Search Results (185)

Essential oils (EOs) are natural mixtures of volatile compounds characterized by beneficial pharmacological effects. The repeated inhalation of EOs in olfactory training (OT) has been demonstrated to improve the sense of smell in patients with olfactory deficits. We conducted a conjunct evaluation of the chemical composition, sensory profile, and bioactivity in cell models of commercial EOs of rose (EO1), eucalyptus (EO2), lemon (EO3), and clove (EO4) used for OT (StimuScent^®, Dos Medical, Sense Trading BV, Groningen, The Netherlands). Citronellol, 1,8-cineole, limonene, and eugenol emerged as the most abundant volatile compounds in EO1, EO2, EO3, and EO4, respectively, by GC-MS analysis. Some differences emerged (using a Likert-type scale) in the perception of EO’s odor dimensions (pleasantness, intensity, and familiarity in subjects with hyposmia (n = 8) compared to controls (n = 22). Cytotoxicity assays (24 h of incubation) demonstrated the anticancer effects of EOs (5–100 μg/mL) on SH-SY5Y neuroblastoma cells (the order of potency was EO3 > EO4 > EO2 > EO1), while all EOs showed lower effects on the viability/morphology of human skin HaCaT keratinocytes. SH-SY5Y cancer cells grown for six days with different EOs (at 50 μg/mL) showed evident signs of toxicity and apoptosis. Marked changes in cell morphology (structure/number of processes) were evidenced in clove EO-treated cells. EO’s sensory properties/bioactivity were also related to the in silico physicochemical/pharmacokinetic properties of the main EO components. Our results provide new insights into a more targeted EO application for OT. Full article

This study aimed to develop a novel cream formulation incorporating pectin-based microcapsules loaded with lemon essential oil (LEO), with the goal of enhancing both sensory attributes and microbiological quality. The capsules were added at increasing concentrations (0%, 0.25%, 0.5%, 0.75%, and 1%) to assess their impact. Physicochemical analysis revealed that higher capsule content significantly improved consistency and viscosity. Microbiological evaluations confirmed the absence of key foodborne pathogens, including Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, and Enterobacteriaceae, in all formulations. Additionally, the antibacterial efficacy of the encapsulated LEO was validated against Escherichia coli and Staphylococcus aureus strains. Sensory analysis using paired comparison, ranking, and hedonic tests demonstrated a clear preference for samples enriched with the 0.5% and 0.75% capsules, noted for their enhanced creaminess, pleasant lemon aroma, and well-balanced flavour. Statistical analysis (ANOVA and principal component analysis, PCA) confirmed significant differences among samples, particularly in texture and aroma attributes. These findings highlight the potential of LEO-loaded pectin capsules as a clean-label strategy to improve both the sensory appeal and microbial safety of cream formulations. Full article

This research analyzes the innovative development of carnauba wax coatings enriched with essential oils (EOs: lemon, orange, grapefruit, clove, oregano, and cinnamon) or fruit by-products (FBPs: avocado, tomato, carrot, orange, lemon, and grapefruit) to improve postharvest preservation of organic oranges and lemons. Six EOs and six FBPs were evaluated for total phenolic content (TPC) and in vitro antifungal activity against Penicillium digitatum. Based on results, grapefruit, oregano, and clove EOs were selected for lemons, while avocado, orange, and grapefruit FBPs were selected for oranges. An in vivo test at 20 °C for 15 days with carnauba wax coatings assessed antifungal performance. Clove EO and avocado FBP showed strong in vitro inhibition and consistent hyphal suppression (~100 and ~82%, respectively). In vivo, coatings with grapefruit EO and avocado FBP significantly reduced fungal decay and sporulation (~75%) in lemons and oranges, respectively. Coated fruits also retained weight losses by ~25% compared to uncoated ones. These findings suggest that phenolic-rich natural extracts, especially from agro-industrial residues like avocado peels, offer a promising and sustainable strategy for postharvest citrus disease control. Further studies should test coating effectiveness in large-scale trials under refrigeration combined with other preservation strategies. Full article

