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Characteristics of two Cedarwood essential oil emulsions and their antioxidant and antibacterial activities
Abstract
Cedarwood essential oil (CEO) has the effect of anti-inflammatory and anti-bacteria. However, the application of this essential oil is limited due to its strong volatility and poor water solubility. To address this issue, two types of oil-in-water CEO emulsions including CEO nanoemulsion (CEO-NE) and CEO Pickering emulsion (CEO-PE) were prepared. CEO-NE with 5% surfactant, had a smaller particle size (135.14 ± 1.1 nm) and higher absolute zeta potential value (32.75 mV) compared with CEO-PE (1% starch) which particle size was 626.21 ± 6.05 nm, zeta potential was 27.58 mV. The stability of CEO-NE and CEO-PE were tested by multiple light scattering, results showed that Turbiscan Stability Index (TSI) value of CEO-NE was much lower than that of CEO-PE. CEO-NE and CEO-PE exerted higher free radical scavenging activities, iron reducing power and antibacterial ability than CEO itself. These results indicated that emulsification is a feasible method to extend application of CEO.
... With the addition of 0.5 mL 5α-cholestane alcoholic solution 0.1 mg/mL as an internal standard, 0.2 g L. edodes oil was saponified, extracted, silanized, and analyzed according to the method from Kang 24 . 2.3.5 Antiradical scavenging activity DPPH radical scavenging activity, ABTS radical cation decolorization assay, and the reducing ability of ferric ions of L. edodes oil were measured based on methods reported from Nafis 29 , Huang 30 , and Zouirech 31 , respectively. ...
... L. edodes oil was found abundant in polar lipids 12.72 -24.00 , which was consistent in accordance with the fact that most mushrooms are rich in polar lipid proportion but low in neutral lipid 33 . The lipid class distributions of the four L. edodes oil samples were compared, and chloroform-extracted L. edodes oil revealed a higher percentage of glycolipids 16.70 and phospholipids 7. 30 than the other oil samples, resulting in its lower glyceride content 76 , which might be induced by similar compatibility. Therefore, based on the huge amount of polar lipid, chloroform-extracted L. edodes oil was prone to perform better emulsifying property, providing a theoretical basis for new applications of L. edodes oil. ...
... According to the score and loading plots of the first two principal components for four L. edodes oil samples in Fig. 4A, the first two principal components accounted for 87.30 PC1 ¼ 59. 30 and PC2 ¼ 28.00 of the total variation. In contrast to the distribution of chloroform-and ethyl acetate-extracted L. edodes oil, n-hexane-and petroleum ether-extracted oils were aggregated in both the second and third quartiles, indicating an extremely similar phytochemical property and free radical scavenging activity between n-hexane-and petroleum ether-extracted oils. ...
In this study, effects of 4 solvents (petroleum-ether, n-hexane, ethyl-acetate, and chloroform) on the chemical characterizations and in vitro antioxidant capacities of oil were assessed to determine the optimal extraction solvent for L. edodes oil. Three data analysis techniques including principal component analysis, hierarchical cluster analysis, and multiple linear regression, were applied to determine the relationship between the nutrient and antioxidant capacity. The results showed that chloroform extracted L. edodes oil exhibited the largest amount of α-tocopherol, flavones, and unsaponifiable matter, chloroform was thus confirmed desirable for extracting L. edodes oil rich in nutrition. While based on the best DPPH and ABTS, the ethyl-acetate extracted oil show the strongest antioxidant property. More than that, the results also showed that different extraction solvents could induce large variations in minor components and free radical scavenging activity among the test oils, and the total phenol content was found positively correlated to the antioxidant capacity of L. edodes oil, which could be well predicted by all MLR models. These findings revealed the influence of solvent on the chemical characterization and in vitro antioxidant capacity of L. edodes oil, providing a theoretical foundation for future applications of L. edodes oil.
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... The effectiveness of the natural antimicrobials CIN and VN, as well as their respective encapsulated systems E-CIN and E-VN, and their combinations (E-CIN + E-VN) was evaluated on three microorganisms, Escherichia coli, Listeria innocua, and Saccharomyces cerevisiae, following the methodology of Sepúlveda et al. (2024) [29]. The free antimicrobial or the appropriate volume of the respective encapsulated system was added to the beverage under constant stirring, reaching 0.75 g/L or 1.0 g/L for cinnamaldehyde, and 1.0 g/L or 1.5 g/L for vanillin. ...
