Essential oil nanoemulsions: Properties, development, and application in meat and meat products

Application of tea tree oil nanoemulsion pads in Lateolabrax japonicas fillets

Abstract

To improve the efficiency of biological preservatives, a novel slow-release system was constructed. The oil-in-water (O/W) nanoemulsions were prepared with tea tree essential oil (TTO) and its main components, 1,8-cineole (CN) and terpinen-4-oil (T4O) as core materials, and with tea saponin as surfactant. The preservation properties of the pad containing nanoemulsion slow-release system on Lateolabrax japonicus fillets were measured. The results showed that the nanoemulsion had good stability and can delay the release of essential oil, and the cumulative release percentage of TTO was as high as 81 % at 72 h. The establishment of nanoemulsions slow-release system effectively improved the preservation properties of the pad, and TTO nanoemulsion pad (TTO-NE-P) had the optimal preservation properties due to the synergistic effect of preservative ingredients and the sustained release system of the nanoemulsion. This study can provide technical support for the combined application of biological preservative agent and aquatic product pads.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-024-01812-9.

Effect of astaxanthin and carvacrol co-encapsulated emulsion and chitosan on the physicochemical, rheological, and antimicrobial properties in nitrite-free meat spread

The quality and safety of meat products are critical concerns in the food industry, and consumer demand for clean-label products is increasing. To meet these needs, this study aimed to develop a nitrite-free meat spread using an astaxanthin (0.04 wt%) and carvacrol (15 wt%) co-encapsulated emulsion (AE) and chitosan. Thermal stability and antimicrobial activity of prepared AE were evaluated. Nitrite-free meat spreads were formulated by adding astaxanthin and carvacrol-containing oil (AO), AE, and/or chitosan, and physicochemical, rheological, and antimicrobial properties were assessed. Adding AE, and/or 1 % chitosan improved the physicochemical and antimicrobial properties of the meat spreads. AE increased the unsaturated fatty acid content, improved redness, reduced cooking loss, and enhanced emulsion stability. Microsurface and rheological analyses revealed a more uniform fat/oil distribution and lower textural values in samples containing AE. AE and/or chitosan also enhanced microbiological stability. Correlation analysis suggested that AE and/or chitosan could effectively replace nitrite.

Effects of Different Preservation Techniques on Microbial and Physicochemical Quality Characteristics of Sauced Beef Under Chilled Storage

This study investigates the effects of different preservation methods-tray packing (control), vacuum packing (T1), and tray packing with 2 mg/mL pepper essential oil (T2)-on the quality of sauced beef during 4 °C storage for 1, 5, 9, and 13 days. The results revealed that T2 significantly inhibited microbial growth, as reflected by reduced total aerobic counts (TACs), minimized lipid oxidation (indicated by lower thiobarbituric acid reactive substances (TBARSs)), and reduced protein degradation (evidenced by decreased total volatile basic nitrogen (TVB-N)). Additionally, T2 delayed the reduction in inosine-5'-monophosphate (IMP) and accumulation of hypoxanthine (Hx), effectively extending shelf life and preserving sensory quality. T1 also showed beneficial effects in limiting oxygen-related spoilage, as demonstrated by lower TAC and TBARS levels. In contrast, the control group showed limited effectiveness in preserving the quality of sauced beef, as indicated by higher microbial counts and more pronounced lipid and protein degradation. These findings provide a theoretical basis for improving sauced beef preservation by highlighting the effectiveness of different packaging methods and the potential of pepper essential oil as a natural preservative.

The Current Status, Hotspots, and Development Trends of Nanoemulsions: A Comprehensive Bibliometric Review

Nanoemulsions, which are characterized by their nanometer-scale droplets, have gained significant attention in different fields, such as medicine, food, cosmetics, and agriculture, because of their unique properties. With an increasing number of countries engaging in research on nanoemulsions, interest in their properties, preparation methods, and applications has increased. Hence, tracing the relevant research on nanoemulsions published in the past ten years on a global scale, by conducting data mining and visualization analysis on a sufficiently large text dataset through bibliometrics, sorting out and summarizing certain indicators, the development history, research status and research hotspots in the field of nanoemulsions can be clearly revealed, providing reference value and significance for subsequent research. This bibliometric review examines the research landscape of nanoemulsions from 2013-2023 via the SCI-E and SSCI databases, providing insights into the current status, hotspots, and future trends of this field. To offer a comprehensive overview, this analysis includes publication counts, author keywords, institutional contributions, research areas, prolific authors, highly cited papers and hot research papers. The findings reveal that China led in nanoemulsions research, followed by USA, India, and Brazil, with the University of Massachusetts emerging as a key player with the highest average number of citations per article (ACPP) and h-index. Food Chemistry, Pharmaceutics, and the Journal of Drug Delivery Science and Technology are among the top journals publishing in this area. Chemistry, pharmacology, and pharmacy emerged as the primary research domains, with McClements DJ as the most prolific and influential author. In keyword analysis, essential oil nanoemulsions are currently the main preparation direction, and various characteristics of nanoemulsions, such as their bioavailability, stability, biocompatibility, and antioxidant and antibacterial properties, have also been studied extensively. Research hotspots are focused mostly on the development of new applications and technologies for nanoemulsions.

Impacts of chitosan/pullulan/carvacrol film on the quality and microbial diversity of refrigerated goat meat

In this study, our previously prepared chitosan/pullulan film (CS/PU) and chitosan/pullulan/carvacrol film (CS/PU/CAR) were applied to goat meat preservation, the dynamic changes in quality and microbial communities of goat meat during chilled storage (4 °C) were investigated, and the fresh-keeping effects of the two biodegradable antibacterial films on goat meat were comprehensively evaluated. The results showed that when the goat meat was wrapped with CS/PU or CS/PU/CAR films during chilled storage, the total plate count and total volatile basic nitrogen (TVB-N) could be inhibited significantly, but the CS/PU/CAR film has a better fresh-keeping effect. Furthermore, during the chilled storage of goat meat, CS/PU/CAR film also could inhibit the production of alcohol compounds and the growth of Pseudomonas spp., thereby slowing down the meat's deterioration and extending the goat meat's shelf life to about 13 days. This study can provide a reference for the application of active packaging film of fresh goat meat.

Recent progress in the source, extraction, activity mechanism and encapsulation of bioactive essential oils

There is growing concern about the potential risks posed by synthetic additives in industrial products, such as foods, cosmetics, agrochemicals, and personal care products. Many plant-derived essential oils (EOs) have been shown to exhibit excellent antibacterial, antifungal, antiviral, and antioxidant activities, and may therefore be used as natural preservatives in these applications. However, most EOs have relatively low water solubility and are prone to chemical degradation during storage. The degradation products of EOs can be toxic and may not be able to fully exert their biological activity, which limits their application. Typically, these challenges can be overcome by encapsulating the essential oil in an appropriate colloid delivery system. This article begins by reviewing the sources, extraction, and activity mechanisms of EOs, and then highlights plant-based encapsulation technologies that can be used to enhance their efficacy. Finally, the potential applications of plant essential oil encapsulation system are discussed.