Melissa officinalis L. (Lamiaceae) is a perennial plant species widely used in the pharmaceutical and food industries, particularly valued for its sedative properties. This study investigates the impact of synthetic mulch film and planting density as two experimental factors on agronomic performance, raw material quality, and economic efficiency in lemon balm production. The experiment was conducted at three locations in Serbia (L1: Bačko Novo Selo, L2: Bavanište, L3: Vilandrica) from 2022 to 2024, using two planting densities on synthetic mulch film (F1: 8.3 plants m⁻²; F2: 11.4 plants m⁻²) and a control treatment without mulch (C). The synthetic mulch film used was a synthetic black polypropylene film (Agritela Black, 90 g/m²), uniformly applied in strips across the cultivation area, covering approximately 78% of the soil surface. The results showed consistent increases in morphological parameters and yield across the years. Plant height in F1 and F2 treatments ranged from 65 to 75 cm, while in the control it reached up to 50 cm (2022–2024). Fresh biomass yield varied from 13.4 g per plant (C) to 378.08 g per plant (F2), and dry biomass yield from 60.3 g (C) to 125.4 g (F2). The highest essential oil content was observed in F2 (1.2% in 2022), while the control remained at 0.8%. The F2 treatment achieved complete weed suppression throughout the experiment without the use of herbicides, demonstrating both agronomic and ecological advantages. Economic evaluation revealed that F2 generated the highest cumulative profit (€142,164.5) compared to the control (€65,555.3). Despite higher initial investment, F2 had the most favorable cost–benefit ratio in the long term. This study highlights the crucial influence of mulching and planting density on optimizing lemon balm production across diverse climatic and soil conditions, while also underscoring the importance of sustainable, non-chemical weed management strategies in lemon balm cultivation. Full article

Lemon catnip (Nepeta cataria var. citriodora) is an underutilized aromatic and medicinal plant known for its high essential oil yield and distinctive lemon-like scent, and is widely used in the pharmaceutical, cosmetic, food, and biopesticide industries. Unlike typical catnip, it lacks nepetalactones and is rich in terpene alcohols, such as nerol and geraniol, making it a promising substitute for lemon balm. Despite its diverse applications, little attention has been paid to the valorization of byproducts from essential oil distillation, such as hydrolates and their secondary recovery oils. This study aimed to thoroughly analyze the volatile compound profiles of the essential oil from Lemon catnip and the recovery oil derived from its hydrolate over three consecutive growing seasons, with particular emphasis on how temperature and precipitation influence the major volatile constituents. The essential oil was obtained via semi-industrial steam distillation, producing hydrolate as a byproduct, which was then further processed using a Likens–Nickerson apparatus to extract the recovery oil, also known as secondary oil. Both essential and recovery oils were predominantly composed of terpene alcohols, with nerol (47.5–52.3% in essential oils; 43.5–54.3% in recovery oils) and geraniol (25.2–27.9% in essential oils; 29.4–32.6% in recovery oils) as the primary components. While sesquiterpene hydrocarbons were mostly confined to the essential oil, the recovery oil was distinguished by a higher presence of monooxygenated and more hydrophilic terpenes. Over the three-year period, elevated temperatures led to increased levels of geraniol, geranial, neral, and citronellal in both oils, whereas cooler conditions favored the accumulation of nerol and linalool, especially in the recovery oils. Higher precipitation was associated with elevated concentrations of nerol and linalool but decreased levels of geraniol, geranial, and neral, possibly due to dilution or degradation processes. 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

