•Starch films (TPS) with nanocellulose-stabilized Pickering emulsions (PE) with three different essential oils were prepared.•TPS-PE Cardamom presented low mechanical properties and limited chemical ...interaction.•TPS-PE Cinnamon has intermediate mechanical properties and low water vapor permeability (WVP).•TPS-PE-Ho wood showed excellent mechanical, thermal, and WVP properties, being potential for food application.
Consumers are increasingly demanding biodegradable food packaging with a minimal amount of synthetic preservatives and, at the same time, worried about potential contaminants, particularly during any pandemic event. Plant essential oils (EO) are natural compounds with remarkable antimicrobial properties. This study aimed to prepare thermoplastic starch films (TPS) containing nanocellulose-stabilized Pickering emulsions (PE) of different essential oils: ho wood (Cinnamomum camphora), cardamom, and cinnamon, and investigate the suitability of biopolymer films as packaging material. The films were prepared via casting method and were characterized concerning chemical interactions by FT-Raman and FTIR, mechanical, crystallinity, thermal, and water vapor permeability properties. PE Ho wood-starch films showed strong chemical interactions, which significantly improved the film's mechanical resistance. The films with cardamom and cinnamon showed low compatibility, with a decrease in tensile strength. All films showed less crystallinity than the pristine TPS, which can be attributed to the starch chain organization's changes. The films showed high thermal stability due to the strong molecular interactions among starch chains and PE, as confirmed by TGA and DSC analysis. The films' thermal stability is an indication that it can be safely applied in the food industry. Besides, the films showed a lower water vapor transmission rate, and the water may act as a carrier for PE, improving the release of the active compounds. This study reveals the differences between three essential oils incorporated into starch-based films. The ho wood films are the most promising PE to be applied as biodegradable active packaging.
In this work, the effects of cinnamon and mustard essential oils against nine foodborne bacteria were evaluated. Their antimicrobial susceptibility and action mechanism was also assessed. ...Additionally, the effects of the combination between both were evaluated. To provide data on the in vitro action of essential oils, the transfer mechanism was assessed using gas chromatography–mass spectrometry. The results indicated that the mustard presents 10 times more bactericidal/bacteriostatic effect than cinnamon essential oil. In both cases the action mechanism happened intracellularly, but since mustard induces cell cycle arrest, cinnamon produces protrusions and aggregation. The combinatorial assays demonstrated in most cases an additive effect. In addition, synergies for P. putida and E. coli OI57:H7 were shown. Therefore, to introduce them in combination, could be a great way to make a natural-active packaging. The distinct activity profiles can be explained by their transfer mechanism that involves vapour release and agar diffusion.
The industry is focused on improving food safety by controlling the growth of foodborne and food spoilage microorganisms and by reducing the use of synthetic preservatives. The novelty of this research article lies in the study of antimicrobial activity of two natural active agents (mustard and cinnamon essential oil), separately and in combination, against nine foodborne bacteria; as well as the study of its mechanism of action and transfer. The set of all outcomes give the necessary information to be able to design a novel food active packaging based on the applied microbiology studied.
•Mustard EO has 10 times more bactericidal/bacteriostatic effect than cinnamon EO.•The absence/presence of inhibition halo is related to the EO transfer mechanism.•Transfer mechanism involves EO vapour release and agar diffusion.•Synergies were shown for P. putida (bacteriostatic) and E. coli OI57:H7 (bactericide).•Mustard induces cell cycle arrest while cinnamon produces protrusions and aggregation.
Plant essential oils have excellent antioxidant and antibacterial properties, which can greatly reduce microbial resistance. However, the odor and cost issues caused by their high concentration use ...remain the main bottlenecks in their application as antibacterial agents. The present study was conducted to evaluate inhibitory activity of essential oils (EOs) against Escherichia coli and Staphylococcus aureus, and focus on synergistic activity of EOs against Malassezia furfur. The minimum inhibitory concentrations and the active components of various EOs and their combination were determined using the agar dilution method and gas chromatography–mass spectrometry, respectively. The synergistic effect of EO combination on Malassezia furfur was evaluated by analyzing its growth, morphology, and cell membrane fluidity using growth curve analyses, scanning electron microscopy, and N-phenyl-1-naphthylamine method, respectively. Additionally, the antioxidant activity of the EOs combination was evaluated using the free radical scavenging method. The mixture of EOs exerted a synergistic effect on M. furfur, causing logarithmic growth phase lag, cell damage, decreased membrane fluidity, and the mixture of EOs also had synergistic effect on DPPH free radical scavenging. Conclusively, the combination of EOs investigated in this study exhibited good antibacterial ability against M. furfur, may have potential applications in seborrheic dermatitis.
•CEO and TEO had synergistic effect on antimicrobial activities, DPPH free radical scavenging.•Escherichia coli, Staphylococcus aureus and Malassezia furfur were inhibited.•The synergistic effect reduced the required doses of essential oil.