Gelatin/polyvinyl alcohol films loaded with doubly stabilized clove essential oil chitosomes: Preparation, characterization, and application in packing marinated steaks

In this study, a promising active food-packaging film of Gelatin/polyvinyl alcohol (GEL/PVA) integrated with doubly stabilized clove essential oil chitosome nanoparticles (CNP) was developed to maintain the freshness of marinated steaks. Results from the XRD and SEM experiments indicated excellent compatibility between the CNP and GEL/PVA matrix. Additionally, CNP was found to introduce more free hydroxyl groups, enhance the water retention and surface wettability of the CNP-GEL/PVA (C-G/P) film, and significantly reduce the swelling index from 963.78% to 495.11% (p < 0.05). Notably, the highest tensile strength and elongation at break (53.745 MPa and 46.536%, respectively) were achieved with the addition of 30% (v/v, based on the volume of gelatin) CNP; UVC was fully absorbed with 40% CNP; and films containing 60% CNP showed optimal inhibition of both Staphylococcus aureus and Escherichia coil, extending the shelf life of marinated steak from 3 to 7 days.

On-going issues regarding biofilm formation in meat and meat products: challenges and future perspectives

The meat industry has been significantly threatened by the risks of foodborne microorganisms and biofilm formation on fresh meat and processed products. A microbial biofilm is a sophisticated defensive mechanism that enables bacterial cells to survive in unfavorable environmental circumstances. Generally, foodborne pathogens form biofilms in various areas of meat-processing plants, and adequate sanitization of these areas is challenging owing to the high tolerance of biofilm cells to sanitization compared with their planktonic states. Consequently, preventing biofilm initiation and maturation using effective and powerful technologies is imperative. In this review, novel and advanced technologies that prevent bacterial and biofilm development via individual and combined intervention technologies, such as ultrasound, cold plasma, enzymes, bacteriocins, essential oils, and phages, were evaluated. The evidence regarding current technologies revealed in this paper is potentially beneficial to the meat industry in preventing bacterial contamination and biofilm formation in food products and processing equipment.

Sublethal effects of nanoformulated Mentha pulegium L. essential oil on the biological and population growth parameters of the greenhouse whitefly, Trialeurodes vaporariorum, (Hemiptera: Aleyrodidae)

We evaluated the toxicity and sublethal effects of essential oil (Mentha pulegium L.) and its nanoformulation against greenhouse whitefly, Trialeurodes vaporariorum, which is one of the most destructive pests of a wide range of crops. The essential oil was extracted from the plant by steam distillation using a Clevenger apparatus, and 14 chemical components of M. pulegium were identified using gas chromatography-mass spectrometry. The results illustrated that monoterpenoids were main characterized components including pulegone (%66), menthofren (%10.54), 1, 8 Cineole (%8.36), betapenin (%3.49) and limonene (%2.01). The nanoformulation was characterized using dynamic light scattering (DLS), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), revealing that the particles were spherical in shape with an average size of 156.40 nm. The leaf dipping was used for the bioassays. The obtained LC50 and LC25 values of treatments indicated that the nanoformulation of essential oil (LC50: 2418.96 and LC25: 1724. 25 ppm) was more toxic than the pure of M. pulegium oil (LC50: 3223.083 and LC25: 779.439 ppm ppm) against greenhouse whitefly adults after 24 h. The life table data were analyzed based on the age-stage, two-sex life table theory using computer program of TWOSEX-MSChart. Also, the sublethal concentration (LC25) of its nanoformulation led to delaying in preadult stage and decreased the adult longevity, and fecundity compared to treatments. Moreover, the sublethal concentration of either M. pulegium oil or its nanoformulation affected the population growth parameters of T.vaporariorum compared to the control. However, the net reproductive rate (R0), intrinsic rate of increase (r), finite rate of increase (λ), of adults who exposed to the nanoformulation was lower than the pure form of M. pulegium. The overall results demonstrated that the nanoformulation of M. pulegium has the most lethal and sublethal effects on greenhouse whitefly compared with the pure form of essential oil which can be consider in integrated pest management program (IPM) of this pest.

Study on the stability, functional activity and preservation effect of oregano essential oil Pickering emulsion with different proportions of chicken bone gelatin/bacterial cellulose during storage

In this study, chicken bone gelatin (CBG) was extracted as a new substitute for traditional pig bone gelatin, and bacterial cellulose (BC) was used as the compound to prepare Oregano essential oil (OEO) Pickering emulsion. To explore a protein/polysaccharide emulsion system that can effectively prolong the functional activity of OEO during storage. The results indicated that the variation in CBG and BC content significantly influenced the physicochemical properties of the emulsions. The optimal formulation of OEO Pickering emulsion, prepared with a CBG-BC ratio of 6:2 (v/v), exhibited superior characteristics including appearance, encapsulation efficiency, and stability during preservation. After 7 d of storage at 4 °C, the rheological properties remained stable, with no significant differences observed in antioxidant and antibacterial activities. It was verified in the beef fresh-keeping experiment that the shelf life of beef samples in the 6-2-2 treatment group was 6 d longer than that in the control group and 3 d longer than that in the pure OEO group. This experiment enhanced the utilization of poultry by-products and provided a valuable reference for exploring suitable protein-polysaccharide systems embedding active substances for food preservation.

Developing novel hybrid bilayer nanofibers based on polylactic acid with impregnation of chamomile essential oil and gallic acid-stabilized silver nanoparticles

This study presents fabrication and characterization of novel chamomile essential oil (CMO)/gallic acid-stabilized silver nanoparticles (gallic acid-nanosilver, GNS), embedded into polylactic acid (PLA)-based hybrid bilayer nanofibers (NFs). Where CMO was impregnated into polyvinyl alcohol (PVA)-polyethylene glycol (PEG) solution and electrospun simultaneously with PLA to obtain PLA/PVA-PEG-CMO NFs (PLA/CMO A2). Meanwhile, GNS were added to PVA-PEG-CMO and electrospun to obtain PLA/PVA-PEG-CMO-GNS NFs (PLA/CMO-GNS A3). Where pure PLA/PVA-PEG NFs were coded pure PLA/A1. Physicochemical properties of fabricated bilayer-NFs were performed using various approaches. Besides, porosity%, swelling, biodegradability, CMO release pattern, antioxidant, antibacterial activity and cytotoxicity were investigated. Study investigation revealed PLA-based bilayer NFs exhibited a biphasic release profile for impregnated CMO. Due to presence of GA, antioxidant property and biocompatibility of PLA/CMO-GNS A3 was superior compared to pure PLA/A1 and PLA/CMO A2. Antibacterial activity was enhanced in presence of CMO in PLA/CMO A2 than pure PLA/A1. Furthermore, addition of GNS in PLA/CMO-GNS A3 displayed highest antibacterial activity due to synergy of CMO/GNS. Finally, MTT assay with HFB4 fibroblasts demonstrated absence of cytotoxicity of bilayer-based NFs. Thus, study suggests that developed PLA/PVA-PEG NFs could be a promising candidate for tissue regeneration and food edible packaging in particular when impregnated with both CMO/GNS.

Multi-functional reinforced food packaging using delivery carriers: A comprehensive review of preparation, properties, and applications

With the rapid development of globalization, food packaging takes on more responsibility, while guaranteeing product quality and safety. In this context, the health risks associated with chemically synthesized additives and inorganic nanoparticles have opened a new chapter in the reinforcement of food packaging with natural active ingredients. Various delivery carriers have been developed to overcome the limitations of poor stability, uneven dispersion, and low bioavailability of natural active ingredients. The combination of encapsulation technologies can increase the biocompatibility of the active ingredient with the packaging material. Moreover, the protective and slow-release effects of the carrier matrix on the active ingredients are desirable for the reinforcement of food packaging. This review presents the latest advances in the application of delivery systems in food packaging, including the types of delivery systems used in food packaging, reinforced properties of food packaging, and potential applications in the food industry. Previous scientific studies found that active ingredient-loaded delivery carriers increased the effectiveness of food packaging in preventing food spoilage. Furthermore, the integration of active packaging with smart food packaging exhibits the synergistic effects of freshness monitoring and quality preservation. This review also discusses the challenges and trends in reinforcing food packaging with delivery carriers under a synergistic strategy that will provide new ideas and insights for the development and application of innovative food packaging.

