evaluate the antibacterial activity of nanoemulsions of Baccharis dracunculifolia essential oil. The volatile compounds of the essential oil were identified using gas chromatography-mass spectrometry. The properties of the nanoemulsions (droplet size, polydispersity index, pH, and electrical conductivity) were determined. The antibacterial activities of the essential oil and its nanoemulsions were evaluated using MIC, MBC, and disk diffusion. The microorganisms used were: Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Streptococcus mutans ATCC 25175, and Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC BAA-1706, Salmonella enterica ATCC 14028, and Escherichia coli ATCC 25922). The major volatile compounds of the B. dracunculifolia essential oil were limonene (19.36%), (E)-nerolidol (12.75%), bicyclogermacrene (10.76%), and β-pinene (9.60%). The nanoemulsions had a mean droplet size between 13.14 and 56.84 nm. The nanoemulsions presented lower and statistically significant MIC values compared to the essential oil, indicating enhancement of the bacteriostatic action. The disk diffusion method showed that both the nanoemulsions and the essential oil presented inhibition zones only for Gram-positive bacteria, while there were no results against Gram-negative bacteria, indicating that B. dracunculifolia essential oil has a better antimicrobial effect on Gram-positive microorganisms.

Can droplet size influence antibacterial activity in ultrasound-prepared essential oil nanoemulsions?

Essential oil nanoemulsion may have improved antibacterial properties over pure oil and can be used for food preservation. Ultrasonic cavitation is the most common mechanism for producing nanoemulsions, and the impact of processing parameters on droplet properties needs to be elucidated. A systematic literature search was performed in four databases (Science Direct, Web of Science, Scopus and PubMed), and 987 articles were found, 16 of which were eligible for the present study. A meta-analysis was performed to qualitatively assess which process parameters (power, sonication time, essential oil, and tween 80 concentration) can influence the final droplet size and polydispersity and how droplet size is associated with antibacterial activity. We observed that power, essential oil, and tween 80 concentrations added during processing are the critical variables for forming smaller droplets. Ratios of up to 3:1 (surfactant:oil) can produce droplets smaller than 180 nm with antibacterial properties superior to pure oil or isolated compounds. The improved properties of nanoemulsions are associated with the size and chemical composition of the droplet since the proportion of the hydrophobic core (EO) and the hydrophilic outer layer (Tween 80) directly influences the antibacterial mechanism of action.

Formulation of a Stable Oil-in-Water Microemulsion of Torreya grandis cv. Merrillii Aril Essential Oil and Its Application in Loquat Fruit Preservation

Loquat is a nutrient-rich fruit with juicy and sweet pulp, but it is vulnerable to rot and deterioration without proper postharvest preservation measures. This study aimed to improve the postharvest quality of loquat by developing a microemulsion system based on an essential oil extracted from the Torreya grandis cv. Merrillii aril (TaEO), which has antimicrobial and antioxidant properties. An optimal TaEO microemulsion (TaEO-ME) was formulated, using a mixture of Tween-40 and Tween-80 as the surfactant, 1-butanol as the co-surfactant, and TaEO as the oil phase, with mass ratios of 9:1, 3:1, and 6:1, respectively. Two TaEO-ME formulations with 60% and 70% water contents were stable for 180 days at room temperature, with a mean droplet size below 12 nm and polydispersity index less than 0.24. They also exhibited higher stability and enhanced biological activities compared to free TaEO. Loquat fruit treated with TaEO-ME displayed a reduced decay index and lower membrane lipid peroxidation after 15 days of storage at 15 °C, as indicated by the lower malondialdehyde content and higher peroxidase activity. Moreover, the TaEO-ME treatment preserved the nutrient quality by maintaining the total phenolic compounds and ascorbic acid content. Our findings suggested that TaEO-ME can be used as a substitute for chemical preservatives to keep fruits fresh.

Eco-sustainable coatings based on chitosan, pectin, and lemon essential oil nanoemulsion and their effect on strawberry preservation

Films and coatings manufactured with bio-based renewable materials, such as biopolymers and essential oils, could be a sustainable and eco-friendly alternative for protecting and preserving agricultural products. In this work, we developed films and coatings from pectin and chitosan to protect strawberries (Fragaria x ananassa Duch.) from spoilage and microbial contamination. We developed three coatings containing equal amounts of glycerol and Sicilian lemon essential oil (LEO) nanoemulsion. We identified seventeen chemicals from LEO by GC-MS chromatogram, including d-limonene, α-Pinene, β-Pinene, and γ-Terpinene. The pectin and chitosan coatings were further characterized using different physicochemical, mechanical, and biological methods. The films demonstrated satisfactory results in strength and elongation at the perforation as fruit packaging. In addition, the coatings did not influence the weight and firmness of the strawberry pulps. We observed that 100 % essential oil was released in 1440 min resulting from the erosion process. Also, the oil preserved the chemical stability of the films. Antioxidant activity (AA), measured by Electron Paramagnetic Resonance (EPR), showed that the coatings loaded with 2 % LEO nanoemulsion (PC + oil) showed that almost 50 % of AA from LEO nanoemulsion was preserved. The chitosan and the pectin-chitosan coatings (PC + oil) inhibited filamentous fungi and yeast contaminations in strawberries for at least 14 days, showing a relationship between the AA and antimicrobial results.

Physicochemical properties of Kakol (Suaeda aegyptiaca) essential oil nanoemulsion and its effect on the storage quality of rainbow trout (Oncorhynchus mykiss) during cold storage

The study aims to analyze the chemical composition of Suaeda aegyptiaca essential oil (PSAE) by GC-MS, produce the nanoemulsified essential oil (NSAE) using ultrasound, and compare the antimicrobial and antioxidant activity of the PSAE and NSAE in laboratory medium and rainbow trout fish (Oncorhynchus mykiss). Geranyl-acetone (30.52%) and p-Vinylguaiacol (10.66%), and (e)-β-ionone (7.79%) were the main PSAE chemical compounds. The mean droplet size diameter, polydispersity index, and viscosity of NSAE were 179.67 nm, 0.255, and 0.96 cP, respectively. PSAE and NSAE showed a moderate antiradical potential against DPPH- and ABTS-free radicals (50 < IC50 < 250 μg mL-1). There was no significant difference between antiradical scavenging of PSAE and NSAE (p > .05). E. faecalis and K. pneumonia were the most and lowest sensitive bacteria to PSAE and NSAE, respectively. Examining different treatments on the shelf-life of minced fish showed that Kakol essential oil could improve the shelf-life of fish between 12.5% and 60% (depending on quality index). There was no significant difference between the bioactivity of PSAE and NSAE, which means that the nanoemulsion showed acceptable performance at lower essential oil concentrations.

