Incorporation Of Essential Oils Research Articles

Antifungal and plasticization effects of carvacrol in biodegradable poly(lactic acid) and poly(butylene adipate terephthalate) blend films for bakery packaging

Incorporation of essential oils in biodegradable polymers produces functional sustainable packaging materials that can extend the shelf-life of foods through enhanced antimicrobial capacity. Carvacrol was incorporated in poly(lactic acid) (PLA) and poly(butylene adipate terephthalate) (PBAT) blends at different polymer proportions (30–70%) by extrusion film blowing. Biodegradable films were characterized for morphology, thermal transition and mechanical and barrier properties. Stronger mechanical relaxation in PLA indicated plasticization effects of carvacrol, giving reduced relaxation temperature with enhanced exposure of PLA as a dispersed phase in PBAT matrices and improved compatibility. Polymer-polymer and polymer-carvacrol interactions involving C=O carbonyl bonds contributed to more homogeneous microstructures. Carvacrol plasticized films had dense matrices with increased crystalline fraction of PLA that reduced permeation of vapor and oxygen. Release rates of volatile carvacrol were enhanced in lower PLA matrices, while films showed delayed fungal growth and sporulation of Penicillium sp. and Rhizopus sp., with 2.0–2.3 times increased shelf-life of packaged bread and butter cake. Films containing plasticized carvacrol showed enhanced antifungal capacity, while PLA/PBAT blend ratios controlled the strength, permeability and release behavior of carvacrol.

Biodegradable Poly(lactic acid) Stabilized Nanoemulsions for the Treatment of Multidrug-Resistant Bacterial Biofilms.

Biofilm infections caused by multidrug-resistant (MDR) bacteria are an urgent global health threat. Incorporation of natural essential oils into biodegradable oil-in-water cross-linked polymeric nanoemulsions (X-NEs) provides effective eradication of MDR bacterial biofilms. The X-NE platform combines the degradability of functionalized poly(lactic acid) polymers with the antimicrobial activity of carvacrol (from oregano oil). These X-NEs exhibited effective penetration and killing of biofilms formed by pathogenic bacteria. Biofilm-fibroblast coculture models demonstrate that X-NEs selectively eliminate bacteria without harming mammalian cells, making them promising candidates for antibiofilm therapeutics.

Essential oils as multifunctional additives in biodegradable linear low density polyethylene/starch blends

PurposeThis study aims to develop a biodegradable linear low-density polyethylene (LLDPE)/starch blends with improved mechanical and flow characteristics and evaluate the probability of using essential oils such as Moringa oleifira and castor oils as green plasticizers and compatibilizers to avoid using harmful chemicals.Design/methodology/approachCorn starch was blended with LLDPE through the melt blending technique. The corn starch content was varied from 5 to 40 phr in LLDPE. To enhance poor mechanical characteristic of the LLDPE/starch, essential oils such as M. oleifira and castor oils were incorporated into the composites with different concentrations starting from 1 to 7 phr. The essential oils’ effect on mechanical, flow character, thermal stability and electrical properties of the LLDPE/starch was also investigated. The morphology of LLDPE/starch containing essential oils was also investigated by scanning electron microscope (SEM).FindingsThe results revealed that increasing the corn starch content had an adverse effect on mechanical and flow characteristics of the composites, whereas incorporation of essential oils had increased the flow and mechanical characteristics of the composites. Also, dielectric measurements revealed that permittivity and dielectric loss increased by increasing oil content. Moreover, the values of the blends containing castor oil are higher compared to that containing M. oleifira. The SEM micrographs illustrated that the presence of essential oils in LLDPE/starch enhanced the distribution and the homogeneity of the composites, and the particle size of starch granules became smaller in LLDPE matrix.Originality/valueThis study aims to introduce green plasticizer and compatibilizer to avoid using harmful chemicals in packaging industry.

Alginate-Assisted Lemongrass (Cymbopogon nardus) Essential Oil Dispersions for Antifungal Activity.