Effect of Litsea cubeba and Cinnamon Essential Oil Nanoemulsion Coatings on the Preservation of Plant-Based Meat Analogs

Plant-based meat analogs (PBMAs) are promising sustainable food sources. However, their high moisture and protein contents make them prone to microbial deterioration, limiting their shelf life and sensory appeal. This study explored enhancing PBMAs' shelf life using nanoemulsions of Litsea cubeba and cinnamon essential oils, emulsified with chitosan and Tween 80. The composite nanoemulsion, produced through high-pressure homogenization, exhibited a droplet size of 4.99 ± 0.03 nm, a polydispersity index (PDI) of 0.221 ± 0.008, and a zeta potential of 95.13 ± 2.67 mV, indicating remarkable stability (p < 0.05). Applied to PBMAs stored at 4 °C, it significantly improved color and pH balance and reduced thiobarbituric acid reactive substances and cooking loss. Most notably, it inhibited the growth of Escherichia coli and Staphylococcus aureus, curbing spoilage and protein oxidation, thereby extending the products' shelf life and preserving sensory quality. As shown above, the encapsulation of LCEO/CEO in nanoemulsions effectively inhibits spoilage and deterioration in PBMAs, improving flavor and quality more than direct addition. Future studies should explore using various essential oils and emulsifiers, as well as alternative encapsulation techniques like microcapsules and nanoparticles, to further prevent PBMA deterioration.

Polyvinyl alcohol/soybean isolate protein composite pad with enhanced antioxidant and antimicrobial properties induced by novel ternary nanoparticles for fresh pork preservation

In this study, oregano essential oil (OEO)-loaded soluble soybean polysaccharide (SSPS) -nisin nanoparticles (ONSNPs) were formulated through electrostatic attraction-driven and hydrophobic interactions utilizing SSPS, nisin, and OEO as raw materials. ONSNPs were integrated into polyvinyl alcohol (PVA) and soybean protein isolate (SPI) matrices to create composite pads (PS-ONSNPs) by physically cross-linked using a simple freeze-thaw cycling process. The effects of ONSNPs content on the structure and physicochemical properties were evaluated. The results revealed that strong intermolecular interactions between ONSNPs and the PS matrices affected the crystallinity, microstructure, and thermal stability of the pads. Upon incorporating 5 % to 15 % ONSNPs, the structure of composite pads became denser, and the mechanical properties and water resistance were enhanced. Concurrently, the PS-ONSNPs pads facilitated the protection and controlled release of OEO. Furthermore, ONSNPs significantly improved the antioxidant activity of the pads and effectively inhibited the growth of Staphylococcus aureus and Escherichia coli. The prepared PS-ONSNPs 15 % pad was applied to storage experiments of fresh pork, which could extend the shelf life of meat to 10-12 days under 4 °C storage conditions. Therefore, the composite pad devised in this research holds promise as a viable option for intelligent active packaging of fresh meat.

Encapsulation of eucalyptus and Litsea cubeba essential oils using zein nanopolymer: Preparation, characterization, storage stability, and antifungal evaluation

The encapsulation of essential oils (EOs) in protein-based biopolymeric matrices stabilized with surfactant ensures protection and physical stability of the EO against unfavorable environmental conditions. Accordingly, this study prepared zein nanoparticles loaded with eucalyptus essential oil (Z-EEO) and Litsea cubeba essential oil (Z-LEO), stable and with antifungal activity against Colletotrichum lindemuthianum, responsible for substantial damage to bean crops. The nanoparticles were prepared by nanoprecipitation with the aid of ultrasound treatment and characterized. The nanoparticles exhibited a hydrodynamic diameter close to 200 nm and PDI < 0.3 for 120 days, demonstrating the physical stability of the carrier system. Scanning electron microscopy and Transmission electron microscopy revealed that the nanoparticles were smooth and uniformly distributed spheres. Fourier-transform infrared spectroscopy showed interaction between zein and EOs through hydrogen bonding and hydrophobic interactions. Thermogravimetric analysis demonstrated the thermal stability of the nanoparticles compared to pure bioactive compounds. The nanoparticles exhibited a dose-dependent effect in inhibiting the fungus in in vitro testing, with Z-EEO standing out by inhibiting 70.0 % of the mycelial growth of C. lindemuthianum. Therefore, the results showed that zein has great potential to encapsulate hydrophobic compounds, improving the applicability of the bioactive compound as a biofungicide, providing protection for the EO.

Improving the storage quality of Harbin red sausages by quaternized chitosan/sodium alginate coating curcumin nano-emulsion

In this study, the effect of sodium alginate and quaternized chitosan bis-polysaccharide-based shell transport curcumin nano-emulsions (Cur@QCS/SA) on the microbiological, physicochemical properties, quality characteristics of Harbin red sausage during storage is investigated. According to the microbiological results, the shelf life of Harbin red sausage is extended from 3 d to 6 d by adding 0.15% Cur@QCS/SA, and Bacillus is the most predominant bacterial before 6 d. Additionally, the physicochemical properties change significantly, the pH, weight loss (WL), water holding capacity (WHC), water activity (aw), L*, and a* of red sausage decrease gradually with the extension of storage time, as well as b*, lipid oxidation, proteolysis increase significantly (P < 0.05). Secondly, it is found that 0.15% treatment group can better maintain the quality characteristics of Harbin red sausage according to texture profile analysis (TPA), electronic nose (E-nose), and electronic tongue (E-tongue) (P < 0.05). This study provides a new way for nano-emulsions in food applications and a new option for the preservation of Harbin red sausage as well as other low-temperature meat products.

Preparation of Complex Polysaccharide Gels with Zanthoxylum bungeanum Essential Oil and Their Application in Fish Preservation

In this study, novel functional ZEO-complex gels were prepared using sodium alginate, inulin, grape seed extract (GSE), and Zanthoxylum bungeanum essential oil (ZEO) as the primary raw materials. The effect of the addition of inulin, GSE, and ZEO on water vapor permeability (WVP), tensile strength (TS), and elongation at break (EAB) of ZEO-complex polysaccharide gels was investigated. A comprehensive score (Y) for evaluating the characteristics of ZEO-complex polysaccharide gels was established by principal component analysis. MATLAB analysis and box-Behnken design describe each factor's four-dimensional and three-dimensional interactions. It was found that Y could reach the maximum value when the ZEO addition was at a moderate level (C = 2%). The optimum preparation process of ZEO-complex polysaccharide gels was as follows: the addition of inulin was at 0.84%, the addition of GSE was at 0.04%, and the addition of ZEO was at 2.0785%; in this way, the Y of ZEO-complex polysaccharide gels reached the maximum (0.82276). Optical scanning and X-ray diffraction tests confirmed that the prepared ZEO-complex gels have a smooth and continuous microstructure, good water insulation, and mechanical properties. The storage test results show that ZEO-complex polysaccharide gels could play a significant role in the storage and fresh-keeping of grass carp, and the physicochemical properties of complex polysaccharide gels were improved by adding ZEO. In addition, according to the correlation of fish index changes during storage, adding ZEO in complex polysaccharide gels was closely correlated with the changes in fish TBARS and TVB-N oxidation decay indices. In conclusion, the ZEO-complex polysaccharide gels prepared in this study had excellent water insulation, mechanical properties, and outstanding fresh-keeping effects on grass carp.