Plants of the genus Zingiber (Family Zingiberaceae) are widely used throughout the world as food and medicinal plants. They represent very popular herbal remedies in various traditional healing ...systems; in particular, rhizome of
spp. plants has a long history of ethnobotanical uses because of a plethora of curative properties. Antimicrobial activity of rhizome essential oil has been extensively confirmed in vitro and attributed to its chemical components, mainly consisting of monoterpene and sesquiterpene hydrocarbons such as α-zingiberene, ar-curcumene, β-bisabolene and β-sesquiphellandrene. In addition, gingerols have been identified as the major active components in the fresh rhizome, whereas shogaols, dehydrated gingerol derivatives, are the predominant pungent constituents in dried rhizome.
spp. may thus represent a promising and innovative source of natural alternatives to chemical food preservatives. This approach would meet the increasing concern of consumers aware of the potential health risks associated with the conventional antimicrobial agents in food. This narrative review aims at providing a literature overview on
spp. plants, their cultivation, traditional uses, phytochemical constituents and biological activities.
Background: Treatment options for aspergillosis include amphotericin B (AMB) and azole compounds, such as itraconazole (ITZ). However, serious side effects related to these antifungal agents are ...increasingly evident, and resistance continues to increase. Currently, a new trend in drug discovery to overcome this problem is represented by natural products from plants, or their extracts. Particularly, there is a great interest in essential oils (EOs) recognized for their antimicrobial role towards bacteria, fungi and viruses. Methods: In this study, we evaluated the antifungal activity of eleven commercial EOs—clove, eucalyptus, geranium, hybrid lavender, lavender, lemon, lemongrass, neroli, oregano, tea tree and red red thyme—in comparison with AMB and ITZ against Aspergillus flavus, A. fumigatus and A. niger clinical isolates. Antifungal activity was determined by broth microdilution method, agar diffusion technique, fungistatic and fungicidal activities and vapor contact assay. Results: Gas chromatography–mass spectrometry analysis displayed two groups of distinct biosynthetical origin: monoterpenes dominated the chemical composition of the most oils. Only two aromatic compounds (eugenol 78.91% and eugenyl acetate 11.64%) have been identified as major components in clove EO. Lemongrass EO exhibits the strongest antimicrobial activity with a minimum inhibitory concentration of 0.56 mg/mL and a minimum fungicidal concentration of 2.25–4.5 mg/mL against Aspergillus spp. strains. Clove and geranium EOs were fairly effective in inhibiting Aspergillus spp. growth. Conclusions: These results demonstrate the antimicrobial potential of some EOs and support the research of new alternatives or complementary therapies based on EOs.
•Factors involved in rosemary essential oil extraction process were studied in order to identify the influence of each factor to the yield.•A Plackett-Burman design allowed to test the simultaneous ...effect of the several factors and to understand the influence of each factor on rosemary essential oil yield.•Among many factors tested, the extraction time and the extraction process are resulted the two significant factors.•The optimal range of significant factors was identified in order to maximize rosemary essential oil yield and to reduce consumption and waste.
Several factors influence the yield of rosemary essential oil obtained by steam distillation (ST) and hydro distillation (HY). This study proposes to identify and analyse them, in order to maximise essential oil yield and reducing consumptions. First, a Plackett–Burman design (PBD) was applied to test the simultaneous effect of several factors involved in the extraction process, and understand their relative influence on yield. The following factors were tested: extraction method (HY and ST), extraction time (30 min and 120 min), cooling water flow rate (1 L/m and 5 L/m), heating power (600 W and 2000 W), ratio of rosemary leaves to deionised water (solid/ liquid ratio 1:2 and 1:6). Two leaf pre-treatments were also considered: grinding and blast freezing. The PBD results identified two significant factors (extraction time and extraction method) that were subsequently validated in a full factorial experiment. Two extraction methods and four extraction times were tested. Analysis of variance results showed that maximum yield was obtained by ST with an extraction time of 120 min. Finally, chemical and physical analyses were conducted to evaluate qualitative aspects of the obtained essential oils.
•This review focuses on terpenoids extracted from essential oils.•Terpenoids have enantiomers with distinct physiological activities.•Predominant extraction methods are HD, SFME, HS-SPME and ...supercritical fluid.•2D GC is found to have stronger chiral chromatography resolution ability.•Specific distribution and enantiomer excess results could be used as quality markers.