The use of natural compounds as food preservatives is becoming increasingly popular as it is perceived positively by consumers. Among these substances, essential oils have attracted great interest owing to their antioxidant and antimicrobial properties. However, several challenges impair the use of essential oils in food products, such as their degradation or loss during food processing and storage, the strong aroma, even at low concentrations, which may negatively affect the sensory characteristics of food. In this context, the development of nanoformulations able to stabilize essential oils may represent a smart solution to this issue. The aim of the study was to evaluate the efficiency of alginate-based nanoformulations enriched with lemongrass (Cymbopogon nardus) essential oil (LEO) and Tween 80 against several fungi namely Penicillium expansus, Aspergillus niger and Rhizopus spp. Firstly, the flow behavior of systems at different concentrations of alginate (1%, 2% and 3% w/w) were studied. Then, emulsion-based nanoformulations at different concentrations of lemongrass essential oil in the range of 0–2% w/w were stabilized by a fixed amount of Tween 80, characterized and tested for their antifungal activity. Our results showed that the best nanoformulation able to inhibit Rhizopus spp., Penicillium expansum and Aspergillus niger, for at least 10 days, was constituted by 1% alginate/1.5% LEO/1% Tween 80. Hence, the incorporation of essential oil into nanoformulation systems may represent a valid alternative to overcome the disadvantages that limit the commercial application of essential oils.

Characterization of seaweed polysaccharide-based bilayer films containing essential oils with antibacterial activity

The antibacterial seaweed polysaccharide-based bilayer films were developed, which consisted of sodium alginate and agar, and incorporated with six different essential oils (EOs). The effect of different EOs on the bilayer film properties was extensively investigated based on the antimicrobial activity, the physical, mechanical and microstructure properties of the films. Addition of EOs significantly enhanced the thickness and elongation at break of the films, while decreased the tensile strength. The bilayer film containing ginger EO exhibited obvious and longer-lasting antimicrobial activity compared to films contained other EOs. It was also proved that the ginger EO film exhibit the most uniform porous structure and high crystallinity by the SEM and X-ray diffraction. Although the incorporation of EOs reduced the thermal stability of films, the better maintenance effect of ginger EO to the thermal stability of the ginger EO film was observed. According to ginger EO contained plentiful monocyclic sesquiterpenoids (71.01%) with conjugation structures, ginger EO molecules would combine with sodium alginate-agar through the p-π conjugation. Thus, the functional properties revealed that ginger EO was more positive to the comprehensive performance of films, and the sodium alginate-agar bilayer film contained ginger EO exhibited a strong potential of use in food packaging.

Effects of Plasticizer and Cinnamon Essential Oil Incorporation on Mechanical and Water Barrier Properties of Semirefined Iota-Carrageenan-based Edible Film

Iota-carrageenan, a water-soluble polymer extracted from red seaweed, Eucheuma denticulatum, showed a high potentiality as a film-forming material. Whilst, one of the essential oils that gained increasing attention is from cinnamon because of its recently observed antimicrobial and antioxidant properties. In this study, mechanical and water barrier properties of semi-refined iota-carrageenan (SRiC)-based edible film incorporated with cinnamon essential oil were evaluated into two stages. Firstly, the effects of sorbitol plasticizer’s concentration (0.5%, 1.0%, 1.5% v/v) on the mechanical and water barrier properties of the SRiC-based edible film (2% w/v) was investigated, and secondly, those of cinnamon essential oil’s incorporation (0.5%, 0.75%, and 1.0% v/v) were evaluated. SRiC (2% w/v) produced with 0.5% (v/v) sorbitol plasticizer addition was selected for the first stage, and 1% (v/v) cinnamon essential oil incorporation on SRiC-based edible film was recommended for the second, suggesting its further utilization in food application.

Incorporation of essential oils in Iranian traditional animal oil: an assessment of physicochemical and sensory assessment

This study aimed to incorporate the herbal essential oils (Ziziphora tenuior L. (Z. tenuior), Ferulago angulata (F. angulata), and Bunium persicum (B. persicum)) all in three levels (5, 7, and 10% w/w) and tertiary butyl hydroquinone (100, 200, and 300 ppm) to evaluate the oxidation stability of Iranian animal oil (IAO). Z. tenuior, F. angulata, and B. persicum (5, 7, and 10% w/w) and tertiary butyl hydroquinone (100, 200, and 300 ppm) were added to IAO. The physicochemical properties and color analysis, and sensory characteristics (odor, taste, rancidity, and overall acceptability) of the treatments were investigated on days 0, 7, 14, 21, and 28. The results showed that increasing the amounts of Z. tenuior, F. angulata, and B. persicum was associated with reducing acid, peroxide, and thiobarbituric acid values. It also lowered brightness and yellowness while the oxidative stability of the IAO significantly was increasing. It was concluded that the incorporation of B. persicum had the highest effectiveness regarding the proposed criteria with the least effect on sensory properties.