Impact of Thyme Essential Oil on the Aroma Profile and Shelf Life of Vacuum-Packed Minced Turkey Meat

There is considerable interest in the use of essential oils for food preservation, but their effect on the aroma profile of a product is poorly understood. This study investigated the effect of thyme essential oil (EO) addition at increasing concentrations (0.005, 0.01, 0.02, and 0.03% v/w) on the volatile compound composition of vacuum-packed minced turkey meat after storage for 8 days at 1-2 °C. The aroma profile of the meat was determined using the HS-SPME/GCMS (headspace solid-phase microextraction/gas chromatography-mass spectrometry) method. The results were also analysed by PCA (principal component analysis). The addition of thyme EO had a modifying effect on the aroma profile of meat-derived components, e.g., the formation of benzeneacetaldehyde, benzyl alcohol, 4,7-dimethylbenzofuran, hexathiane, hexanal, and 1-hexanol was reduced and the appearance of 9-hexadecenoic acid was observed in the stored samples. The increase in EO concentration affected the levels of its individual components in the meat headspace in different ways. In terms of fat rancidity indices, even a 0.005% addition of this essential oil significantly reduced the peroxide value. Quantitative descriptive analysis (QDA) showed that the addition of thyme EO reduced or masked the intensity of unpleasant odours associated with meat spoilage. In the aroma analysis, the turkey with 0.02% v/w EO scored highest, and pleasant citrus notes were found.

Comparison of Gamma-Oryzanol Nanoemulsions Fabricated by Different High Energy Techniques

Gamma-oryzanol (GO) is a bioactive compound that, due to its biological characteristics, can be added to a food matrix. However, the bioactive compound is difficult to incorporate due to its low solubility and stability. A nanoemulsion allows substances to be packaged in nanometric sizes, improving their bioavailability. In this work, a GO nanoemulsion was developed using high-energy techniques. The methodological process began with the formulation of the coarse emulsion, where the emulsifiers (sodium caseinate and citrus pectin), diluent (rice bran oil), and pH were varied to find the most stable formulation. The coarse emulsion was subjected to four high-energy techniques (conventional homogenization, high-pressure homogenization, ultra-high-pressure homogenization, and ultrasonication) to reduce the droplet size. A physical-stability test, rheological-behavior test, image analysis, and particle-size-and-distribution test were conducted to determine which was the best technique. The formulation with the highest stability (pH 5.3) was composed of 87% water, 6.1% sodium caseinate, 0.6% citrus pectin, 6.1% rice bran oil, and 0.2% GO. The ultrasonic treatment obtains the smallest particle size (30.1 ± 1 nm), and the high-pressure treatment obtains the greatest stability (TSI < 0.3), both at 0 and 7 days of storage. High-energy treatments significantly reduce the droplet size of the emulsion, with important differences between each technique.

Zein and tannic acid hybrid particles improving physical stability, controlled release properties, and antimicrobial activity of cinnamon essential oil loaded Pickering emulsions

Pickering emulsion loading essential oil has demonstrated a promising strategy as delivery system in food preservation, but localization in stability and antimicrobial activity limits application. In this study, Pickering emulsions co-loaded with tannic acid and cinnamon essential oil (ZTC) have been developed based on zein and tannic acid complexes (ZT) mediated interfacial engineering. Fourier transform infrared, fluorescence spectroscopy, and molecular docking results indicated tannic acid altered the structural of zein. Interfacial tension results indicated that tannic acid accelerated the adsorbed speed of zein particles by decreased interfacial tension (11.99-9.96 mN/m). ZT5 formed a viscoelastic and dense layer in oil-water interface than that for other ZTs, which improved stability and control release performance of ZTC. Furthermore, the ZTC showed an effective antimicrobial activity against spoilage organisms Pseudomonad paralactis MN10 and Lactobacillus sakei VMR17. These findings provide new insight for developing co-loaded multiple antimicrobial agents within Pickering emulsion as a delivery system.

Intrinsic properties and extrinsic factors of food matrix system affecting the effectiveness of essential oils in foods: a comprehensive review

Essential oils (EOs) have been proved as natural food preservatives because of their effective and wide-spectrum antimicrobial activity. They have been extensively explored for potential applications in food industry, and substantial progresses have been achieved. However well EOs perform in antibacterial tests in vitro, it has generally been found that a higher level of EOs is needed to achieve the same effect in foods. Nevertheless, this unsimilar effect has not been clearly quantified and elaborated, as well as the underlying mechanisms. This review highlights the influence of intrinsic properties (e.g., oils and fats, carbohydrates, proteins, pH, physical structure, water, and salt) and extrinsic factors (e.g., temperature, bacteria characteristics, and packaging in vacuum/gas/air) of food matrix systems on EOs action. Controversy findings and possible mechanism hypotheses are also systematically discussed. Furthermore, the organoleptic aspects of EOs in foods and promising strategies to address this hurdle are reviewed. Finally, some considerations about the EOs safety are presented, as well as the future trends and research prospects of EOs applications in foods. The present review aims to fill the evidenced gap, providing a comprehensive overview about the influence of the intrinsic and extrinsic factors of food matrix systems to efficiently orientate EOs applications.

Self-Assembled Nanocarrier Delivery Systems for Bioactive Compounds

Although bioactive compounds (BCs) have many important functions, their applications are greatly limited due to their own defects. The development of nanocarriers (NCs) technology has gradually overcome the defects of BCs. NCs are equally important as BCs to some extent. Self-assembly (SA) methods to build NCs have many advantages than chemical methods, and SA has significant impact on the structure and function of NCs. However, the relationship among SA mechanism, structure, and function has not been given enough attention. Therefore, from the perspective of bottom-up building mechanism, the concept of SA-structure-function of NCs is emphasized to promote the development of SA-based NCs. First, the conditions and forces for occurring SA are introduced, and then the SA basis and molecular mechanism of protein, polysaccharide, and lipid are summarized. Then, varieties of the structures formed based on SA are introduced in detail. Finally, facing the defects of BCs and how to be well solved by NCs are also elaborated. This review attempts to describe the great significance of constructing artificial NCs to deliver BCs from the aspects of SA-structure-function, so as to promote the development of SA-based NCs and the wide application of BCs.

Ultrasound-Assisted Nanoemulsion Loaded with Optimized Antibacterial Essential Oil Blend: A New Approach against Escherichia coli, Staphylococcus aureus, and Salmonella Enteritidis in Trout (Oncorhynchus mykiss) Fillets

This study aimed to obtain and characterize an oil-in-water nanoemulsion (NE) loaded with an in vitro optimized bactericidal essential oil blend of 50% oregano, 40% thyme, and 10% lemongrass and to evaluate its potential at three different concentrations (0.5%, 1%, and 2%) in the inactivation of Escherichia coli, Staphylococcus aureus, and Salmonella enterica serotype Enteritidis inoculated in rainbow trout fillets stored at 4 °C for 9 days. Regarding the NE, the nanometric size (<100 nm) with low polydispersion (0.17 ± 0.02) was successfully obtained through ultrasound at 2.09 W/cm2. Considering the three concentrations used, S. Enteritidis was the most susceptible. On the other hand, comparing the concentrations used, the NE at 2% showed better activity, reducing S. Enteritidis, E. coli, and S. aureus by 0.33, 0.20, and 0.73 log CFU/g, respectively, in the trout fillets. Thus, this data indicates that this is a promising eco-friendly alternative to produce safe fish for consumption and reduce public health risks.