Fabrication and Biological Activities of All-in-One Composite Nanoemulsion Based on Blumea balsamifera Oil-Tea Tree Oil

Nanoemulsion is a new multi-component drug delivery system; the selection of different oil phases can give it special physiological activity, and play the role of "medicine and pharmaceutical excipients all-in-one". In this paper, we used glycyrrhizic acid as the natural surfactant, and Blumea balsamifera oil (BB) and tea tree oil (TTO) as the mixed oil phase, to obtain a new green functional composite nanoemulsion. Using the average particle size and polydispersion index (PDI) as the evaluation criteria, the effects of the oil ratio, oil content, glycyrrhizic acid concentration, and ultrasonic time on the nanoemulsion were systematically investigated. The stability and physicochemical properties and biological activities of BB-TTO NEs prepared via the optimum formulation were characterized. The optimal prescription was BB: TTO = 1:1, 5% oil phase, 0.7% glycyrrhizic acid, and 5 min ultrasonication time. The mean particle size, PDI, and zeta potential were 160.01 nm, 0.125, and -50.94 mV, respectively. The nanoemulsion showed non-significant changes in stability after centrifugation, dilution, and 120 days storage. These nanoemulsions were found to exhibit potential antibacterial and anti-inflammatory activities. The minimal inhibitory concentration (MIC) of BB-TTO NEs against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa is 2975 μg/mL, 2975 μg/mL, and 5950 μg/mL, respectively. A lower level of inflammatory cell infiltration and proportion of fibrosis were found in the synovial tissue of AIA rats treated with BB-TTO NEs. These findings demonstrate that the BB-TTO NEs produced in this study have significant potential for usage in antibacterial and anti-inflammatory areas.

Preparation of a thermosensitive nanofibre membrane for blackberry preservation

Blackberries provide multiple health benefits. However, they deteriorate easily during harvesting, storage, and transportation (temperature-changing). Therefore, to extend their shelf-life under variable temperature conditions, a temperature-sensitive nanofibre-based material with good preservation attributes was developed, composed of polylactic acid (PLA) electrospun fibres, loaded with lemon essential oil (LEO) and covered with poly (N-isopropylacrylamide) (PNIPAAm). Compared with PLA and PLA/LEO nanofibres, PLA/LEO/PNIPAAm exhibited good mechanical properties, oxidation resistance, antibacterial ability, and controlled release of LEO. The PNIPAAm layer prevented rapid LEO release below the low critical solution temperature (32 °C). When the temperature exceeded 32 °C, the PNIPAAm layer underwent a chain-to-globule transition and accelerated LEO release (slower than PLA/LEO). The temperature-controlled release of LEO via PLA/LEO/PNIPAAm membrane prolongs its action time. Therefore, PLA/LEO/PNIPAAm effectively maintained the appearance and nutritive quality of blackberries during variable storage temperatures. Our research demonstrated that active fibre membranes have great potential applications in preserving fresh products.

Carbon dots, cellulose nanofiber, and essential oil from Torreya grandis aril added to fish scale gelatin film for tomato preservation

In this study, carbon dots (CDs), cellulose nanofibers (CNF) and essential oil nanoemulsion (EON) were extracted from the aril waste of Torreya grandis following nuts production. These three nanomaterials were formulated for the preparation of a composite film to be employed for postharvest tomato storage. Visual, microscopical and physicochemical properties of the prepared nanocomposite films were analyzed at different levels of CDs and CNF for optimization purposes. The UV absorption and antioxidant capacity of gelatin film with 10 % CDs (G/10CD) were enhanced compared with gelatin (G) film, concurrent with a reduction in water barrier capacity, water contact angle (WCA) and tensile strength (TS). Compared with G/10CD film, the WCA of gelatin film after incorporation of 10 % CDs and 3 % CNF (G/10CD/3CNF) was significantly increased by 14.5°at 55 s. In contrast, TS increased by 1.26 MPa, as well as the significant enhancement in water barrier capacity. The above composite film mixed with NEO (G/10CD/3CNF/EON) exerted further antimicrobial effects against Escherichia coli. G/10CD/3CNF/EON coating effectively extended tomato shift life compared with the control group. Therefore, this new eco-friendly film presents several advantages of biodegradability, sustainability as well as multifunctional properties posing it as potential packaging material for food applications.

Essential oils and essential oil compounds in animal production as antimicrobials and anthelmintics: an updated review

Several countries have shown an increased prevalence of drug resistance in animal production due to the indiscriminate use of antibiotics and antiparasitics in human and veterinary medicine. This article aims to review existing methods using naturally occurring essential oils (EOs) and their isolated compounds (EOCs) as alternatives to antimicrobials and antiparasitic compounds in animal production and, consequently, to avoid resistance. The most-reported mechanism of action of EOs and EOCs was cell membrane damage, which leads to the leakage of cytoplasmic content, increased membrane permeability, inhibition of metabolic and genetic pathways, morphologic changes, antibiofilm effects, and damage to the genetic material of infections. In parasites, anticoccidial effects, reduced motility, growth inhibition, and morphologic changes have been reported. Although these compounds regularly show a similar effect to those promoted by traditional drugs, the elucidation of their mechanisms of action is still scarce. The use of EOs and EOCs can also positively influence crucial parameters in animal production, such as body weight gain, feed conversion rate, and cholesterol reduction, which also positively impact meat quality. The application of EOs and EOCs is enhanced by their association with other natural compounds or even by the association with synthetic chemicals, which has been found to cause synergism in their antimicrobial effect. By reducing the effective therapeutical/prophylactic dose, the chances of off-flavors – the most common issue in EO and EOC application – is greatly mitigated. However, there is very little work on the combination of EOs and EOCs in large in vivo studies. In addition, research must apply the correct methodology to properly understand the observed effects; for example, the use of only high concentrations may mask potential results obtained at lower dosages. Such corrections will also allow the elucidation of finer mechanisms and promote better biotechnologic use of EOs and EOCs. This manuscript presents several information gaps to be filled before the use of EOs and EOCs are fully applicable in animal production.