... The free antimicrobial or the appropriate volume of the respective encapsulated system was added to the beverage under constant stirring, reaching 0.75 g/L or 1.0 g/L for cinnamaldehyde, and 1.0 g/L or 1.5 g/L for vanillin. It is worth mentioning that L. innocua was only evaluated with 0.75 g/L of CIN and E-CIN, 1.5 g/L of VN and E-VN, and the combined treatments because the rest of the treatments were reported in a previous study [29]. Each microorganism (100 µL) was inoculated to reach a final inoculum density of approximately 5 × 10 5 CFU/mL. ...
... One possible explanation is that, due to differences in the cell walls, Gram-negative bacteria present a lipopolysaccharide outer membrane that protects them from damage caused by various inhibitors [30]. The great sensitivity of S. cerevisiae against CIN was already observed in laboratory media by Liu et al. (2021) [1]. These authors used CIN 0.25 g/L, obtaining a reduction of 6 log cycles after 40 h of storage at 35 • C [1]. ...
Many studies have suggested that the encapsulation of natural antimicrobials increases their antimicrobial activity. In this sense, the objective was to study the inactivation of microorganisms with encapsulated cinnamaldehyde and vanillin (E-CIN and E-VN), in comparison with the unencapsulated antimicrobials (CIN and VN) in protein beverages. Additionally, the microbial response was quantified through mathematical modeling. Cinnamaldehyde and vanillin were encapsulated using whey protein concentrate (WPC) as the encapsulating agent. The effectiveness at inactivating Escherichia coli, Listeria innocua, and Saccharomyces cerevisiae was evaluated in a protein-apple juice beverage during storage (4 °C). Encapsulation increased the effectiveness of cinnamaldehyde, reaching reductions of 1.8, 3.3, and 5.3 log CFU/mL in E. coli, L. innocua, and S. cerevisiae, respectively, while vanillin encapsulation had little effect on antimicrobial activity, reducing by 0.5, 1.4, and 1.1 log cycles, respectively. The combined treatments (E-CIN + E-VN) had an additive effect in reducing E. coli and a synergistic effect against S. cerevisiae. The Gompertz model was more versatile and better described the biphasic curves, whereas the Weibull model complemented the information regarding the spectrum of resistances within the microbial population. In conclusion, the encapsulation of cinnamaldehyde with WPC enhanced its activity. However, further studies are necessary to improve the antimicrobial activity of vanillin.
... The various chemical compositions of essential oils enable them to target multiple sites within bacterial cells, and their hydrophobic properties facilitate penetration of the cytoplasmic membrane [10]. It was reported that the emulsified cedarwood essential oil directly interacted with bacterial cell membranes, facilitating the interaction and improving the antibacterial activity [12]. Other bioactive extracts, such as curcumin and resveratrol, also exhibit significant antibacterial effects against foodborne bacteria and have positive effects on human health. ...
... chitosan, pectin, cellulose) are commonly used as Pickering emulsion stabilizers for food applications and have good encapsulation efficiency for antibacterial agents that target foodborne bacteria. The properties of stabilizers and the preparation methods of Pickering emulsions determine the particle size and surface charge of emulsion droplets, which significantly influence the effectiveness against foodborne bacteria [2,12]. For instance, smaller particles possess a larger surface area that may enable stronger interactions with bacteria and enhance antibacterial efficacy, while larger particles usually have prolonged release of antibacterial agents. ...
... The TSI value intuitively expressed the sedimentation characteristics of the suspension. The lower the TSI value, the better the dispersion stability of the suspension [21]. Figure 3(b) shows the TSI curves of the casting slurry at 48 h. ...
The casting slurry determines the quality of the low-temperature co-fired ceramic (LTCC) green tapes. In the present investigation, large amplitude oscillatory shear (LAOS) is first exploited to characterize the rheological properties of casting slurry. Three kinds of casting slurries with different plasticizer contents were cast into green tapes and studied. Furthermore, comprehensive performance tests were carried out on the obtained green tapes, which showed matching nonlinear rheological properties with those of casting slurries, as obtained by LAOS tests. It revealed that the addition of an appropriate amount of plasticizer (plastic/binder = 0.5) can significantly improve the structural uniformity of the slurry. The green tapes at this content also had high tensile strength and excellent yield elongation. This study combines the internal microstructure of the casting slurry and the external comprehensive performance of green tapes according to LAOS tests. The optimal plasticizer content can be quickly and accurately obtained from the rheological theory.