Innovative Encapsulation Strategies for Food, Industrial, and Pharmaceutical Applications

Bioactive metabolites obtained from fruits and vegetables as well as many drugs have various capacities to prevent or treat various ailments. Nevertheless, their efficiency, in vivo, encounter many challenges resulting in lower efficacy as well as different side effects when high doses are used resulting in many challenges for their application. Indeed, demand for effective treatments with no or less unfavorable side effects is rising. Delivering active molecules to a particular site of action within the human body is an example of targeted therapy which remains a challenging field. Developments of nanotechnology and polymer science have great promise for meeting the growing demands of efficient options. Encapsulation of active ingredients in nano-delivery systems has become as a vitally tool for protecting the integrity of critical biochemicals, improving their delivery, enabling their controlled release and maintaining their biological features. Here, we examine a wide range of nano-delivery techniques, such as niosomes, polymeric/solid lipid nanoparticles, nanostructured lipid carriers, and nano-emulsions. The advantages of encapsulation in targeted, synergistic, and supportive therapies are emphasized, along with current progress in its application. Additionally, a revised collection of studies was given, focusing on improving the effectiveness of anticancer medications and addressing the problem of antimicrobial resistance. To sum up, this paper conducted a thorough analysis to determine the efficacy of encapsulation technology in the field of drug discovery and development.

Synergistic stabilization of garlic essential oil nanoemulsions by carboxymethyl chitosan/Tween 80 and application for coating preservation of chilled fresh pork

Garlic essential oil (GEO) is a potential natural antioxidant and antimicrobial agent for food preservation, but its intrinsic low water-solubility, high volatility and poor stability severely limit its application and promotion. In this work, we investigated the synergistic stabilization of the GEO-in-water nanoemulsion using carboxymethyl chitosan (CCS) and Tween 80 (TW 80). Additionally, the nanoemulsion was fabricated through high-pressure microfluidization and utilized for the coating-mediated preservation of chilled pork. The garlic essential oil nanoemulsion (GEON) with 3.0 % CCS and 3.0 % TW 80 exhibited more homogeneous droplet size (around 150 nm) and narrower size distribution, while maintained long-term stability with no significant change in size during 30 d storage. Compared with free GEO, the GEONs exhibited a higher scavenging capacity to DPPH and ABTS free radicals as well as higher inhibitory effects against Escherichia coli and Staphylococcus aureus, suggesting that the encapsulation of GEO in nanoemulsion considerably improved its antioxidant and antibacterial activities. Furthermore, the results of coating preservation experiments showed that the GEON coating effectively expanded the shelf-life of chilled fresh pork for approximately one week. Altogether, this study would guide the development of GEO-loaded nanoemulsions, and promote GEON as a promising alternative for coating preservation of chilled fresh meat.

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.

Chitosan/alginate/pectin biopolymer-based Nanoemulsions for improving the shelf life of refrigerated chicken breast

This study investigated the use of nanoemulsions and various polymer coatings to enhance the quality and shelf life of chicken breast. This comprehensive study explored the antibacterial activity of essential oils (EOs) against Escherichia coli and Staphylococcus aureus, as well as the characterization of nanoemulsions (Nes) and nanoemulsion-based coatings. The antimicrobial potential of EOs, such as cinnamon, tea tree, jojoba, thyme, and black cumin seed oil, was evaluated against microorganisms, and thyme oil exhibited the highest inhibitory effect, followed by cinnamon and tea tree oil by disk diffusion analysis. The MIC and MBC values of EOs were found between 0.16-2.5 mg/mL and 0.16-5 mg/mL, respectively, while thyme EO resulted in the lowest values showing its antimicrobial potential. Then, the essential oil nanoemulsions (EONe) and their coatings, formulated with thyme oil, alginate, chitosan, and pectin, were successfully characterized. Optical microscope observations confirmed the uniform distribution of droplets in all (EONe), while particle size analysis demonstrated multimodal droplet size distributions. The EONe-chitosan coating showed the highest efficacy in reducing cooking loss, while the EONe-chitosan, EONe-alginate, and EONe-pectin coatings displayed promising outcomes in preserving color stability. Microbial analysis revealed the significant inhibitory effects of the EONe-chitosan coating against mesophilic bacteria, psychrophilic bacteria, and yeasts, leading to an extended shelf life of chicken breast. These results suggest the potential application of thyme oil and NE-based coatings in various industries for antimicrobial activity and quality preservation.

Effect of clove essential oil nanoemulsion on physicochemical and antioxidant properties of chitosan film

This study evaluated the physicochemical and antioxidant properties of clove essential oil (0, 0.2, 0.4, 0.6, 0.8, 1.0 % v/v) nanoemulsion (CEON) loaded chitosan-based films. With the increasing concentrations of the CEON, the thickness, b* and ΔE values of the films increased significantly (P < 0.05), while L* and light transmission dropped noticeably (P < 0.05). The hydrogen bonds formed between the CEON and chitosan could be demonstrated through Fourier-transform infrared spectra, indicating their good compatibility and intermolecular interactions. Furthermore, the added CEON considerably reduced the crystallinity and resulted in a porous structure of the films, as observed through X-ray diffraction plots and scanning electron microscopy images, respectively. This eventually led to a drop in both tensile strength and moisture content of the films. Moreover, the antioxidant properties were significantly enhanced (P < 0.05) with the increase in the amount of clove essential oil (CEO) due to the encapsulation of CEO by the nanoemulsion. Films containing 0.6 % CEO had higher elongation at break, higher water contact angle, lower water solubility, lower water vapor permeability, and lower oxygen permeability than the other films; therefore, such films are promising for application in meat preservation.

Improved sustained-release properties of ginger essential oil in a Pickering emulsion system incorporated in sodium alginate film and delayed postharvest senescence of mango fruits

The insufficient water vapor barrier and mechanical capacity of sodium alginate (SA) film limited its application in fruit preservation. Herein, cellulose nanocrystals (CNCs) were used to stabilize Pickering emulsion. Then, we prepared SA composite films. Ginger essential oil (GEO) was loaded as antimicrobials and antioxidants. Finally, the application on mangos were investigated. Compared to coarse emulsion, Pickering emulsion and its film-formation-solution showed more stable system and larger droplet size. The emulsion significantly changed the properties of SA film. Specifically, CNCs improved the thermal, tensile, and barrier properties of the film and GEO enhanced the ultraviolet-visible light barrier capacity. Additionally, the SA/CNC film possessed a homogeneous micromorphology which had a sustained-release effect on GEO, thus maintaining high postharvest quality and long-term bioavailability for mangos. In conclusion, the film prepared via Pickering emulsion showed satisfactory properties which had great potential in fruit preservation.

Characterization of bergamot essential oil: chemical, microbiological and colloidal aspects

Citrus bergamia is a citric species known as bergamot. The species is widely used due to its derivatives, such as juices, extracts, and essential oil. Specifically, the bergamot essential oil (BEO) is of great interest, with a chemical composition rich in terpenes and esters. Considering its chemical composition, bioactivity, and great economic potential, the characterization of BEO should be studied. However, this essential oil is almost unexplored in terms of a characterization associated with colloids. Chemical characterization was carried out by gas-chromatography coupled to a mass spectrometer and by gas-chromatography coupled to a flame ionization detector. Antibacterial activity against Staphylococcus aureus and Escherichia coli was carried out to confirm the bioactivity of this important essential oil. Dynamic light scattering analysis was performed to create a pattern of droplet size distribution of BEO. Major compounds of BEO were linalyl acetate, limonene, and linalool. The BEO was active against E. coli and presented a MIC value of 2.000 µg/mL, while values of MIC and MBC higher than 2.000 µg/mL were observed for S. aureus. The dynamic light scattering analysis revealed a mean hydrodynamic diameter of 65.7 ± 2.2 nm. After a 1:10 dilution it was observed reduction of mean diameter and enhancement of the percentagem of low size droplets, resepctively 44.1 ± 1.2 nm and 14.5 ± 0.5 nm (28.8 ± 1.2%). Higher droplets and reduced polydispersity index were observed after 1:100 dilution. In the present study, the chemical characterization was in accordance with the species, as the characteristic chemical markers of the species were found. Moreover, it has presented antibacterial activity as expected for the BEO. The analysis of the colloid showed a pattern of droplet size distribution following the Ostwald ripening mechanism after dilution.

