Search Results (187)

In the present work, the antimicrobial efficacy of Thymus vulgaris essential oil (EO) was investigated on Alternaria alternata strain BNR; a paper biodeteriogen was used as a model for a contaminated library. The influence of EO volume and diffusion modality, treatment duration, and inoculum age was evaluated in the vapor phase. In Petri dish screening, the influence of different EO volumes (5, 7.5, and 10 μL) on the microbial growth lag phase was investigated, and the growth inhibition period was established. The most effective treatment (10 μL EO) was then scaled up in a glass airtight container of 2650 cm³; a cold diffusion method was applied in order to quickly reach the maximum concentration of active compounds in the vapor phase. These tests demonstrated that EO efficacy is affected by the inoculum age and the contact time, and that the treatment should be performed as early as is feasible. A mycostatic effect was confirmed to be proportional to the utilized EO volume and independent from the treatment method. The information obtained in the present work will be applied to the set-up of an EO treatment in a library characterized by different levels of air contamination. Full article

Νatural compounds such as lactic, acetic, formic, and oxalic acid and thymol are currently registered for use against Varroa destructor in apiaries in Europe. Complex botanical extracts are yet to be authorized, despite their beneficial ecofriendly profile and advantages in terms of resistance management. This study examined the fumigant activity of the essential oil (EO) of oregano, clove, lavender, dittany, bay laurel, sweet orange, peppermint, blue gum, and lemon balm against V. destructor in laboratory bioassays (Petri dishes). The most effective EOs were those of Origanum vulgare, Syzygium aromaticum, and Origanum dictamnus. These three EOs yielded 33.75% carvacrol, 58.64% eugenol, and 69.77% carvacrol and exhibited significant activity from 18 h of exposure to 0.0013 μL/cm until 48 h of exposure to 0.0068 μL/cm³. Origanum vulgare’s first calculated LC₅₀ value was 0.003 μL/cm³ after 24 h of mites’ exposure to EO vapors. The LC₅₀ values stabilized for oregano, clove, and dittany at 0.001, 0.002, and 0.002 μL/cm³ of 24 h exposure, respectively. This first indication of fumigant miticidal activity in Petri dishes is a promising first step before scaling up to field experiments. Full article

Carboxymethyl chitosan (CMCS) exhibits excellent film-forming capability but suffers from limited water resistance. To enhance hydrophobicity and antimicrobial properties, citrus essential oil was emulsified directly with citrus pectin and dispersed into the CMCS matrix. This study investigated the effects of varying emulsion concentrations (0, 1, 3, 5, and 7 wt%) on film performance. FT-IR, XRD, and SEM analyses confirmed uniform emulsion distribution within the CMCS matrix with favorable compatibility. Increased emulsion loading improved water resistance, antioxidant activity, and antimicrobial efficacy of the CMCS-based films, with the 3% emulsion concentration achieving optimal mechanical strength (TS: 4.09 MPa, EAB: 144.47%) and water vapor permeability (1.30 × 10⁻¹⁰ g·m·(Pa·s·m²)⁻¹). Applied to grape preservation, the films significantly delayed quality deterioration of grapes. Furthermore, by modulating the activity of enzymes involved in anthocyanin metabolism, the films could effectively extend the shelf life of grapes by suppressing the oxidative degradation of anthocyanins. Full article

The aim of this study was to produce edible films using ovine second cheese whey (SCW) powder, alone or combined with whey protein isolate (WPI). SCW is a by-product obtained in the manufacture of ovine whey cheeses. In this instance, it was dehydrated after increasing the protein concentration by ultrafiltration/diafiltration. Furthermore, the effects of the addition of oregano (Origanum compactum) essential oil (EO) in two proportions to the films produced with a mixture of SCW powder and WPI were studied. The water vapor permeability, solubility, color, opacity, antioxidant activity, and the mechanical properties of the films were determined. In addition, we determined the films’ structure, by FTIR; thermal stability, by TGA; and microstructure and crystallinity, by XRD. SCW combined with WPI can be used to prepare edible films, but their properties were found to be affected depending on the proportion of each product. The substitution of WPI by SCW caused decreases in water solubility (from 81.44 to 66.49% D.M.), modified the color and decreased tensile strength (from 1.57 to 0.17 MPa), and decreased the elongation at break (from 52.17 to 3.57%), the puncture strength (from 2.40 to 0.20 MPa) and the deformation (from 18.92 to 0.93%) of the films. EO addition to the SCW–WPI films increased the antioxidant activity of the films (from 0.97 to 2.19 mg DPPH/g). It also modified other characteristics of the films such as the water solubility and the tensile strength. Both SCW and EO incorporations influenced the secondary structure of proteins and the thermal stability, microstructure and crystallinity of the films. Full article