Potential of wild oregano essential oil in control of Monilinia rot on stored sweet cherry fruits

Sweet cherry fruits are perishable goods, and the fruit quality can additionally be affected by fungal diseases, primarily by Monilinia species. A promising method for fungal disease control in storage is the use of essential oils. Three different methods of wild oregano essential oil application were tested: incorporation (5% dilution), exposing to the vapor phase (0.08 and 0.16 µl/cm3), and fruit immersion in 5% dilution. Incorporation of essential oil showed the strongest inhibitory effect on Monilinia laxa in both tested cultivars (Regina and Karina). The vapor phase had the same effect on inhibition of Monilinia laxa at both concentrations on cold-stored fruits of cv. Regina after incubation at room temperature, while on cv. Karina, higher concentration showed a stronger inhibitory effect. The immersion in EO dilution caused phytotoxic changes on the fruit skin. Necrosis development rates significantly increased after the cold storage period terminated.

Incorporation of thyme essential oil into the β-cyclodextrin nanosponges: Preparation, characterization and antibacterial activity

Thyme essential oil (TEO) is a natural phenolic compound and has high antimicrobial and antioxidant activity. However, essential oils are very sensitive to environmental conditions and have high volatility and poor solubility that limit their applications. In this study, the incorporation of TEO into the β-cyclodextrin nanosponges was investigated. Diphenyl carbonate was used as cross-linker. The characterization of the obtained nanosponges was done by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), andthermogravimetric analyzer(TGA). Encapsulation efficiency, loading capacity, solubility, and antibacterial properties of the TEO-nanosponges were analyzed. The TEO-nanosponges showed porous structures with an average size lower than 326 nm. The results of FTIR and XRD confirmed the incorporation of TEO into the nanosponges. Thermogravimetric analysis indicated that the inclusion complex of TEO and nanosponges enhanced the thermal stability of TEO significantly. The inclusion complex of TEO into the nanospongesincreased its antibacterial activity. The aqueous solubility of TEO was enhanced by 15-folds after encapsulation within nanosponges. Minimum inhibitory concentration of TEO was decreased up to 29.4 folds after encapsulation into the nanosponges. The results suggest that β-cyclodextrin nanosponges can potentially be used as a delivery system for hydrophobic and sensitive compounds to increase their usage in the pharmaceutical and food industries.

Effects of incorporation of essential oil into film for fruit packaging application

Biodegradable composite films with antimicrobial properties consists of three biopolymers (polysaccharides, proteins, fats), additives (plasticizers, emulsifiers), and synthetic or natural antimicrobial. Biodegradable packaging embedded in food products with antimicrobial agent such as essential oils (EOs) is an innovative green technology based on a novel approach to substitute conventional and synthetic petroleum packaging. Good packaging is necessary to prevent spoilage during postharvest stage. Introducing EOs onto the fruit packaging films strongly inhibiting bacterial and fungal activities on the fruit products and gives positive effect on the storage of the products. This review focuses on the contribution of the incorporation of EOs and biodegradable films to prolonging the shelf life of fruit products in addition to reduce the risk of growth of pathogenic bacteria on the surface of fruit products. Essential oils incorporated into film provides a new strategy and improves efficiency of fruit packaging film in enhancing quality and shelf life of post-harvest fruit products.

Improvement of the physico-mechanical properties of antibacterial electrospun poly lactic acid nanofibers by incorporation of guar gum and thyme essential oil

The purpose of the present work was the fabrication of a novel nanofiber based on polylactic acid/guar gum (PLA/GG) containing thyme essential oil by the electrospinning method for food packaging applications. The PLA/GG nanofiber displayed smooth morphology without bead with average fiber diameter of 413.62 ± 169.73 nm. The obtained results of FT-IR and TGA analysis indicated the compatibility among PLA, GG, and thyme essential oil. Furthermore, the PLA/GG nanofibers containing 30% thyme essential oil showed high surface hydrophobicity, and suitable antioxidant and antibacterial activities. In addition, the produced nanofibers indicated no cell cytotoxicity that showed their desirable biocompatibility. As a result, the usage of PLA/GG containing 30% thyme electrospun nanofiber could be a promising system in the safety and shelf life of foods.