Development and characterization of potential larvicidal nanoemulsions against Aedes aegypti

Plant-based insecticides offer advantages such as negligible residual effects, reduced risks to both humans and the environment, and immunity to resistance issues that plague conventional chemicals. However, the practical use of monoterpenes in insect control has been hampered by challenges including their poor solubility and stability in aqueous environments. In recent years, the application of nanotechnology-based formulations, specifically nanoemulsions, has emerged as a prospective strategy to surmount these obstacles. In this study, we developed and characterized nanoemulsions based on cymene and myrcene and assessed their toxicity both in vitro using human keratinocytes (HaCAT) cells and in an in vivo model involving Galleria mellonella larvae. Additionally, we investigated the insecticidal efficacy of monoterpenes against the mosquito Aedes aegypti, the primary dengue vector, via larval bioassay. Employing a low-energy approach, we successfully generated nanoemulsions. The cymene-based nanoemulsion exhibited a hydrodynamic diameter of approximately 98 nm and a zeta potential of -25 mV. The myrcene-based nanoemulsion displayed a hydrodynamic diameter of 118 nm and a zeta potential of -20 mV. Notably, both nanoemulsions demonstrated stability over 60 days, accompanied by controlled release properties and low toxicity towards HaCAT cells and Galleria mellonella larvae. Moreover, the nanoemulsions exhibited significant lethality against third-instar Aedes aegypti larvae at a concentration of 50 mg/L. In conclusion, the utilization of nanoemulsions encapsulating cymene and myrcene presents a promising avenue for overcoming the limitations associated with poor solubility and stability of monoterpenes. This study sheds light on the potential of the nanoemulsions as effective and environmentally friendly insecticides in the ongoing battle against mosquito-borne diseases.

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.

Critical assessment of the delivery methods of chemical and natural postharvest preservatives for fruits and vegetables: a review

Through a comprehensive review on preservative delivery methods in fruits and vegetables preservation, it becomes evident that majority of existing studies concentrate on the development and mechanisms of preservatives. However, a notable gap lies in comparative analysis of different delivery methods, despite the direct impact of delivery methods on preservation outcomes. Additionally, emerging delivery techniques have displayed promising potential in enhancing delivery efficiency and likewise preservation effectiveness.

Nanoemulsions (O/W) prepared from essential oil extracted from Melaleuca alternifolia: synthesis, characterization, stability and evaluation of anticancerous, anti-oxidant, anti-inflammatory and antidiabetic activities

Essential oil from Melaleuca alternifolia (also known as Tea tree essential oil, TTO) is used as traditional medicine and used as therapeutic in medicine, food and cosmetic sectors. However, this oil is highly unstable, volatile and prone to oxidation which limits its practical use. The objective of this study was synthesis of tea tree oil based O/W (oil/water) nanoemulsions (tea tree essential oil nanoemulsions, TNE) and evaluation of its biological potential. Physiological characterization was carried out using UV, fluorescent, and FT-IR techniques. Various biological activities such as anticancerous, antidiabetic and anti-inflammatory were also estimated. Pharmacokinetics study on TNE was carried out. Encapsulation efficiency of nanoemulsions was found to be 83%. Nanoemulsions were spherical in shape with globule size 308 nm, zeta potential -9.42 and polydispersity index was 0.31. Nanoemulsions were stable even after 50 days of storage at different temperatures. Anti-oxidant potential of TNE was conducted by various assays and IC50 were: Nitric oxide radical scavenging activity:225.1, DPPH radical scavenging activity:30.66, Iron chelating assay:38.73, and Iron reducing assay:39.36. Notable anticancer activity was observed with the percent cell viability of HeLa cells after treatment with 1, 2 and 5 µl of TNE was 82%, 41% and 24%, respectively. Antidiabetic study revealed that TNE inhibited -amylase in a dose-dependent manner, with 88% inhibition at its higher volume of 250 µl. Drug kinetic study revealed that nanoemulsions exhibited first-order model. Based on this, the possible role of M. alternifolia oil-based nanoemulsions in cosmetic, food, and pharma sectors has been discussed.

Biomedical Approach of Nanotechnology and Biological Risks: A Mini-Review

Nanotechnology has played a prominent role in biomedical engineering, offering innovative approaches to numerous treatments. Notable advances have been observed in the development of medical devices, contributing to the advancement of modern medicine. This article briefly discusses key applications of nanotechnology in tissue engineering, controlled drug release systems, biosensors and monitoring, and imaging and diagnosis. The particular emphasis on this theme will result in a better understanding, selection, and technical approach to nanomaterials for biomedical purposes, including biological risks, security, and biocompatibility criteria.

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.

Dual cross-linked starch hydrogel for eugenol encapsulation and the formation of hydrogen bonds on textural hydrogel

Physical and chemical cross-linked hydrogels combining N, N'-Methylenebisacrylamide (MBA)-grafted starch (MBAS) and sorbitol were successfully prepared and encapsulated with eugenol in this work. The dense porous structure with diameter of 10-15 μm and strong skeleton after restructuring inside the hydrogel was confirmed by SEM. The band shifts between 3258 cm^-1 and 3264 cm^-1 clarified the presence of a large number of hydrogen bonds in physical and chemical cross-linked hydrogels. The robust structure of the hydrogel was confirmed by mechanical and thermal property measurements. Molecular docking techniques were used to help understand the bridging pattern between three raw materials and to assess the advantageous conformation, which demonstrate sorbitol is beneficial to improve the characteristics of textural hydrogel by the formation of hydrogen bonds, creating a denser network, structural recombination and new intermolecular hydrogen bonds between starch and sorbitol afforded considerably junction zones. Compared to ordinary starch-based hydrogels, eugenol-loaded starch-sorbitol hydrogels (ESSG) exhibited a more attractive internal structure, swelling properties, viscoelasticity. Moreover, the ESSG showed excellent antimicrobial activity for typical undesired microorganisms in foods.

Next-generation meat preservation: integrating nano-natural substances to tackle hurdles and opportunities

The increasing global meat demand raises concerns regarding the spoilage of meat caused by microbial invasion and oxidative decomposition. Natural substances, as a gift from nature to humanity, possess broad-spectrum bioactivity and have been utilized for meat preservation. However, their limited stability, solubility, and availability hinder their further development. To address this predicament, advanced organic nanocarriers provide an effective shelter for the formation of nano-natural substances (NNS). This review comprehensively presents various natural substances derived from plants, animals, and microorganisms, along with the challenges they face. Subsequently, the potential of organic nanocarriers is explored, highlighting their distinct features and applicability, in addressing these challenges. The review methodically examines the application of NNS in meat preservation, with a focus on their pathways of action and preservation mechanisms. Furthermore, the outlook and future trends for NNS applications in meat preservation are concluded. The theory and practice summary of NNS is expected to serve as a catalyst for advancements that enhance meat security, promote human health, and contribute to sustainable development.