Antioxidant, Antibacterial and Antibiofilm Activity of Nanoemulsion-Based Natural Compound Delivery Systems Compared with Non-Nanoemulsified Versions

This study aimed to develop nanoemulsions with a focus on improving the bioactivity of oregano essential oil (OEO), carvacrol and thymol for possible food applications. Nanoemulsions were prepared with acoustic cavitation using ultrasound. The nanodroplets had average diameters of 54.47, 81.66 and 84.07 nm for OEO, thymol and carvacrol, respectively. The main compound in OEO was carvacrol (74%), and the concentration in the nanoemulsions was 9.46 mg/mL for OEO and the isolated compounds. The effects of droplet size reduction on antioxidant, antibacterial and antibiofilm activity were evaluated. Regarding antioxidant activity, the nanoemulsions performed better at the same concentration, with inhibitions >45% of the DPPH radical and significant differences compared with their non-nanoemulsified versions (p < 0.05). The nanoemulsions' minimum inhibitory concentration (MIC) and non-nanoemulsified compounds were evaluated against foodborne pathogens with inhibition ranges between 0.147 and 2.36 mg/mL. All evaluated pathogens were more sensitive to nanoemulsions, with reductions of up to four times in MIC compared with non-nanoemulsified versions. E. coli and S. Enteritidis were the most sensitive bacteria to the carvacrol nanoemulsion with MICs of 0.147 mg/mL. Concerning antibiofilm activity, nanoemulsions at concentrations up to four times lower than non-nanoemulsified versions showed inhibition of bacterial adhesion >67.2% and removal of adhered cells >57.7%. Overall, the observed effects indicate that droplet size reduction improved the bioactivity of OEO, carvacrol and thymol, suggesting that nanoemulsion-based delivery systems for natural compounds may be alternatives for food applications compared with free natural compounds.

Disease alleviating effects following prophylactic lemon and coriander essential oil treatment in mice with acute campylobacteriosis

Introduction

Given the worldwide increasing prevalence of human Campylobacter jejuni infections and the emergence of multi-drug resistant enteropathogenic strains, antibiotic-independent approaches applying non-toxic natural compounds for the treatment and prophylaxis of campylobacteriosis appear utmost desirable. In our placebo-controlled intervention study, we surveyed potential disease-alleviating including anti-pathogenic and immune-modulatory effects upon prophylactic oral application of lemon-essential oil (LEM-EO) and coriander-essential oil (COR-EO) in acute experimental campylobacteriosis.

Methods

Therefore, secondary abiotic IL-10−/− mice were orally challenged with either LEM-EO or COR-EO starting seven days prior to peroral C. jejuni infection.

Results and discussion

Six days post-infection, slightly lower pathogen loads were assessed in the colon of mice from the LEM-EO as opposed to the COR-EO cohort if compared to placebo counterparts. Prophylactic application of both EOs improved the clinical outcome of acute campylobacteriosis which was paralleled by less distinct pathogen-induced colonic epithelial cell apoptosis. Moreover, mice subjected to LEM-EO and COR-EO prophylaxis displayed lower colonic numbers of macrophages/monocytes and of T lymphocytes, respectively, whereas in both verum groups, basal IL-6 and IFN-γ concentrations were measured in mesenteric lymph nodes on day 6 post-infection. The oral challenge with either EOs resulted in diminished secretion of distinct pro-inflammatory mediators in the kidney as well as serum samples derived from the infected mice. In conclusion, the results from our preclinical in vivo study provide evidence that LEM-EO and COR-EO constitute promising prophylactic measures to prevent severe campylobacteriosis which may help to reduce the risk for development of post-infectious sequelae in C. jejuni infected individuals.

Betaine and nano-emulsified vegetable oil supplementation for improving carcass and meat quality characteristics of broiler chickens under heat stress conditions

Introduction

This research aimed to examine the effects of water-added betaine (BET) and/or nano-emulsified vegetable oil (MAGO) on carcass and meat quality characteristics of broilers raised under thermoneutral (TN) and heat stress (HS) conditions.

Methods

On day 21, 640 birds (Ross 308) were randomly assigned to one of two thermal conditions (thermoneutral 22 ± 1°C and heat stress 32 ± 1°C) each containing four treatment groups: Control, BET, MAGO, and a mixture of both (BETMAGO) in a 2 × 4 factorial arrangement (eight groups). Each group has eight replicates, with ten birds each. The birds' carcass and meat quality characteristics were evaluated at 35 days.

Results and discussion

The dressing percentage, breast, leg, wing, heart, initial pH, color change, cooking loss (CL), water-holding capacity (WHC), shear force (SF), and texture profile with exception of springiness significantly affected by the treatments. The results showed that HS had negative effects on carcass weight and relative weights of the breast, spleen, and heart. Moreover, HS increased dressing percentage, wing, initial pH, final core temperature, initial lightness, WHC, and hardness. Significant differences in interactions between treatments and temperature were observed in the spleen, WHC, and SF.

Conclusion

Water supplemented with BET effectively improved carcass dressing percentage, breast weight, and meat quality in terms of water-holding capacity and tenderness under HS conditions. More studies on the use of BET and/or MAGO at different levels were recommended.