Effects of pectin/chitosan composite and bi-layer coatings combined with Artemisia dracunculus essential oil on the mackerel’s shelf life

This study investigated the effects of pectin coating incorporated with chitosan (CH) and Tarragon essential oil (Artemisia dracunculus) (TEO) on the microbiological, physicochemical, and sensory properties of Scomberomorus commerson muscle during refrigerated storage. The results showed that pectin coating incorporated with CH and TEO could develop active coatings with excellent antibacterial activity to inhibit bacterial growth (mesophilic, psychrotrophic, and lactic acid bacteria). The initial mesophilic, psychrotrophic, and lactic acid bacteria (log10 CFU/g) in the all samples of fillet were 3.21, 4.03 and 1.23–1.72 log10 CFU/g. Pectin-CH coating on mackerel samples enriched with TEO could retard physicochemical properties and preserve the fish quality during refrigerated storage. There was a statistical difference between composite and bi-layer coatings (CC and BC) incorporating TEO (P < 0.05). The SDS‐PAGE analysis of the samples during storage exhibited higher degradation of proteins (myosin heavy chain (MHC), paramyosin, actin, troponin T, and tropomyosin bands) in the control samples than in the treated samples. According to the quality attributes, the incorporation of essential oils or other biopolymers into edible coatings could decrease the bacterial and physicochemical deterioration of seafood during chilling.

Effects of Cornus and Its Mixture with Oregano and Thyme Essential Oils on Dairy Sheep Performance and Milk, Yoghurt and Cheese Quality under Heat Stress.

Simple SummaryVarious plant extracts have been used as feed additives to benefit ruminant performance. In this study we investigated the effects of dietary cornus plant extract supplementation, with or without the addition of oregano and thyme essential oil, in dairy ewes. Ewes participating in this experiment were reared under thermal stress and their performance, as well as the composition of their final products (milk, feta cheese and yoghurt), were assessed. The outcome of this experiment showed that cornus plant extract, alone or in combination with oregano and thyme, favored the production of ewe’s milk, along with the composition of milk and milk products.The effect of a diet supplemented with a novel cornus extract, enriched with essential oils of oregano and thyme, on the performance of Chios cross-bred dairy sheep was investigated during the summer period. The plant extracts were prepared using a “green” method based on aqueous extraction. A total of 45 lactating ewes were allocated into three equal groups in a randomized block design. The three groups were fed the same feed allowance, roughage based on Lucerne hay and wheat straw and a concentrate based on cereals and oil cakes (the control diet). The diet of two groups was fortified with cornus extract, with or without oregano and thyme essential oils, at a level 0.515 g of plant extract/essential oils per kg of concentrate. Individual milk yield was recorded weekly and feed refusals were recorded on a pen basis daily, during a six-week period of lactation. Milk samples were analyzed for the chemical composition of protein, fat, lactose and solids-not-fat constituents, somatic cell counts and total viable bacteria counts. Moreover, the milk of each group was used for yoghurt and Feta cheese production. The lipid oxidative stability, protein carbonyl content and fatty acid composition of milk, yoghurt and cheese samples were also evaluated. The results showed that the incorporation of novel plant extracts and essential oils increased the milk production per ewe. Dietary supplementation with cornus extracts and essential oils lowered lipid and protein oxidation in milk, yoghurt and cheese samples, compared to the control. However, diet supplementation with herbal extracts did not affect the fatty acid profile in milk, cheese and yoghurt or the serum biochemical parameters. In conclusion, dietary supplementation with cornus in combination with oregano and thyme has the potential to improve feed utilization and the performance of high-yield dairy Chios cross-bred ewes reared under heat stress.