This research explores how varying glycerol concentrations (0–30 wt%) affect the physicochemical and mechanical characteristics of pectin films, derived from Citrus limon waste and enriched with lemon essential oil. The films were produced using the casting method. The findings show that glycerol significantly impacts film thickness, swelling behavior, water solubility, moisture content, water vapor permeability, and structural and mechanical characteristics. FTIR spectroscopy confirmed molecular interactions between glycerol and the film matrix. Notably, films with 20–30 wt% glycerol had reduced transparency. Mechanically, glycerol increased the elongation at break, enhancing flexibility, while a 5 wt% glycerol concentration optimized tensile strength. However, higher glycerol levels led to decreased tensile strength. Principal Component Analysis identified 5 wt% glycerol as optimal for balancing flexibility and structural integrity. Additionally, glycerol-plasticized films were more hydrophilic than the control. These results highlight glycerol’s crucial role as a plasticizer and the importance of precise concentration control in biodegradable film formulations. Full article

In this study, a new edible gel of Perilla essential oil (PE)/grape seed extract (GSE)–chitosan/gelatin was prepared, and it was applied to the preservation of silver carp. By establishing a fuzzy mathematical model, using a single-factor experiment and Box–Behnken response surface optimization combined with matlab analysis, the optimum preparation conditions of composite gel films were determined: the addition of PE (p < 0.01) was 6.91 μL/mL, the addition of GSE (p < 0.05) was 0.45 mg/mL, and the addition of gelatin (p > 0.05) was 1.63%. Under these conditions, the composite gel films exhibited an excellent water vapor barrier and mechanical properties. Using Fourier-transform infrared spectroscopy (FTIR) analysis, it was found that the addition of PE enhanced or weakened the absorption peaks, indicating the molecular interaction between PE and the substrate. Scanning electron microscopy (SEM) observed that the surfaces of the composite gel films with added PE were smooth, but there were a few pores in the cross-section. X-ray diffraction (XRD) analysis showed that PE had good compatibility with other components. The fresh-keeping experiment showed that the composite gel films could significantly prolong the fresh-keeping period of grass carp. After 10 days of storage at 4 °C, compared with the blank group (without plastic wrap) and the control group (with composite gel film, no PE added), the experimental group (with composite gel films, PE added) showed better fresh-keeping effect in terms of sensory score, moisture content, pH value, TBARS value, and TVB-N value (p < 0.05). Correlation analysis further confirmed the positive effects of composite gel films on water content, pH value, TVB-N, and other quality indexes of silver carp, indicating that the composite gel films will have broad application prospects in the food preservation field. This study provides an innovative basis and theoretical basis for the development and application of natural polysaccharide/protein composite edible film, which is helpful to promote the development of green food-packaging materials. Full article

Protein-based films have gained attention due to their potential as biodegradable packaging. This study investigated the properties and characteristics of film-forming emulsions (FFEs) and their films based on co-precipitated protein (CPP) from Bambara groundnut protein isolate (BGPI) and acid-soluble collagen (ASC) emulsified with different levels of basil essential oil (BE) (50%, 75% and 100%) and soy lecithin (SL) (25% and 50%). The oil droplet size, stability, and distribution of FFEs were characterized. Larger oil droplet sizes, a higher flocculation factor, and a higher coalescence index were observed for FFEs emulsified with higher levels of BE and SL. All FFEs had uniform oil distribution. Films from different FFEs were formed and analyzed. Films containing BE and SL had higher thickness, elongation at break, b*-value, water vapor and UV-light barrier properties, but a lower tensile strength than the control film. Emulsion films exhibited smooth surface and rough cross-section and were heat-sealable. FTIR spectra indicated lower protein interactions in the emulsion film containing higher levels of BE and SL. The film containing 100% BE had the highest antioxidant activities, regardless of the SL level used. The emulsification of BE and SL at various levels thus influenced the properties and characteristics of the FFE and emulsion film. Full article