Meta-Analysis of In Vitro Antimicrobial Capacity of Extracts and Essential Oils of Syzygium aromaticum, Citrus L. and Origanum L.: Contrasting the Results of Different Antimicrobial Susceptibility Methods

Diffusion methods, including agar disk-diffusion and agar well-diffusion, as well as dilution methods such as broth and agar dilution, are frequently employed to evaluate the antimicrobial capacity of extracts and essential oils (EOs) derived from Origanum L., Syzygium aromaticum, and Citrus L. The results are reported as inhibition diameters (IDs) and minimum inhibitory concentrations (MICs), respectively. In order to investigate potential sources of variability in antimicrobial susceptibility testing results and to assess whether a correlation exists between ID and MIC measurements, meta-analytical regression models were built using in vitro data obtained through a systematic literature search. The pooled ID models revealed varied bacterial susceptibilities to the extracts and in some cases, the plant species and methodology utilised impacted the measurements obtained (p < 0.05). Lemon and orange extracts were found to be most effective against E. coli (24.4 ± 1.21 and 16.5 ± 0.84 mm, respectively), while oregano extracts exhibited the highest level of effectiveness against B. cereus (22.3 ± 1.73 mm). Clove extracts were observed to be most effective against B. cereus and demonstrated the general trend that the well-diffusion method tends to produce higher ID (20.5 ± 1.36 mm) than the disk-diffusion method (16.3 ± 1.40 mm). Although the plant species had an impact on MIC, there is no evidence to suggest that the methodology employed had an effect on MIC (p > 0.05). The ID–MIC model revealed an inverse correlation (R2 = 47.7%) and highlighted the fact that the extract dose highly modulated the relationship (p < 0.0001). The findings of this study encourage the use of extracts and EOs derived from Origanum, Syzygium aromaticum, and Citrus to prevent bacterial growth. Additionally, this study underscores several variables that can impact ID and MIC measurements and expose the correlation between the two types of results.

Nanoemulsion-based approach to preserve muscle food: A review with current knowledge

Muscle foods are regarded as nutritionally dense foods while they are prone to spoilage by action of microorganism and oxidation. Recently, the consumer's preference is mostly toward minimally processed foods as well as preserved with natural preservatives. However, natural extract directly to the food matrix has several drawbacks. Hence development and applications of nanoemulsion has gained importance for the preservation of muscle foods to meet consumer requirements with enhanced food safety. Nanoemulsion utilizes natural extracts at much lower concentration with higher preservative abilities over original components. Nanoemulsions offer protection to the active component from degradation and ensure longer bioavailability. Novel techniques used for formulation of nanoemulsion provide stability to the emulsion with desirable qualities to improve their impacts. The application of nanoemulsion is known to enhance the preservative action of nanoemulsions by improving the microbial safety and oxidative stability in nanoform. This review provides recent updates on different methods used for formulation of nanoemulsions from different sources. Besides, successful application of nanoemulsion derived using natural agents for muscle food preservation and shelf life extension are reviewed. Thus, the application of nanoemulsion to extend shelf life and maintain quality is suggested for muscle foods.

Effects of citrus essential oils on the oxidative stability of microencapsulated fish oil by spray-drying

The effects of citrus essential oils (orange, lemon, mandarin, and grapefruit) on the oxidative stability of microencapsulated fish oil by spray-drying were evaluated. The encapsulation efficiency of microcapsules was in the range of 42.25 and 62.43%. Twelve active substances were determined as major volatile components of citrus essential oils. The highest phenolic content was obtained from grapefruit essential oil (44.32 mg GAE/g). Lower values of thiobarbituric acid reactive substances (TBARs) were obtained for microencapsulated fish oils with essential oils compared to control. At the end of storage, the highest peroxide value (PV) was observed in the control group (25.30 meq O₂/kg oil) while the lowest value was in the lemon (13.40 meq O₂/kg oil) and orange group (13.91 meq O₂/kg oil). The results of this study showed that citrus essential oils can be used to improve the oxidative stability of fish oil microcapsules.

Functional insights to the development of bioactive material for combating bacterial infections

The emergence of antibiotic-resistant "superbugs" poses a serious threat to human health. Nanomaterials and cationic polymers have shown unprecedented advantages as effective antimicrobial therapies due to their flexibility and ability to interact with biological macromolecules. They can incorporate a variety of antimicrobial substances, achieving multifunctional effects without easily developing drug resistance. Herein, this article discusses recent advances in cationic polymers and nano-antibacterial materials, including material options, fabrication techniques, structural characteristics, and activity performance, with a focus on their fundamental active elements.

Effects of adding nano-emulsified plant oil and probiotics to drinking water during different periods besides sex on processing characteristics, physicochemical properties, and meat quality traits of broiler chickens

Introduction

High-quality meat is one of the consumer demands. Therefore, several studies have concluded that supplementing broilers with natural additives can improve meat quality. This study was carried out to evaluate the effects of nano-emulsified plant oil (Magic oil^®) and probiotic (Albovit^®) as water additives (at the rate of 1 ml/L and 0.1 g/L, respectively) during different growing periods on processing characteristics, physicochemical properties, and meat quality traits of broilers chickens.

Methods

A total number of 432-day-old Ross broiler chicks were randomly assigned to one of six treatment groups according to the growing periods in which magic oil and probiotics were added to drinking water, each with nine replicates and eight birds per replicate (4♂ and 4♀). On day 35, birds' processing characteristics, physicochemical properties, and meat quality traits were examined.

Results and discussion

The results showed that treatments had a significant (P < 0.001) impact on cooking loss, cohesiveness, and chewiness. The male broiler chickens had higher (P ≤ 0.05) initial lightness, initial whiteness index, water holding capacity, shear force, live weight, hot and chilled carcass weights, as well as lower gizzard and neck percentages than females. The interactions between treatments and sex showed a significant (P < 0.001) impact on cooking loss, shear force, hardness, springiness, and chewiness. In conclusion, supplementing male broiler chickens with Magic oil and probiotic, particularly from 0-30 days of age had favorable meat chewiness as a result of lower cohesiveness and hardness higher springiness, and the most convenient cooking loss value. Magic oil and probiotic, especially in males, is advisable to be supplemented in water of growing broilers chicken programs from 0 to 30 days of age. Moreover, further studies under commercial conditions are recommended to locate the most favorable combination of Magic oil/probiotic supplements for the best processing characteristics and meat quality attributes outcomes.