Essential oils (EOs) represent natural bioactive agents with broad applications; however, their industrial utilization is often hampered by inherent volatility and instability, which current encapsulation methods struggle to overcome due to limitations such as reliance on synthetic surfactants. Proteins, owing to their amphiphilic nature, serve as materials for EOs microencapsulation, particularly when chemically modified. Building upon our previous work demonstrating improved emulsifying properties of hemp seed protein isolate (HPI) through covalent modification with gallic acid (GA), this study investigated its efficacy for essential oil encapsulation. This study developed a novel microencapsulation system utilizing conjugates of HPI and GA for stabilizing six essential oils (lemon, grapefruit, camellia, fragrans, oregano, and mustard). The microcapsules exhibited encapsulation efficiencies (EE) ranging from 40% to 88%, with oregano oil demonstrating superior performance due to carvacrol’s amphiphilic surfactant properties. Advanced characterization techniques revealed that high-EE microcapsules displayed compact morphologies, enhanced thermal stability, and reduced surface oil localization. Release kinetics followed either the Peppas or Weibull model, with oregano microcapsules achieving sustained release via matrix erosion mechanisms. Antioxidant assays and antimicrobial tests demonstrated multifunctional efficacy, where oregano microcapsules exhibited the highest radical scavenging and antimicrobial activity. These findings establish HPI-GA conjugates as unique dual-functional emulsifier-encapsulants, offering a sustainable and effective platform to enhance EO stability and bioactivity, particularly for applications in food preservation and pharmaceutical formulations. Full article

Corymbia citriodora is a eucalypt tree of significant economic value due to its essential oils (EOs), rich in citronellal, citronellol, and other oxygenated monoterpenes with diverse biological activities. Its EOs show potential for the formulation of biopesticides with a lower impact on the environment and human health. This study evaluated the in vitro nematicidal activity of C. citriodora EOs, obtained from in vivo and in vitro grown plants, and their main volatile compounds against the pinewood nematode (PWN, Bursaphelenchus xylophilus), a major phytosanitary threat. The impact of their main compounds on the environment and human health was assessed using available experimental data and predictions from specialized software. Citronellal and citronellol were the most active EO compounds and exhibited EC₅₀ values comparable to the pesticide emamectin benzoate (0.364 ± 0.009 mg/mL). They also displayed superior safety profiles, with reduced environmental persistence and toxicity to non-target organisms. Furthermore, C. citriodora shoots were efficiently propagated through an in vitro system and their volatile profile was characterized by a dominance of citronellal (64%), and citronellol (10%), which highlights their potential as a scalable and sustainable source of nematicidal compounds. Remarkably, the EO of C. citriodora in vitro shoots was strongly active against the PWN, exhibiting the lowest EC₅₀ (0.239 ± 0.002 mg/mL) obtained. These findings underline the viability of C. citriodora EOs as a promising alternative for sustainable pest management, addressing the urgent need for environmentally friendly and health-conscious biopesticides while providing a renewable approach to nematode control. Full article

Listeria monocytogenes is a foodborne pathogen with a high tolerance to a wide range of environmental conditions, making its control in the food chain a particular challenge. Essential oils have recently been considered as potential antilisterial agents. In this study, the antilisterial effects of 57 EOs were tested on 13 different L. monocytogenes. Thirty-seven EOs were found to be effective in a strain and temperature-dependent manner. At 37 °C, all EOs were effective against at least one strain of L. monocytogenes. However, at 14 °C and 23 °C, 12 EOs, such as Minth, Nutmeg, Neroli, Pepperminth, etc., became drastically ineffective. The efficacy of the EOs increased at the lowest temperature, as only four EOs, such as Dill seed, Juniper, lemon eucalyptus, and sandalwood, were found to be ineffective at 4 °C. Ajowan and thyme were the only EOs that were antibacterial against each strain at all temperatures tested (4, 14, 23, 37 °C). Biofilm-inhibition tests with 57 EOs, performed on polystyrene plates with different surface qualities and stainless steel, using 0.1% and 0.5% final concentrations, showed the outstanding inhibitory abilities of ajowan, geranium, Lime oil, melissa, palmarosa, rose geranium, sandalwood, and thyme. Fennel, lemon eucalyptus, and chamomile had the potential to inhibit biofilm formation without affecting live bacterial cell counts. Ajowan, geranium, thyme, and palmarosa reduced the biofilm to the optical density of 0.0–0.08, OD: 0.0–0.075, 0.0–0.072, and 0.0–0.04, respectively, compared to the bacterium control 0.085–0.45. The mature antibiofilm eradication ability of the EOs revealed the outstanding features of ajowan, geranium Lime, melissa, palmarosa, rose geranium, and thyme by suppressing the established biofilm to one tenth. The different sensitivities of the isolates and the temperature-dependent antilisterial effect of the tested EOs have to be taken into account if an EO-based food preservation technology is to be implemented, as several L. monocytogenes become resistant to different EOs at medium temperature ranges such as 14 °C and 23 °C. Full article