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.

Characterization of Nanoemulsions Stabilized with Different Emulsifiers and Their Encapsulation Efficiency for Oregano Essential Oil: Tween 80, Soybean Protein Isolate, Tea Saponin, and Soy Lecithin

The use of the appropriate emulsifier is essential for forming a stable nanoemulsion delivery system that can maintain the sustained release of its contents. Health concerns have prompted the search for natural biopolymers to replace traditional synthetic substances as emulsifiers. In this study, an oregano essential oil (OEO) nanoemulsion-embedding system was created using soybean protein isolate (SPI), tea saponin (TS), and soy lecithin (SL) as natural emulsifiers and then compared to a system created using a synthetic emulsifier (Tween 80). The results showed that 4% Tween 80, 1% SPI, 2% TS, and 4% SL were the optimal conditions. Subsequently, the influence of emulsifier type on nanoemulsion stability was evaluated. The results revealed that among all the nanoemulsions, the TS nanoemulsion exhibited excellent centrifugal stability, storage stability, and oxidative stability and maintained high stability and encapsulation efficiency, even under relatively extreme environmental conditions. The good stability of the TS nanoemulsion may be due to the strong electrostatic repulsion generated by TS molecules, which contain hydroxyl groups, sapogenins, and saccharides in their structures. Overall, the natural emulsifiers used in our study can form homogeneous nanoemulsions, but their effectiveness and stability differ considerably.

Antimicrobial, Antibiofilm, and Anticancer Activities of Syzygium aromaticum Essential Oil Nanoemulsion

In the current study, clove oil nanoemulsion (CL-nanoemulsion) and emulsion (CL-emulsion) were prepared through an ecofriendly method. The prepared CL-nanoemulsion and CL-emulsion were characterized using dynamic light scattering (DLS) and a transmission electron microscope (TEM), where results illustrated that CL-nanoemulsion droplets were approximately 32.67 nm in size and spherical in shape, while CL-nanoemulsion droplets were approximately 225.8 nm with a spherical shape. The antibacterial activity of CL-nanoemulsion and CL-emulsion was carried out using a microbroth dilution method. Results revealed that the preferred CL-nanoemulsion had minimal MIC values between 0.31 and 5 mg/mL. The antibiofilm efficacy of CL-nanoemulsion against S. aureus significantly decreased the development of biofilm compared with CL-emulsion. Furthermore, results illustrated that CL-nanoemulsion showed antifungal activity significantly higher than CL-emulsion. Moreover, the prepared CL-nanoemulsion exhibited outstanding antifungal efficiency toward Candida albicans, Cryptococcus neoformans, Aspergillus brasiliensis, A. flavus, and A. fumigatus where MICs were 12.5, 3.12, 0.78, 1.56, and 1.56 mg/mL, respectively. Additionally, the prepared CL-nanoemulsion was analyzed for its antineoplastic effects through a modified MTT assay for evaluating apoptotic and cytotoxic effects using HepG2 and MCF-7 cell lines. MCF-7 breast cancer cells showed the lowest IC50 values (3.4-fold) in CL-nanoemulsion relative to that of CL-emulsion. Thus, CL-nanoemulsion induces apoptosis in breast cancer cells by inducing caspase-8 and -9 activity and suppressing VEGFR-2. In conclusion, the prepared CL-nanoemulsion had antibacterial, antifungal, and antibiofilm as well as anticancer properties, which can be used in different biomedical applications after extensive studies in vivo.

Study of nanoemulsions using carvacrol/MCT-(Oleic acid-potassium oleate)/ Tween 80 ®- water system by low energy method

Carvacrol is studied in different fields due to its microbial and antioxidant properties. Its use is limited because of the water insolubility and its strong taste. To overcome these problems, carvacrol has been successfully loaded into nanoemulsions. The low-energy emulsification method Phase Inversion Composition (PIC) is used to prepare oil-in-water nanoemulsions in the carvacrol/medium chain triglycerides (MCT)-(oleic acid-potassium oleate/Tween 80 ®)-water system. Oleic acid acts as a co-surfactant when it is neutralized with KOH along the emulsification path changing the spontaneous curvature of the interface when increasing the HLB number from 1 for the oleic acid to 20 for the potassium oleate and, therefore, changing the HLB number of the surfactant mixture. The phases diagrams are studied in order to understand the behaviour of the system and to establish the composition range where nanoemulsions can be obtained. Nanoemulsions are formed when the emulsification path crosses a region of direct or planar structure without excess of oil. Experimental design is performed in order to study the influence of composition variables as carvacrol/MCT ratio and (oleic-oleate)/Tween 80 ® ratio (OL-OT/T80 ratio) on the diameter of the nanoemulsions and their stability. It has been observed the importance of the HLB number of the surfactants mixture in order to obtain small-sized stable nanoemulsions. Surface response graphic shows that (OL-OT)/T80 ratio is a significant parameter in the mean diameter of the nanoemulsions. A minimum diameter is obtained for a (OL-OT)/T80 ratio 45/55 due to the fact that ratio is near the preferred HLB of the oil mixture and the emulsification path contains a wide liquid crystal monophasic region with all the oil incorporated in the structure. Diameters of 19 nm for carvacrol/MCT ratio of 30/70 or diameters of 30 nm for ratios of 45/55 with high stability values presented a good potential to be incorporated into edible films in the future. Regarding nanoemulsions stability an optimum value is also observed for a carvacrol/MCT ratio. The addition of another carrier oil as olive oil instead of MCT showed an improvement of the nanoemulsions stability against Ostwald ripening, probably due to the smaller solubility of olive oil. The use of olive oil does not significantly change the diameter of the nanoemulsion.

Facile modification of nanochitin in aqueous media for stabilizing tea tree oil based Pickering emulsion with prolonged antibacterial performance

Nanochitins have been explored for preparing Pickering Emulsions, however its application is restricted by its simplex disperse nature. It was hypothesized that zwitterionic nanochitins should be capable of stabilizing oil/water (O/W) interfaces in wider pH range. Furthermore, the control of their size, disperse nature and self-assembly performance suggest the formulation of tunable emulsions. Zwitterionic nanochitins were prepared via Schiff base reaction. A systematic study was performed analyzing the disperse nature, fibril morphology, surface characteristic of modified nanochitins. Oil-in-Water Pickering Emulsions stabilized by modified nanochitins were formulated and emulsion stability was analyzed as function of concentration, pH and self-assembly property and further applied for prolonged antibacterial applications. Comparing freshly prepared nanochitins, neutral/alkaline stably dispersed nanochitins can be prepared while maintaining fibril characteristics such as fibril size, crystallinity, thermal stability and so on. Better suspension stability of modified nanochitins under alkaline conditon together with the self assembly performance resulting from amino groups and carboxyl groups benefit the enhanced emulsion stability under nanochitins concentreation of 0.2 %. Encapsulation of tea tree oil in Pickering Emulsions prolongs the diffusion rate oil in the aqueous environment, thus resulting prolongs its antibacterial performance against E. coli and B. subtilis.

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.