Comparison of antibacterial and antioxidant potentials of pure and nanoemulsified Nepeta pogonosperma essential oil

The current study aimed to investigate the antiradical and antibacterial potential of pure and its nanoemulsified (NNE) Nepeta pogonosperma essential oil (PNE). Antimicrobial activity of the essential oil against two Gram-positive (E. faecalis and B. cereus) and two Gram-negative (M. catarrhalis and K. pneumonia) food-related pathogens during 60-day storage was investigated based on disc diffusion, minimum inhibition concentration (MIC), and minimum bactericidal concentration (MBC). The chemical compounds of Nepeta essential oil were estimated by GC/MS. The physical properties of the nanoemulsion including polydispersity index (PDI), mean particle diameter, and viscosity were also determined. 4aα,7α,7aβ-Nepetalactone (46.31%), 1,8-cineole (23.13%), and (Z)-α-bisabolene (4.01%) were the main compounds of this essential oil. The Nepeta nanoemulsion had a mean droplet diameter of 254.07 nm, PDI of 0.281, and viscosity of 0.887 cP. NNE had stability for up to 60 days. The PNE showed a higher IC₅₀ value than NNE (p < .05). During storage, the antiradical performance of both PNE and NNE was decreased (p < .05). However, emulsification was successful to control this decreasing trend. E. faecalis was the most susceptible bacteria to PNE and NNE, while the lowest inhibition zone was obtained for K. pneumoniae. At the first time, the antibacterial effect of PNE was more than NNE. However, over time nanoemulsion became more successful in maintaining its antibacterial effect. Overall, the incorporation of Nepeta pogonosperma essential oil into a nanoemulsion system can be a promising system to maintain the bioactivity of the essential oil for a longer time.

Metabolomics insights into the potential of encapsulated essential oils as multifunctional food additives

Growing consumer concern about foodborne disease outbreaks and health risks associated with chemical additives has propelled the usage of essential oils (EOs) as novel food additives, but are limited by instability. In this regard, a series of EOs nano/micro-capsules have been widely used to enhance their stability and improve food quality. However, classical food quality assessment methods are insufficient to fully characterize the effects of encapsulated EOs on food properties, including physical, biochemical, organoleptic, and microbial changes. Recently, the rapid development of high-throughput sequencing is accelerating the application of metabolomics in food safety and quality analysis. This review seeks to present the most recent achievements in the application of non-targeted metabolomics to identify and quantify the overall metabolite profile associated with food quality, which can guide the development of emerging food preservation technologies. The scientific findings confirm that metabolomics opens up exciting prospects for biomarker screening in food preservation and contributes to an in-depth understanding of the mechanisms of action (MoA) of EOs. Future research should focus on constructing food quality assessment criteria based on multi-omics technologies, which will drive the standardization and commercialization of EOs for food industry applications.

Antimicrobial activities of emulsion-based edible solutions incorporating lemon essential oil and sodium caseinate against some food-borne bacteria

The antimicrobial properties of two different emulsion formulations contained lemon essential oil (coarse emulsion; CE and nanoemulsion; NE) and emulsions based edible solutions incorporated with lemon essential oil and sodium caseinate (coarse emulsion based solution; CESC and nanoemulsion based solution; NESC) on food-related microorganisms (Photobacterium damselae, Pseudomonas luteola, Salmonella Paratyphi A NCTC13, and Listeria monocytogenes ATCC19112) were investigated. The chemical compositions of lemon essential oils were identified by GC-MS. Physical parameter of different formulations was also analyzed at different time intervals. The antimicrobial properties of solutions were determined by using well diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration, and time-kill assay. The major identified component in lemon essential oil was D limonene (38.38%). NE showed a stronger antimicrobial effect against S. Paratyphi A and L. monocytogenes with 36.50 and 38.75 mm diameter zone compared to all other formulations. Listeria monocytogenes had the highest sensitivity towards NE and NESC formulations with 3.12 mg/ml MIC values in comparison to other two formulations. The nanoemulsion and nanoemulsion based coating solution were more effective than other formulations in killing bacterial cell within a short period time.

The Use of Biopolymers as a Natural Matrix for Incorporation of Essential Oils of Medicinal Plants

The benefits of using biopolymers for the development of films and coatings are well known. The enrichment of these material properties through various natural additions has led to their applicability in various fields. Essential oils, which are well-known for their beneficial properties, are widely used as encapsulating agents in films based on biopolymers. In this study, we developed biopolymer-based films and tested their properties following the addition of 7.5% and 15% (w/v) essential oils of lemon, orange, grapefruit, cinnamon, clove, chamomile, ginger, eucalyptus or mint. The samples were tested immediately after development and after one year of storage in order to examine possible long-term property changes. All films showed reductions in mass, thickness and microstructure, as well as mechanical properties. The most considerable variations in physical properties were observed in the 7.5% lemon oil sample and the 15% grapefruit oil sample, with the largest reductions in mass (23.13%), thickness (from 109.67 µm to 81.67 µm) and density (from 0.75 g/cm3 to 0.43 g/cm3). However, the microstructure of the sample was considerably improved. Although the addition of lemon essential oil prevented the reduction in mass during the storage period, it favored the degradation of the microstructure and the loss of elasticity (from 16.7% to 1.51% for the sample with 7.5% lemon EO and from 18.28% to 1.91% for the sample with 15% lemon EO). Although the addition of essential oils of mint and ginger resulted in films with a more homogeneous microstructure, the increase in concentration favored the appearance of pores and modifications of color parameters. With the exception of films with added orange, cinnamon and clove EOs, the antioxidant capacity of the films decreased during storage. The most obvious variations were identified in the samples with lemon, mint and clove EOs. The most unstable samples were those with added ginger (95.01%), lemon (92%) and mint (90.22%).

Research Progress on Nutritional Value, Preservation and Processing of Fish-A Review

The global population has rapidly expanded in the last few decades and is continuing to increase at a rapid pace. To meet this growing food demand fish is considered a balanced food source due to their high nutritious value and low cost. Fish are rich in well-balanced nutrients, a good source of polyunsaturated fatty acids and impose various health benefits. Furthermore, the most commonly used preservation technologies including cooling, freezing, super-chilling and chemical preservatives are discussed, which could prolong the shelf life. Non-thermal technologies such as pulsed electric field (PEF), fluorescence spectroscopy, hyperspectral imaging technique (HSI) and high-pressure processing (HPP) are used over thermal techniques in marine food industries for processing of most economical fish products in such a way as to meet consumer demands with minimal quality damage. Many by-products are produced as a result of processing techniques, which have caused serious environmental pollution. Therefore, highly advanced technologies to utilize these by-products for high-value-added product preparation for various applications are required. This review provides updated information on the nutritional value of fish, focusing on their preservation technologies to inhibit spoilage, improve shelf life, retard microbial and oxidative degradation while extending the new applications of non-thermal technologies, as well as reconsidering the values of by-products to obtain bioactive compounds that can be used as functional ingredients in pharmaceutical, cosmetics and food processing industries.