Pichia manshurica is the main spoilage fungus that causes the deterioration of paocai. Our previous study found that the compound essential oils (CEOs) of lemon, lemongrass, and nutmeg had a good inhibitory effect; however, the antimicrobial mechanism was unknown. In order to elucidate the mechanism of action of the CEO in inhibiting P. manshurica, transcriptomics and metabolomics were used for joint analysis. The results showed that the minimum inhibitory concentration (MIC) of P. manshurica was 2 µL/mL, and the combined multi omics analyses indicated that the treatment of the CEO disrupted the ABC transporters, glycophospholipid metabolism, and nucleotide metabolism of P. manshurica, leading to the disruption of the integrity of P. manshurica cell wall and cell membrane, resulting in energy and metabolic dysfunction, and ultimately achieving the effect of inhibiting P. manshurica. The results of this study provided new insights into the mechanism of P. manshurica inhibition by CEOs, and provide a reference basis for the development of food-related bacteriostatic agents by CEOs. Full article

The growing demand for natural preservatives in the food industry has highlighted the importance of essential oils (EOs), despite their limitations related to volatility and oxidative instability. This study addresses these challenges by developing pectin-based microcapsules for encapsulating lemon essential oil (LEO) using ultrasound-assisted ionotropic gelation. The EO, extracted from Citrus limon (Eureka variety), exhibited a high limonene content (56.18%) and demonstrated significant antioxidant (DPPH IC50: 28.43 ± 0.14 µg/mL; ABTS IC50: 35.01 ± 0.11 µg/mL) and antifungal activities, particularly against A. niger and Botrytis spp. Encapsulation efficiency improved to 82.3% with ultrasound pretreatment, and SEM imaging confirmed spherical, uniform capsules. When applied to fresh-cut apples, LEO-loaded capsules significantly reduced browning (browning score: 1.2 ± 0.3 vs. 2.8 ± 0.2 in control), microbial load (4.9 ± 0.2 vs. 6.5 ± 0.4 log CFU/g), and weight loss (4.2% vs. 6.4%) after 10 days of storage at 4 °C. These results underscore the potential of ultrasound-enhanced pectin encapsulation for improving EO stability and efficacy in food preservation systems. Full article

Among the numerous diseases that affect papaya (Carica papaya L.) cultivation, anthracnose, caused by a complex of fungi from the genus Colletotrichum spp., stands out, primarily due to its damage to the commercial part of the papaya, the fruit, specifically the pulp. Although chemical control with synthetic molecules is the most commonly used method to combat anthracnose, it is not the most appropriate solution. The indiscriminate use of synthetic chemical products results in numerous harmful effects on the environment, the health of farmers, and the final consumers. Given these circumstances, the objective of this study was to analyze the efficacy of essential oils (EOs) from Citrus aurantium var. dulcis L., known as sweet orange, Citrus limon (L.), known as Sicilian lemon, and the major compound present in these oils, limonene, against the pathogens Colletotrichum okinawense, which cause anthracnose in papaya fruits. The percentage inhibition of mycelial growth was evaluated on the seventh day, with estimates of 50% and 90% inhibition, to compare the inhibitory effect among the fungal isolates. Chromatographic analysis revealed that sweet orange EO contains myrcene and limonene. Sicilian lemon essential oil includes myrcene, limonene, α- and β-pinene, and γ-terpinene. Both EOs and limonene exhibited activity against C. okinawense. The 50 µL/mL concentration was the most effective in inhibiting growth. The EOs and limonene showed similar IC₅₀ values, with limonene at 48 µL/mL, Sicilian lemon EO at 51 µL/mL, and sweet orange EO at 57 µL/mL. Full article