Terpenoids possess significant physiological activities and are rich in essential oils. Some terpenoids have chiral centers and could form enantiomers with distinct physiological activities. Therefore, the extraction and separation of terpenoids enantiomers are very important and have attracted extensive attention in recent years. Meanwhile, the specific distribution and enantiomer excess results (the excess of one enantiomer over the other in a mixture of enantiomers) could be used as quality markers for illegitimate adulteration, origin identification, and exploring component variations and functional interrelations across different plant tissues. In this study, an overview of the progress in the extraction of terpenoids from essential oils and the separation of their enantiomers over the past two decades has been made. Extraction methods were retrieved by the resultant network visualization findings. The results showed that the predominant methods are hydrodistillation, solvent-free microwave extraction, headspace solid-phase microextraction and supercritical fluid extraction methods. GC–MS combined with chiral chromatography columns is commonly used for the separation of enantiomers, while 2D GC is found to have stronger resolution ability. Finally, some prospects for future research directions in the extraction and separation identification of essential oils are proposed.
•The incorporation of antioxidants led to a heterogeneous film microstructure.•The water vapour permeability of the films was only slightly improved when citric acid and α-tocopherol were added.•The ...oxygen barrier properties of the films were significantly improved in every case.•The films containing α-tocopherol showed the highest antioxidant power of all the tested compounds.•The mechanical properties of the films were barely affected by the antioxidants.
Blend edible films were prepared from wheat starch (WS) and chitosan (CH) with glycerol as plasticizer. Four active ingredients (antioxidants) were added, namely basil essential oil, thyme essential oil, citric acid and α-tocopherol. The starch:antioxidant mass ratio was 1:0.1. Prior to characterisation, the films were conditioned at 25°C–53%RH as to their structural, mechanical, optical and barrier properties. The antioxidant capacity of the active ingredients was determined by means of a spectrophotometric method. The incorporation of antioxidants led to a heterogeneous film microstructure, mainly in those containing α-tocopherol, which affected the surface roughness. Yellowness was induced in films when α-tocopherol was added and no notable colour changes were observed in the other cases, although all the antioxidants increased the transparency of the films. Despite of the fact that the mechanical properties were barely affected by the incorporation of antioxidants, citric acid promoted an increase in the elastic modulus but a decrease in film stretchability. The water vapour barrier properties of the films were only slightly improved when citric acid and α-tocopherol were added, whereas the oxygen barrier properties were significantly improved in all cases. The greatest antioxidant capacity of the films was reported for films containing α-tocopherol, which exhibited the highest antioxidant power.
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•CEO and CLO improved physical, thermal and antimicrobial properties of films.•The addition of CEO showed better thermal stability and EO retention than CLO.•Sustained release and ...enhanced antimicrobial activity were obtained as CEO% increased.•Combined EOs decreased particle size and showed synergistic antimicrobial effects.
Chitosan-gum arabic-based polyelectrolyte complexed films with cinnamon essential oil (CEO) and clove essential oil (CLO) were developed. The effect of EO concentrations, types and their combinations on the physical, thermal and antimicrobial properties of films were investigated. The results showed that the incorporation of EOs decreased the ζ-potential and viscosity, but increased the particle size of film-forming dispersions. Films incorporated with CEO and combined EOs exhibited better water barrier properties compared to those with CLO and single EO. Films containing CEO showed lower EO loss and higher thermal stability compared to those containing CLO, and the reason was attributed to the stronger interactions between chitosan, gum arabic and CEO. The combination of EOs resulted in higher retention and delayed release rate in food stimulant, resulting in stronger antimicrobial activities. The performance of films with the CEO and the combined EOs brought new formulation ideas in antimicrobial films.
A new active packaging film of bilayer structure based on low-density polyethylene (LDPE) incorporated with rosemary essential oil (REO) and cinnamon essential oil (CEO) in the inner layer has been ...designed and developed for preserving shrimp. Six types of active packaging films REO (1% w/w), REO (2% w/w), CEO (1% w/w), CEO (2% w/w), REO (1% w/w) + CEO (1% w/w) and control (film without EO) were designed by blown film extrusion method. Tensile strength (TS), water vapor transmission rate (WVTR), oxygen transmission rate (OTR), thermogravimetric analysis (TGA), and microstructure of films were investigated to justify the effect of EOs on the film physical functionality. The outcomes of scanning electron microscopy (SEM) analysis revealed that the surface of active films became relatively rougher by the incorporation of REO or CEO into the LDPE matrix. Meanwhile, the films with different amount of EOs proved to have a slight decline in the TS, whereas improved the barrier properties. In addition, shrimp packaged in active films containing EOs revealed lower microbial counts, total volatile basic nitrogen (TVB-N) contents, and thiobarbituric acid reactive substances (TBARS) values compared to samples packed in control films during storage at 4 °C for 10 days. The results indicated that the blended film (REO + CEO) showed more effective in maintaining the freshness and extending the shelf life of packaged shrimps up to 4 days. This new active packaging film has potential to be used for enhancing the quality and storage stability of aquatic products.
•A new LDPE-based active film containing REO and CEO has been developed.•Pacific white shrimp were packaged with active films under vacuum at 4 °C.•Blended film effectively retained and prolonged shrimp freshness and shelf-life.•The new film shown promise to be commercially used for food packaging applications.
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