Garlic essential oil in water nanoemulsion prepared by high-power ultrasound: Properties, stability and its antibacterial mechanism against MRSA isolated from pork

Food-borne methicillin-resistance Staphylococcus aureus (MRSA) has caused significant health threats and economic loss in livestock and poultry products. Garlic essential oil (GEO) is an effective antibacterial agent but presents strong instability and hydrophobicity. In this study, GEO in water nanoemulsion (GEON) with good stability was produced by emulsification technique of high-power ultrasound. Its antibacterial activity and underlying mechanism against MRSA isolated from retailed pork were investigated. Results showed that ultrasonic treatment significantly reduced the particle size of GENO from 820.3 to 215.0 nm as time increased from 0 to 10 min. Comparatively, GEON of 10 min ultrasound was more stable than other GEONs (0, 1, 5 min) during 30 d storage. It also displayed good thermal stability and relatively good ion stability (NaCl, MgCl₂, and glucose). Antibacterial analysis showed that GEON (10 min) exhibited the best anti-MRSA activity among all GEONs, and the minimum inhibitory concentration of GEO in this nanoemulsion was 0.125 % (1.25 mg/mL). Treatment of GEON (10 min) significantly suppressed the cell proliferation of MRSA, which was mainly achieved by damaging the cell membrane as evidenced by membrane depolarization and considerable leakage of intracellular nucleic acids and protein. Laser scanning confocal microscope and scanning electron microscopy showed that treatment of GEON (10 min) significantly altered the membrane integrity and severely damaged the cellular membrane and structure. The present work illustrated that GEON produced by ultrasonic emulsification is a promising alternative to inhibit the contamination and spread of MRSA in livestock and poultry products.

Inhibitory Effect of Sodium Alginate Nanoemulsion Coating Containing Myrtle Essential Oil (Myrtus communis L.) on Listeria monocytogenes in Kasar Cheese

The present study aimed to characterize the physical properties of nanoemulsion-based sodium alginate edible coatings containing myrtle (Myrtus communis L.) essential oil and to determine its inhibitory effects on Listeria monocytogenes in fresh Kasar cheese during the 24-day storage at 4 °C. The GC-MS analysis showed that the main components of myrtle essential oil were 1,8-cineol (38.64%), α-pinene (30.19%), d-limonene (7.51%), and α-ocimene (6.57%). Myrtle essential oil showed an inhibitory effect on all tested L. monocytogenes strains and this effect significantly increased after ultrasonication. Minimum inhibitory and minimum bactericidal concentrations of myrtle essential oil nanoemulsion were found to be 4.00-4.67 mg/mL and 5.00-7.33 mg/mL, respectively. The antibacterial activity of myrtle essential oil nanoemulsion against L. monocytogenes was confirmed by the membrane integrity and FESEM analyses. Nanoemulsion coatings containing myrtle essential oil showed antibacterial activity against L. monocytogenes with no adverse effects on the physicochemical properties of cheese samples. Nanoemulsion coatings containing 1.0% and 2.0% myrtle essential oil reduced the L. monocytogenes population in cheese during the storage by 0.42 and 0.88 log cfu/g, respectively. These results revealed that nanoemulsion-based alginate edible coatings containing myrtle essential oil have the potential to be used as a natural food preservative.

Cinnamon essential oil and its emulsion as efficient antibiofilm agents to combat Acinetobacter baumannii

Acinetobacter baumannii is an emerging nosocomial pathogen resistant to a wide spectrum of antibiotics, with great potential to form a biofilm, which further aggravates treatment of infections caused by it. Therefore, searching for new potent agents that are efficient against A. baumannii seems to be a necessity. One of them, which has already been proven to possess a wide spectrum of biological activities, including antimicrobial effect, is cinnamon essential oil. Still, further increase of antibacterial efficacy and improvement of bioavailability of cinnamon oil is possible by emulsification process. The aim of this study was comparative analysis of cinnamon essential oil and its emulsion against biofilm forming A. baumannii clinical isolates. Furthermore, the investigation of toxicological aspects of possible applications of essential oil and emulsion was done as well. Gas chromatography–mass spectrometry of essential oil indicated trans-cinnamaldehyde as the most abundant component. The cinnamon emulsion was synthesized from cinnamon essential oil by combining modified low- and high- energy methods. Synthesized emulsion was characterized with Fourier-transform infrared spectroscopy and photon correlation spectroscopy. Both substances exhibited significant antibacterial (minimal inhibitory concentrations in the range 0.125–0.5 mg/ml) and antibiofilm effects (inhibitions of formation and reduction of pre-formed biofilm were 47–81 and 30–62%, respectively). Compared to essential oil, the efficacy of emulsion was even stronger considering the small share of pure oil (20%) in the emulsion. The result of biofilm eradication assay was confirmed by scanning electron microscopy. Even though the cytotoxicity was high especially for the emulsion, genotoxicity was not determined. In conclusion, strong antibacterial/antibiofilm effect against A. baumannii of the cinnamon essential oil and the fact that emulsification even potentiated the activity, seems to be of great significance. Observed cytotoxicity implicated that further analysis is needed in order to clearly determine active principles being responsible for obtained antibacterial/antibiofilm and cytotoxic properties.

Preparation, Characterization and Biological Activities of an Oil-in-Water Nanoemulsion from Fish By-Products and Lemon Oil by Ultrasonication Method

Fish by-product oil and lemon oil have potential applications as active ingredients in many industries, including cosmetics, pharmaceuticals and food. However, the physicochemical properties, especially the poor stability, compromised the usage. Generally, nanoemulsions were used as an approach to stabilize the oils. This study employed an ultrasonication method to form oil-in-water nanoemulsion of lemon and fish by-product oils (NE-FLO). The formulation is produced at a fixed amount of 2 wt% fish by-product oil, 8 wt% lemon oil, 10 wt% surfactant, 27.7 wt% co-surfactants and 42 min of ultrasonication time. The size, polydispersity index (PDI) and zeta potential obtained were 44.40 nm, 0.077, and −5.02 mV, respectively. The biological properties, including antioxidant, antibacterial, cell cytotoxicity, and anti-inflammatory, showed outstanding performance. The antioxidant activity is comparable without any significant difference with ascorbic acid as standard and is superior to pure lemon oil. NE-FLO successfully inhibits seven Gram-positive and seven Gram-negative bacterial strains. NE-FLO’s anti-inflammatory activity is 99.72%, comparable to nordihydroguaiaretic acid (NDGA) as the standard. At a high concentration of 10,000 µg·mL⁻¹, NE-FLO is non-toxic to normal skin cells. These findings demonstrate that the NE-FLO produced in this study has significant potential for usage in various industries.