Soft rotting caused by Rhizopus stolonifer is one of the most important postharvest decays in Kokei No. 14 organic sweet potato roots. While various methods have been explored for controlling this pathogen, there remains a need for effective, safe, and applicable alternatives, particularly using essential oils (EOs). This study evaluated the efficacy of EOs, specifically carvacrol, thymol, and thyme oil, in controlling Rhizopus soft rot. We conducted both in vitro and in vivo tests to assess their effects on fungal mycelial growth, spore germination, and the incidence and severity of soft rot in sweet potatoes, along with quality evaluations of the roots. The results indicated that the vapor phase of carvacrol, thymol, and thyme oil was more effective than the contact phase in inhibiting fungal growth and spore germination. In vivo tests revealed that all three EOs significantly reduced the incidence and severity of soft rot, with thymol and thyme oil at 300 mg/L, and carvacrol at 500 mg/L being the most effective. Quality assessments showed minimal impact on properties such as firmness, weight loss, color, starch, carotenoids, and flavonoids, although residual odors increased. GC/MS analysis confirmed that thyme oil contained high levels of both thymol and carvacrol, along with other antimicrobial compounds, suggesting that the cumulative activity of these volatile compounds enhanced their bacteriostatic effects. Thyme oil demonstrated greater efficacy in reducing soft rot development compared to its individual components, making it a promising biofumigant for controlling postharvest diseases in Kokei No. 14 organic sweet potato roots. These findings emphasized the potential for using thyme oil as a safe and effective approach to managing postharvest decay. Full article

The development of sustainable biodegradable packaging materials is essential for enhancing food quality and shelf life while reducing plastic waste. This study explored polymer-based monolayer, composite, and bilayer films to produce water-soluble, oil-proof pouches. Single-serving seasoning oil pouches were prepared from bilayer films with polyvinyl alcohol (PVA) as the inner and sodium alginate (SA) as the outer layer. The PVA/SA films exhibited excellent UV protection, low oil permeability (0.18 × 10⁻⁶ g·mm/mm²·day), hydrophilic surface (water contact angle < 90°), and rapid solubility in hot water (87 ± 2 °C). Incorporating curcumin, a natural antioxidant, into PVA/SA films (Cur-PVA/SA) improved thermal stability, reduced light transmittance, and decreased water vapor permeability (0.28 × 10⁻¹⁰ g/m·Pa·s). Curcumin release followed a biphasic diffusion model, with 94.8% released at 96 h (diffusion coefficient: 1.30 × 10⁻¹¹ m²/s), ensuring prolonged antioxidant activity. The Cur-PVA/SA pouches delayed lipid oxidation more effectively, with peroxide values of 6.48 and 10.35 meq/kg after 45 days at 35 °C, respectively. The Q₁₀ model, which is commonly used to predict the shelf life of oils based on temperature-dependent oxidation rates, estimated that the oil packaged in Cur-PVA/SA pouches would remain stable for 12 months at 23 °C. This represents a 37% longer shelf life compared to oil packaged in PVA/SA pouches without curcumin. Cur-PVA/SA pouches also reduced noodle moisture migration, limiting weight loss to 2.73% over 14 days compared to 5.80% in controls. These findings highlight their potential as eco-friendly active packaging solutions. Full article