Essential oils as flavoring and preservative agents: Impact on volatile profile, sensory attributes, and the oxidative stability of flavored extra virgin olive oil

This study delineates the effects of incorporation of six selected essential oils into the extra virgin olive oil (EVOO) on its volatile profile, sensory attributes, oxidative stability, fatty acid composition, and their nutritional quality. Results indicate that headspace bouquets of flavored EVOO consisted mainly on the main components of the aromatizing essential oils being carvacrol, 1,8-cineole, β-caryophyllene, trans-anethole, α-phellandrene, and limonene for thyme, rosemary, black pepper, fennel, Brazilian pepper tree, and orange, respectively. Sensory analysis showed that fennel-flavored EVOO was the most preferred by consumers. Results of 12-month storage revealed that thyme-flavored, fennel-flavored, and Brazilian pepper tree-flavored EVOO maintained good oxidative stability. Concomitantly, the content of individual fatty acid remained virtually unchanged for flavored EVOO, maintaining thereby the original nutritional quality of EVOO. The present results could open up opportunities for the development of flavored EVOO with improved oxidative stability and nutritional quality at affordable price. Novelty impact statement Essential oils can effectively be used to flavor extra virgin olive oil (EVOO). Direct incorporation of essential oils into EVOO preserves its nutritional quality, sensory attributes, and improves its oxidative stability during long-term storage. Flavored EVOO hold potential for food, pharmaceutical, and cosmeceutical applications.

Essential Oils and Their Application on Active Packaging Systems: A Review

The food industry is continuously evolving through the application of innovative tools and ingredients towards more effective, safe, natural and ecofriendly solutions to satisfy the demands of the costumers. In this context, natural sources (i.e., leaves, seeds, peels or unused pulp) can entail a valuable source of compounds, such as essential oils (EOs), with recognized antioxidant and antimicrobial properties that can be used as natural additives in packaging applications. The current trend is the incorporation of EOs into diverse kinds of biodegradable materials, such as edible films, thus developing active packaging systems with improved preservation properties that can offer benefits to both the food and packaging industry by reducing food waste and improving the management of packaging waste. EOs may be added into the packaging material as free or encapsulated molecules, where, especially this last option, has been revealed as very promising. The addition of these lipophilic compounds provides to the end-product various bioactivities of interest, which can eventually extend the shelf-life of the product by preventing food spoilage. Pairing biodegradable packaging with EOs extracted from natural agro-industrial by-products can lead to a more sustainable food industry. Recent knowledge and advances on this issue will be reviewed in the present work.

Nettle (Utrica dioica) Essential Oil Incorporation in Edible Film from Caspian Whitefish (Rutilus frisii kutum) Scale: Physical, Antimicrobial, and Morphological Characterization

ABSTRACT Byproducts from the processing of fish are a good source of gelatin. Biodegradable films including Caspian whitefish scale gelatin (CWFSG) enriched with nettle essential oil (NEO) at different levels of 0, 0.5%, 1%, and 1.5% (v/w protein) were prepared. Concerning the mechanical properties, increased concentration of NEO resulted in increased values of elongation at break and decreased values of tensile strength (TS). The incorporation of NEO at 0.5% decreased the film solubility, which then remained stable at higher concentration. This incorporation also led to an increase in water permeability, moisture content (especially at 1.5% of NEO), and turbidity. Scanning electron microscopy (SEM) images showed that the control sample had a smooth and homogenous surface, while the presence of fine cracks in the structure of edible films enriched with dose-dependent. NEO had a significant effect on the physical and mechanical changes of the edible films. CWFSG-NEO from 0.5% to 1.5% displayed an inhibitory effect in a concentration-dependent manner against Escherichia coli, Listeria monocytogenes, and Staphylococcus aureus, while no effect was observed on Pseudomonas aeruginosa. Safe and environmentally friendly CWFSG films enriched with NEO at 1% could be used as an active packaging in the food industry as an alternative to synthetic packaging.

Preparation and characterization of gellan gum-chitosan polyelectrolyte complex films with the incorporation of thyme essential oil nanoemulsion

Antimicrobial food packaging with a sustained release of antimicrobial agents plays a key role in maintaining food quality and food safety. In this study, polyelectrolyte gellan gum (GG)-chitosan (CS) multilayer film was fabricated by layer-by-layer assembly technology with the incorporation of thyme essential oil (TEO) coarse emulsion (TEOC) or nanoemulsion (TEON). The microstructure of GG-CS three-layered film was observed by scanning electron microscopy (SEM). The red fluorescent signals in confocal laser scanning microscopy (CLSM) images indicated smaller droplets and more uniform distribution of TEON prepared by ultrasonic treatments, which was consistent with the particle size results and porous structure in SEM images. The film incorporated with 6% TEON exhibited higher antimicrobial activity than that with 6% TEOC, and it significantly reduced E. coli populations in liquid model system. Moreover, films incorporated with TEON showed improved mechanical flexibility (elongation at break) and UV blocking property in comparison to TEOC. This developed GG-CS three-layered film loading with TEON was expected to be a potential antimicrobial material with sustained release property for food packaging applications.