Efficient binding paradigm of protein and polysaccharide: Preparation of isolated soy protein-chitosan quaternary ammonium salt complex system and exploration of its emulsification potential

Soy protein isolate (SPI) has good emulsifying ability, but is greatly affected by the environment. The addition of polysaccharides either increases or decreases the stability of SPI. We report and prepared for the first time SPI/HACC complexes with different polysaccharide contents (SPI/HACC ratios are 1:1, 2:1 and 5:1). The binding properties, microstructure and emulsifying properties of the SPI/HACC complexes were determined and analyzed. The results showed that the interaction them is mainly through hydrogen bonding, electrostatic interaction, hydrophobic interaction and steric hindrance effect. The combination of SPI and HACC overcomes their respective limitations and the microstructure is more flat and smooth. It was also found that the emulsifying ability and concentration of SPI showed a certain correlation and the addition of HACC significantly improved the emulsifying ability and storage stability of SPI. This study shows that the prepared SPI/HACC complex has great potential for application in the food industry.

Stability and bioactivity evaluation of black pepper essential oil nanoemulsion

Black pepper essential oil has the same disadvantages as other plant essential oils, such as volatilization, high sensitivity to light and heat and poor water solubility, which leads to great limitations in application. This study improved the stability and antibacterial properties of black pepper essential oil (BPEO) based on a nano-emulsification process. Tween 80 was selected as the emulsifier to prepare the BPEO nanoemulsion. Gas chromatograph - mass spectrometer (GC-MS) was used to analyze the composition of BPEO, of which d-limonene was the main component (37.41%). After emulsification, black pepper nanoemulsion was obtained (droplet size was 11.8 nm). The water solubility and stability of the emulsions at 25 °C were also improved with decreasing particle size. Antimicrobial properties of plant pathogens (Colletotrichum gloeosporioides, Botryodiplodia theobromae) and foodborne pathogens (Staphylococcus aureus, Escherichia coli) were evaluated by disk diffusion and other techniques for determining minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). With 12.5 mg mL^-1 MIC and 25 mg mL^-1 MBC, BPEO inhibited the growth of two tested plant pathogens and two foodborne pathogens. Essential oils (EO) were encapsulated in a nanoemulsion system to enhance the bacteriostatic effect of essential oils and reduce MIC and MBC concentrations. After emulsification, the biological activity (antimicrobial and antioxidant) of the BPEO nanoemulsion was considerably improved, nano-emulsification had certain significance for the study of EOs.

Chitosan based encapsulation of Valeriana officinalis essential oil as edible coating for inhibition of fungi and aflatoxin B1 contamination, nutritional quality improvement, and shelf life extension of Citrus sinensis fruits

In this study, a novel chitosan nanoemulsion coating embedded with Valeriana officinalis essential oil (Ne-VOEO) was synthesized in order to improve the postharvest quality of Citrus sinensis fruits against infesting fungi, and aflatoxin B₁ (AFB₁) mediated nutritional deterioration. The developed nanoemulsion was characterized through SEM, FTIR, XRD, and DLS analyses. The nanoemulsion showed controlled delivery of VOEO responsible for effective inhibition of Aspergillus flavus, A. niger, A. versicolor, Penicillium italicum, and Fusarium oxysporum growth at 6.5, 5.0, 4.0, 5.5, and 3.5 μL/mL, respectively and AFB₁ production at 5.0 μL/mL. The biochemical and molecular mechanism of aflatoxigenic A. flavus inhibition, and AFB₁ diminution was associated with impairment in ergosterol biosynthesis, methylglyoxal production, and stereo-spatial binding of valerianol in the cavity of Ver-1 protein. During in vivo investigation, Ne-VOEO coating potentially restrained the weight loss, and respiratory rate of C. sinensis fruits with delayed degradation of soluble solids, titrable acidity, pH, and phenolic contents along with maintenance of SOD, CAT, APX activities (p < 0.05) and sensory attributes under specific storage conditions. Based on overall findings, Ne-VOEO nanoemulsion could be recommended as green, and smart antifungal coating agent in prolonging the shelf-life of stored fruits with enhanced AFB₁ mitigation.

Mānuka Oil vs. Rosemary Oil: Antimicrobial Efficacies in Wagyu and Commercial Beef against Selected Pathogenic Microbes

Essential oils possessing antimicrobial characteristics have acquired considerable interest as an alternative to chemical preservatives in food products. This research hypothesizes that mānuka (MO) and kānuka (KO) oils may possess antimicrobial characteristics and have the potential to be used as natural preservatives for food applications. Initial experimentation was conducted to characterize MOs (with 5, 25, and 40% triketone contents), rosemary oil (RO) along with kanuka oil (KO) for their antibacterial efficacy against selected Gram-negative (Salmonella spp. and Escherichia coli), and Gram-positive (Listeria monocytogenes and Staphylococcus aureus) bacteria through disc diffusion and broth dilution assays. All MOs showed a higher antimicrobial effect against L. monocytogenes and S. aureus with a minimum inhibitory concentration below 0.04%, compared with KO (0.63%) and RO (2.5%). In chemical composition, α-pinene in KO, 1, 8 cineole in RO, calamenene, and leptospermone in MO were the major compounds, confirmed through Gas-chromatography-mass spectrometry analysis. Further, the antimicrobial effect of MO and RO in vacuum-packed beef pastes prepared from New Zealand commercial breed (3% fat) and wagyu (12% fat) beef tenderloins during 16 days of refrigerated storage was compared with sodium nitrate (SN) and control (without added oil). In both meat types, compared with the SN-treated and control samples, lower growth of L. monocytogenes and S. aureus in MO- and RO- treated samples was observed. However, for Salmonella and E. coli, RO treatment inhibited microbial growth most effectively. The results suggest the potential use of MO as a partial replacement for synthetic preservatives like sodium nitrate in meats, especially against L. monocytogenes and S. aureus.

Effect of Gliding Arc Plasma Jet on the Mycobiota and Deoxynivalenol Levels in Naturally Contaminated Barley Grains

Fusarium graminearum and Fusarium meridionale are primary contaminants of barley, capable of producing several mycotoxins, mainly type B trichothecenes and zearalenone. Cold plasma decontamination has been gaining prominence, seeking to control the fungal and mycotoxin contamination of food and feed and to improve product quality. To reach this objective, the present study was divided into two parts. In the first part, F. meridionale and F. graminearum strains were exposed to gliding arc plasma jet (GAPJ). Cell viability tests showed the inactivation of F. meridionale after 15-min treatment, whereas F. graminearum showed to be resistant. In the second part, barley grains were treated by GAPJ for 10, 20, and 30 min, demonstrating a reduction of about 2 log CFU/g of the barley's mycobiota, composed of yeasts, strains belonging to the F. graminearum species complex, Alternaria, and Aspergillus. A decrease in DON levels (up to 89%) was observed after exposure for 20 min. However, an increase in the toxin Deoxynivalenol-3-glucoside (D3G) was observed in barley grains, indicating a conversion of DON to D3G.

Novel approach for the inhibition of Helicobacter pylori contamination in yogurt using selected probiotics combined with eugenol and cinnamaldehyde nanoemulsions

Different strains of probiotics were screened in vitro to select the one with the highest anti-H. pylori activity. Three nanoemulsions of eugenol, cinnamaldehyde and their mixture were fabricated and tested also in vitro against the same pathogen. The selected probiotic strains, the nanoemulsion mixture and their combination were imbedded in a lab-manufactured yogurt which is deliberately contaminated with 6.0 log cfu/g H. pylori during manufacture. The inhibitory activity of all treatments on the growth of H. pylori and the other microorganisms in yogurt was evaluated during 21 days. Combining the selected probiotic strains with the nanoemulsion mixture in the contaminated yogurt reduced the count of H. pylori by 3.9 log cycle. The nanoemulsion showed lower inhibitory effect against the other microorganisms like probiotics, starter culture and total bacterial count in the tested yogurt, where their enumeration did not fall below 10⁶ cfu/g at the end of yogurt storage period.