We developed bio-based chitosan–gelatin films, CHG-LO films, incorporating lavender essential oil (15–26 wt% LO) and oleic acid (33–47 wt% OA) with smooth surfaces and thicknesses of 0.42–0.99 mm. For their manufacture, the nanoemulsions were prepared to possess uniform dispersion and colloidal stability with average droplet sizes of 475–854 nm, polydispersity indices (PDI) of 0.095–0.235, and zeta potentials of 23.7–56.9 mV at 40 °C, where OA served as surfactant and phase change material. The opacities of the CHG-LO films increased by 1.8 to 5.5 times compared to the control group, and their UV-visible light-blocking properties improved. These films demonstrated cyclic thermal buffering character, with heat storage capacities ranging from 14.0 to 36.0 J·g⁻¹ between −26 °C and 20 °C compatible with that of OA. Additionally, they showed reduced water vapor transmission rates and swelling degrees in acidic and neutral environments. The total phenolic contents of the CHG-LO films increased 1.5–4.2 times compared to the control associated with the presence of LO phenolic groups in the structure. DPPH (2,2-diphenyl-1 picrylhydrazyl) and ABTS (2,2′–azino–bis(3–ethylbenzothiazoline–6–sulphonic acid)) scavenging activity test results show that the antioxidant properties of these films improved with increasing LO-OA content up to 2.2 and 1.3 times the control, respectively, and also showed antimicrobial properties. The multifunctional CHG-LO films of this study are promising candidates for temperature-sensitive active packaging in food as well as in pharmaceutical and cosmetic industries. Full article

The aim of this study was to develop gelatin-based films incorporating Melaleuca alternifolia essential oil (MEO) and assess their application on refrigerated chicken breasts. The results showed that MEO exhibited antimicrobial activity against Pseudomonas aeruginosa and Salmonella sp., with inhibition zones of 17 mm and 9 mm, respectively. The minimum inhibitory concentration (MIC) was 10% for P. aeruginosa and 15% for Salmonella sp., demonstrating greater efficacy against P. aeruginosa. The antioxidant analysis using the ABTS method revealed activity of 1309 ± 18.0 μM Trolox/g, while the FRAP method resulted in 446 ± 5.78 μM FeSO₄/g. The characterization of the oil by gas chromatography identified major compounds, including 2-carene, γ-terpinene, terpine-4-ol, and α-terpineol. Incorporating the oil into gelatin films resulted in structural changes, such as an increase in thickness (from 0.059 to 0.127 mm) and water vapor permeability. Furthermore, the addition of MEO conferred homogeneous properties to the films with no visible cracks. The incorporation of MEO into gelatin films has shown ABTS antioxidant activity, and FRAP results showed a significant increase with higher MEO concentrations. The packaged samples retained more mass than the control group, which lost about 90% of its weight during storage. Texture analysis revealed only an 8% variation in the Melaleuca-coated samples compared to 19.6% in the control group. These findings indicate that gelatin films containing Melaleuca essential oil effectively improve the shelf life of chicken breasts. Full article

Background/Objectives: In recent years, antimicrobial resistance has become a major threat to global health, and scientific research aiming to identify new therapeutic resources is a priority. Essential oils (EOs), obtained from spices belonging to the culinary tradition, like Carum carvi essential oil (CC-EO), are of great interest for their antimicrobial activity, but the methods used to evaluate their efficacy need to be standardized. The aims of this work were to evaluate the following: (i) the best microbiological in vitro test; (ii) the best surfactant; and (iii) the best microbiological target of CC-EO and its method of administration. Methods: CC-EO quality was evaluated using gas chromatography–mass spectrometry. Antimicrobial susceptibility testing with drugs currently in use was performed. Antimicrobial effectiveness against 70 clinical strains belonging to S. aureus, E. coli, E. faecalis, K. pneumoniae, P. aeruginosa, S. pyogenes, and C. albicans was evaluated. Two microbial tests (broth microdilution tests and disk diffusion), generally used in routine clinical practice, were compared. To choose the best vehicle, Tween80, DMSO, and ethanol were evaluated. The antimicrobial efficacy of vapors was assessed using a microatmosphere test. Results: The broth microdilution test is confirmed as the best in evaluating the antimicrobial activity of EOs. The most suitable EOs vehicle for antimicrobial testing was Tween80. CC-EO and its vapors were effective against GRAM+ and C. albicans strains, both sensible and resistant, and ineffective against GRAM−. Conclusions: In the future, it may be possible to include CC-EO in topical or spray formulations for the treatment of GRAM+ and C. albicans infections. Full article