Biberiye ve defne uçucu yağları ile zenginleştirilmiş hamsi atık protein filmlerin karakterizasyonu ve antioksidan kapasitesi

In this study, characterization and antioxidant capacity of anchovy by-product protein (ABP) films with 0.5, 1.0 and 1.5% rosemary (REO) and laurel essential oils (LEO) were investigated. The films with REO and LEO showed higher elongation at break and water vapor permeability (WVP), but lower elastic modulus, transparency, and tensile strength. L* and b* values decreased as a function of essential oil (EO) amount and films became darker and slightly yellowish. The solubility of films with REO and LEO decreased by 10.00-16.05% and 13.84-18.20%, respectively. Intermolecular interaction and molecular organization in the polymer matrix were changed by EO incorporation. Films with EOs showed a nonhomogeneous surface and comparatively smooth cross-section structure providing easy permeation. The antioxidant properties of films were enriched by addition EO and the highest antioxidant capacity was determined in 1.5% LEO film. As a result, although ABP films enriched with EOs have a high WVP, they can be used as packaging material for food products that are susceptible to lipid oxidation.

Comparative Study of Active Edible Coatings Based on Yam Starch and Cassava Starch

Aim. To compare the properties of active edible materials to active edible based on yam and cassava starch with the incorporation of essential oil of oregano (Origanum vulgare) (OEO) for application in grape coating. Materials and methods. The film-forming dispersions were obtained and the contact angle on different kinds of fruits and vegetables and the stability of the dispersions were determined. Subsequently, the films were obtained by casting, their physicochemical properties were evaluated, such as antioxidant capacity, antimicrobial capacity, among others. The grapes were covered with the best treatments and weight loss was traced and a visual inspection of their condition was carried out. Results. Remarkable differences were evident between the materials obtained from these two starch sources. The yam dispersions showed to be more stable, additionally, their films had higher moisture content, lower water absorption capacity, higher internal transmittance and slightly higher antimicrobial and antioxidant capacity. Conclusions. In the application as a coating, it was observed that the grapes coated with yam-based dispersions lost weight at a slower rate, maintaining them in good condition for a longer time, evidencing a greater potential in this type of applications compared to cassava starch.

Kinetic-thermodynamic study of the oxidative stability of Arbequina olive oils flavored with lemon verbena essential oil

Arbequina extra-virgin olive oils were flavored with lemon verbena (Aloysia citrodora) essential oil (0.1–0.4%, w/w), being evaluated quality parameters (free acidity, peroxide value, UV-extinction coefficients), oxidative stability, antioxidant and total reducing capacity. The kinetic-thermodynamic nature of the lipid oxidation was evaluated by Rancimat (110–150 °C). The essential oil addition promoted the antioxidant and total reducing capacities but, unfortunately, increased primary and secondary related quality parameters. Moreover, flavoring decreased the oils' oxidative stability. The kinetic-thermodynamic data showed that unflavored oils had significantly lower oxidation reaction rates (0.055–0.06492 h−1), more negative temperature coefficient (−0.0268°C−1), higher temperature acceleration factor (1.852), greater activation energy (82.7 kJ mol−1) and frequency factor (10.9 × 109 h−1), higher positive enthalpy of activation (79.4 kJmol-1), lower negative entropy of activation (−131.8 J mol−1K−1) and greater positive Gibbs free energy of activation (129.95–135.23 kJ mol−1), showing that oils’ oxidation was negatively influenced by the essential oil incorporation. Overall, oxidation had a non-spontaneous, endothermic and endergonic nature. Finally, olive oils could be satisfactorily classified (principal component and linear discriminant analysis) according to the flavoring level, using quality-antioxidant-stability or kinetic-thermodynamic datasets. The latter showed a less predictive performance, although ensuring the full discrimination of unflavored from flavored oils.