Deciphering the virulent Vibrio harveyi causing spoilage in muscle of aquatic crustacean Litopenaeus vannamei

The muscle of aquatic crustaceans is perishable and susceptible to environmental contamination. Vibrio harveyi is a widely occurring pathogen in aquatic animals. Here, bath treatment with a virulent V. harveyi strain (which was added directly in the rearing water to imitate environmental contamination) isolated from the muscle of the whiteleg shrimp, Litopenaeus vannamei, caused the muscle of Li. vannamei to display a whitish-opaque appearance due to microscopic changes including muscle lysis, muscle fiber damage and microbial colonization. When administered orally by incorporating this isolate in feed (which is an imitation of infection via natural route), rather than direct invasion followed by colonization in the muscle, this isolate indirectly stimulated severe muscle necrosis in Li. vannamei via steering the enrichment of two important (human) pathogens, V. cholerae and V. vulnificus, and one environmental bacterium Pseudomonas oleovorans, based on the meta-taxonomic analyses. In addition to the scientifically proven viral diseases, our research proved that bacterial agents are also capable of causing muscle spoilage in crustaceans via changing the microbial composition, and that the crustaceans might be exploited as the wide-spectrum sensitive bio-detector to indicate the extent of microbial contamination.

Tracking spoilage bacteria in the tuna microbiome

Like other seafood products, tuna is highly perishable and sensitive to microbial spoilage. Its consumption, whether fresh or canned, can lead to severe food poisoning due to the activity of specific microorganisms, including histamine-producing bacteria. Yet, many grey areas persist regarding their ecology, conditions of emergence, and proliferation in fish. In this study, we used 16S rRNA barcoding to investigate postmortem changes in the bacteriome of fresh and brine-frozen yellowfin tuna (Thunnus albacares), until late stages of decomposition (i.e. 120 h). The results revealed that despite standard refrigeration storage conditions (i.e. 4°C), a diverse and complex spoilage bacteriome developed in the gut and liver. The relative abundance of spoilage bacterial taxa increased rapidly in both organs, representing 82% of the bacterial communities in fresh yellowfin tuna, and less than 30% in brine-frozen tuna. Photobacterium was identified as one of the dominant bacterial genera, and its temporal dynamics were positively correlated with histamine concentration in both gut and liver samples, which ultimately exceeded the recommended sanitary threshold of 50 ppm in edible parts of tuna. The results from this study show that the sanitary risks associated with the consumption of this widely eaten fish are strongly influenced by postcapture storage conditions.

Tea Tree Oil Nanoemulsion Potentiates Antibiotics against Multidrug-Resistant Escherichia coli

Extensive efforts are underway to overcome the rising prevalence of antibiotic resistance. Combination therapy may be a potential method to treat multidrug-resistant (MDR) bacterial infections. In this study, tea tree essential oil (TTO) nanoemulsion (nanoTTO) was used in combination with antibiotics to kill microbes. Results showed that nanoTTO enhanced the activities of multiple antibiotics against MDR Escherichia coli (E. coli), and its antimicrobial activity was not changed against bacteria that were cultured in the presence of nanoTTO for 30 passages. Further studies to visualize and quantify intracellular antibiotics concentrations identified that nanoTTO increased the drug accumulation in MDR E. coli by disrupting outer and inner membranes and inhibiting the AcrAB-TolC efflux pump involved in membrane permeability. In addition, nanoTTO was effective in enhancing antibiotic efficacy in the Galleria mellonella infection model and mouse peritonitis model, suggesting a potential strategy against MDR bacterial infections.

Sequence-Selected C13-Dipeptide Self-Assembled Hydrogels for Encapsulation of Lemon Essential Oil with Antibacterial Activity

Supramolecular self-assembling peptide hydrogels are attracting attention. The switching of even one amino acid may lead to differences in structure and functions of peptide hydrogels. Herein, we investigate the effect of substitution of a single amino acid residue on the gelation properties of C₁₃-dipeptide hydrogels. We show that four C₁₃-R₁Y (C₁₃-VY, C₁₃-FY, C₁₃-WY, and C₁₃-YY) can form hydrogels with drastically tunable rigidity (the G' values were 5.74, 0.16, 27.74, and 67.90 KPa, respectively). Moreover, C₁₃-WY and C₁₃-YY hydrogels with high stability and excellent mechanical properties formed β-sheet nanofiber cross-linked networks. Furthermore, we applied four hydrogels into encapsulation of lemon essential oil (LEO). The peptide hydrogels had a high encapsulation rate and slowly released the LEO. Importantly, the LEO-loaded hydrogels showed enhanced antibacterial activity than free LEO. Our results clearly demonstrate the significance of side-chain interactions in determining hydrogel properties and their potential application in encapsulation for nutrition agents and hydrophobic drugs.

The impact of aromatic plant-derived bioactive compounds on seafood quality and safety

Plant-derived bioactive compounds have been extensively studied and used within food industry for the last few decades. Those compounds have been used to extend the shelf-life and improve physico-chemical and sensory properties on food products. They have also been used as nutraceuticals due to broad range of potential health-promoting properties. Unlike the synthetic additives, the natural plant-derived compounds are more acceptable and often regarded as safer by the consumers. This chapter summarizes the extraction methods and sources of those plant-derived bioactives as well as recent findings in relation to their health-promoting properties, including cardio-protective, anti-diabetic, anti-inflammatory, anti-carcinogenic, immuno-modulatory and neuro-protective properties. In addition, the impact of applying those plant-derived compounds on seafood products is also investigated by reviewing the recent studies on their use as anti-microbial, anti-oxidant, coloring and flavoring agents as well as freshness indicators. Moreover, the current limitations of the use of plant-derived bioactive compounds as well as future prospects are discussed. The discoveries show high potential of those compounds and the possibility to apply on many different seafood. The compounds can be applied as individual while more and more studies are showing synergetic effect when those compounds are used in combination providing new important research possibilities.