Lemon co-products are valuable due to their high dietary fibre, making them significant for valorisation. This research aimed to characterise an innovative lemon dietary fibre (LDF) obtained through integrated extraction (of essential oil, phenolic compounds (PCs), and pectin) by evaluating its chemical, physicochemical, structural, techno-functional, total phenolic content, and antioxidant and antibacterial properties. The effects of incorporating LDF (3% and 6%) into mortadella, a bologna-type sausage, on chemical, physicochemical, technological, and sensory properties were analysed. LDF exhibited a total dietary fibre content of 85.79%, mainly insoluble (52.55%). Hesperidin (89.97–894.44 mg/100 g DW) and eriocitrin (68.75–146.35 mg/100 g DW) were the major free PCs. The major bound PCs were vanillin (5.90–9.16 mg/100 g DW) and apigenin-7-O-glucoside (8.82 mg/100 g DW). This functional ingredient demonstrated antioxidant and antibacterial activity. LDF significantly influenced mortadella’s colour, texture, and mineral composition. Higher levels of LDF result in a paler colour and increased hardness and contribute to reducing sodium levels of the final product. It also decreased residual nitrite levels, although this reduction was followed by a slight increase in lipid oxidation, which remained below the rancidity threshold (≥1.0), ensuring acceptable product quality. Sensory evaluation revealed positive feedback, favouring the 3% LDF formulation. Full article

In this study, we explored the use of surface plasmon resonance (SPR) and Mach–Zehnder interferometry for detecting compounds in complex mixtures separated by supercritical fluid chromatography. Each molecule was individually injected and analyzed by supercritical fluid chromatography (SFC) in a 10% alcoholic solution. The fingerprints obtained via the sensors were then compared to the fingerprints of the same molecules present in a lemon essential oil (EO) at the same dilution. The results show a remarkable correlation between UV sensors and electronic noses (e-nose), enabling compound detection. The obtained signals are normalized and presented as radar charts to visualize the specific olfactory signatures of each molecule. The olfactory profiles of monoterpenes C₁₀H₁₆ such as α-pinene and limonene show notable differences, as do the C₁₀H₁₆O isomers (citral, geranial, and neral). Mach–Zehnder interferometry also allows for the discrimination of limonene enantiomers, a challenging task for current chromatography techniques. Statistical analysis confirms the ability of these technologies to differentiate compounds, including isomers. Even if UV detection is more sensitive than SPR, e-noses (SPR and Mach–Zehnder interferometers) offer the unique advantage of providing specific signatures for each compound, facilitating real-time identification. This study demonstrates the effectiveness of combining e-noses with SFC for rapid, non-destructive detection of volatile compounds. This concept can be extended to other terpenoids and volatile compounds, and hybridization with gas chromatography could be a future potential development. Full article

The drying temperature is one of the main factors affecting the storage of medicinal and aromatic plants (MAPs). The present study aimed to investigate the impact of different drying temperatures (20, 35, 42, and 49 °C) on Mentha officinalis quality attributes (moisture content, color, chlorophyll content) and the composition of its essential oil (EO), as well as the environmental impact, to determine the optimum drying temperature for this herb. According to the current findings, higher temperatures resulted in shorter drying times. However, this was accompanied by increased energy consumption and higher carbon footprint per hour of operation. Both room temperature (20 °C) and high oven temperature (49 °C) led to a darker colored product (i.e., higher browning index). Drying at 20 °C resulted in a higher EO yield compared to drying at higher temperatures (42 and 49 °C). Furthermore, lower temperatures (20 and 35 °C) and the highest temperature (49 °C) significantly decreased the levels of the two major EO compounds (geranial and neral), whereas both compounds were found in higher levels when the plants were dried at 42 °C. On the other hand, plants dried at 42 °C appeared to have the lowest amount of citronellal, significantly lower than those dried at the other tested temperatures. The results suggest that the optimum temperature for drying M. officinalis is at 42 °C, as it maintained the quality attributes of the dried product while also resulting in high quality EO. Full article