To address the challenges and risks associated with the declining crude yield, an optimization project for the surface production facilities at ZY Oilfield is underway. Upon the completion of this project, the oilfield’s export pipelines will transport water-containing live crude oil. To ensure pipeline transportation safety, it is essential to clarify the phase behaviors and flow state of water-containing live oil. For this purpose, the VLLE characteristics of water-containing live oil were analyzed with Aspen HYSYS V12 software and validated through PVT tests. Additionally, the pressure variations in multiphase flow pipelines under different operating conditions were calculated using the Beggs and Brill–Moody–Eaton method with Pipephase 9.6 software. The results indicated that the bubble point pressure and vapor fraction of water-containing live oil were higher than those of dehydrated dead crude within the operating temperature range. Liquid–gas flow was likely to occur in the presence of low soil temperatures, low oil output, low outlet pressure, high outlet temperatures, or small water fractions, particularly at the pipeline ends. Moreover, the optimized technological processes for stations and pipeline operations were proposed. The findings offer a new approach for the safe transportation of low-output live oil and provide valuable insights for optimizing surface production in aging oilfields. Full article

The effect on the physical, mechanical, and antibacterial properties of films composed of alginate-chitosan with the incorporation of oregano (EOO) or thyme (EOT) essential oils was evaluated. These films showed a thickness between 37.7 and 38.2 µm, with no significant differences for essential oil content. Water vapor permeability decreased from 4.03 (oil-free film) to 1.65 (g/msPa) × 10⁻⁹ in 3% EO. Mechanical properties reflected a reduction in tensile strength (TS) from 73 (oil-free films) to values between 34 and 38 MPa with 3% EO, while elongation (E%) increased from 4.8% to 10.4–11.8%. Regarding antibacterial capacity, as the concentration of essential oil increases, the antibacterial capacity also increases. On average, the increase from 1.0% to 3.0% of EOO increased the antimicrobial capacity against Gram-negative and Gram-positive bacteria. EOO outperformed EOT against E. coli and L. monocytogenes. In addition, films with 2–3% EOT showed a significant dark yellow color compared to the control. These results suggest that films with the addition of oregano and thyme essential oils can be promising for food packaging applications with the ability to improve food safety and increase product shelf life by achieving functional packaging characteristics. Full article

Eggs are considered a nutritionally complete food and an excellent source of protein. However, they are prone to bacterial contamination, which can affect their internal quality and safety. This study aimed to evaluate the effectiveness of essential oils (EOs) as natural sanitizers for eggshells to reduce the bacterial load and improve shelf life. Ten EOs—cinnamon, clove, lavender, peppermint, thyme, rosemary, green tea, mustard, basil, and marjoram—were tested for antibacterial activity against three Gram-positive bacteria (Staphylococcus aureus, Enterococcus faecalis, and Listeria monocytogenes) and three Gram-negative bacteria (Salmonella Enteritidis, Pseudomonas aeruginosa, and Escherichia coli) using the well diffusion method. The most effective EOs were assessed in vapor form using a disc volatilization technique. A total of 288 eggs from a local farm in South Lebanon were treated with selected EOs and stored at room temperature for three weeks to evaluate microbial load and quality. The eggs were grouped into six categories: dry control, ultraviolet (UV) treated, and eggs sprayed with EOs, based on the recorded minimum inhibitory concentration (MIC) values. At each time point, 12 eggs from each group were analyzed for microbiological testing and external and internal quality. Results indicated that nine of the ten EOs showed antibacterial activity, with the highest inhibition zones recorded for cinnamon against S. Enteritidis (14 mm) and E. coli (9 mm), peppermint against P. aeruginosa (10 mm), and rosemary against L. monocytogenes (22 mm), S. aureus (19 mm), and E. faecalis (12 mm). Vapor phase testing showed that rosemary, thyme, clove, and cinnamon EOs had average inhibition zones ranging from 21 to 33 mm against the tested bacteria, and peppermint EO achieved complete inhibition of P. aeruginosa. Clove EO consistently reduced the bacterial load as a sanitizer on eggs, initially achieving complete inhibition. While egg quality parameters such as weight, shell thickness, Haugh unit, and yolk color declined over time, EOs helped maintain better quality compared to dry controls. GC-MS analysis of the tested EOs revealed that monoterpene alcohols are the major constituents of most oils. This study concludes that EOs are effective natural sanitizers for eggs, enhancing safety and preserving quality during storage. Full article