Protective Effect of Lemon Essential Oil and Its Major Active Component, D-Limonene, on Intestinal Injury and Inflammation of E. coli-Challenged Mice

Inflammatory diseases are a major threat to public health. Natural plant essential oils (EOs) possess anti-inflammatory and anti-oxidative activities. The objective of this study was to investigate the anti-inflammatory effect and mode of action of lemon essential oil (LEO), and its main active component, d-limonene, with different doses on intestinal inflammation of mice. Sixty-four 5-week-old male balb/c mice weighing 22.0 ± 1.5 g were randomly assigned into one of 8 treatments (n = 8/treatment), including normal saline group (NS), Escherichia coli (E. coli) group, and either LEO and d-limonene essential oil (DEO) group supplemented at 300, 600, and 1,200 mg/kg of BW, respectively. After the pre-feeding period, the mice were fasted for 12 h, the mice in the NS group and the E. coli group were gavaged with normal saline, and the mice in the LEO group and DEO group were gavaged with respective dose of EOs for 1 week. One hour after the end of gavage on the 7th day, except that the mice in the normal saline group were intraperitoneally injected with normal saline, the mice in the other groups were intraperitoneally injected with the same concentration of E. coli (108 cfu/ml, 0.15 ml per mouse). The antioxidant indexes were measured including superoxide dismutase (SOD), malondialdehyde (MDA), and myeloperoxidase (MPO) in plasma obtained by taking blood from mouse eyeballs. The inflammatory indexes were measured including interleukin-6 (IL-6), interleukin-1β (IL-1β), and tumor necrosis factor alpha (TNF-α) in plasma. The tight junction protein indicators were tested include zona occludens 1 protein (ZO-1), occludin and claudin in mouse duodenum. We found that all of the above indexes for E. coli group were different (P&lt; 0.05) with the NS group. The interaction of EO and dose (E × D) were significant (P &lt; 0.01) for all of the indexes. In addition, LEO at 300 mg/kg BW and DEO at 600 mg/kg BW had better antioxidant and anti-inflammation activity on the infected mice, which reduced (P &lt; 0.05) the plasma concentrations of MDA, MPO, TNF-α, IL-1β, and IL-6, but increased (P &lt; 0.01) the concentrations of SOD. Hematoxylin-eosin (H&amp;E) staining of duodenum observation showed that LEO and DEO reduced inflammatory cell infiltration and maintain the orderly arrangement of epithelial cells. Moreover, supplementation of LEO at 600 mg/kg and DEO at 300 mg/kg BW alleviated (P &lt; 0.05) intestinal barrier injury for increasing the relative expression of ZO-1, occludin and claudin mRNA in mice duodenum. These results showed that the pre-treatment with LEO and DEO had protection of intestinal tissue and inflammation in E. coli infected mice. Both LEO and DEO exhibited activity of antioxidant, anti-inflammatory and alleviating intestinal injury, whereas, compared with DEO, LEO can be active at a lower dosage. Furthermore, as the main active component of LEO, the d-limonene appeared to play not only the major role, but also the joint action with other active components of LEO.

Protective Effects of Grapefruit Essential Oil against Staphylococcus Aureus-Induced Inflammation and Cell Damage in Human Epidermal Keratinocytes

Staphylococcus aureus (S. aureus) is a common skin pathogenic bacterium, over-colonization can induce skin infections, while its metabolites can also produce irritation to the skin, often accompanied by eczema dermatitis, specific dermatitis and other skin diseases. Grapefruit essential oil is extracted from the fruit of grapefruit (Citrus maxima (Burm) Merr.), a citrus plant that is rich in flavonoids, phenolic acids and high flavanones. Due to its good odor and biological activity such as anti-inflammatory, antibacterial, etc., grapefruit essential oil has been widely used as an additive in food. To evaluate the potential application of grapefruit essential oil as raw materials in cosmetics products and health foods, we developed a cell damage model of skin inflammation stimulated by S. aureus metabolites. Compared to that of lime essential oil, an internal control, we found that grapefruit essential oil could significantly promote HaCaT cells proliferation, reduce reactive oxygen species (ROS) production induced by S. aureus metabolites, inhibit the upregulated expression of IL-1 and COX-2. In the 3D epidermal model, grapefruit essential oil could recover the decreased LOR and FLG contents caused by S. aureus metabolites. These results demonstrated pharmacological evidence for the anti-inflammatory effect of grapefruit essential oil, suggesting a potential application of grapefruit essential oil as cosmetic raw materials for repair and alleviating of skin inflammation caused by S. aureus.

Recent developments in industrial applications of nanoemulsions

Nanotechnology is being utilized in various industries to increase the quality, safety, shelf-life, and functional performance of commercial products. Nanoemulsions are thermodynamically unstable colloidal dispersions that consist of at least two immiscible liquids (typically oil and water), as well as various stabilizers (including emulsifiers, texture modifiers, ripening inhibitors, and weighting agents). They have unique properties that make them particularly suitable for some applications, including their small droplet size, high surface area, good physical stability, rapid digestibility, and high bioavailability. This article reviews recent developments in the formulation, fabrication, functional performance, and gastrointestinal fate of nanoemulsions suitable for use in the pharmaceutical, cosmetic, nutraceutical, and food industries, as well as providing an overview of regulatory and health concerns. Nanoemulsion-based delivery systems can enhance the water-dispersibility, stability, and bioavailability of hydrophobic bioactive compounds. Nevertheless, they must be carefully formulated to obtain the required functional attributes. In particular, the concentration, size, charge, and physical properties of the nano-droplets must be taken into consideration for each specific application. Before launching a nanoscale product onto the market, determination of physicochemical characteristics of nanoparticles and their potential health and environmental risks should be evaluated. In addition, legal, consumer, and economic factors must also be considered when creating these systems.