... Cedarwood essential oil is widely used in fragrances, as well as in scented soaps, aerosols and sprays, disinfectants, for cleaning microscope parts and immersion lenses (Paniwnyk, 2017). The essential oil of cedar has antifungal, antimicrobial (Hawkins et al., 2022;Prosekov et al., 2018;Ramadass et al., 2019;Tamer et al., 2022), antiviral, molluscicidal properties (Huang et al., 2021;Perdones et al., 2016), and also exhibits antiinflammatory activity (Pandey et al., 2016;Poaty et al., 2015;Taghavi et al., 2023). Have been shown that Escherichia coli, Bacillus subtilis and Bacillus cereus are susceptible to cedarwood essential oil (Pandey et al., 2016;Kačániová et al., 2022). ...
The properties of fir and cedar essential oils are very diverse. The main ones are antibacterial, anti-inflammatory, antifungal and antiviral. Furthermore, fir and cedar essential oils help to speed up metabolism and reduce stress. Currently, a lot of research is being done on the anti-cancer properties of these oils. The developed nanoemulsion makes it possible to use all the valuable substances of fir and cedar essential oils. Products with it can be used to prevent neoplasms in the human body and improve the functioning of the muscular system and individual organs, such as the liver. The interest in ultrasonic processing is based on the beneficial properties it brings to food products, particularly, disinfection, emulsification, intensification of some technological processes, and so on. Various creams, suspensions and emulsions are produced using ultrasonic processing. All over the world, research is underway to obtain and study the properties of these solutions. In this study, a technology for obtaining a stable nanoemulsion (oil-water) using ultrasonic vibrations has been developed. The results showed that the nanoemulsion with using Tween 80 emulsifier is the most stable. The rational ratio of oil: emulsifier: water was determined. The optimal surfactant for obtaining a stable emulsion is the TWEEN 80 emulsifier at a concentration twice the concentration of oils - the ratio of emulsifier to oil is 1:2, respectively. The appearance and formula of the emulsion obtained by ultrasonic generator is much better than that obtained by dispersion and mixing. To obtain a stable emulsion, treatment with an ultrasonic generator at a frequency of 22 kHz, power of 100% and processing in an ice bath is necessary. A comparative analysis of the appearance and stability of the obtained nanoemulsion was carried out in comparison with nanoemulsions obtained by other methods. This nanoemulsion can be used in the food industry to improve the antibacterial activity in food products, prolong the shelf life, and increase the nutritional value. Moreover, developed nanoemulsion can be widely used in the cosmetic and pharmaceutical industries for both oral preparations and transdermal use.
... Moreover, the strength of BS increased and the curve smoothed when HIPPEs were at high glycerol ratios (25 %-30 %), which might be the increase in emulsification degree. However, the BS intensity also decreased to a certain extent with the in-crease in scanning time relating to coalescence and flocculation [51]. When the size of colloidal particles is >0.6 μm, colloidal coalescence will lead to a decrease in BS [52]. ...
Exploring the emulsification of myofibrillar protein (MP) from large yellow croaker (Larimichthys crocea) could meet the demand for high-value development and utilization of fish proteins. Therefore, MPs as the emulsifier to form stable high internal-phase Pickering emulsions (HIPPEs) with the addition of glycerol and the effects of different glycerol addition ratios of HIPPEs were investigated. HIPPEs could be constructed by MPs with the glycerol addition at a ratio of 15 %–30 % (v/v) compared to those without the addition of glycerol. With the increase in glycerol ratios, the absolute value of Zeta potential increased and reached 22.57 ± 0.29 mV at the glycerol ratio of 30 %. All the HIPPEs stabilized by MPs with the addition of glycerol possessed storage stability. Besides, the centrifugal stability constant (Ke), backscattered light intensity and reflected light stability index confirmed that the addition of glycerol was beneficial for the formation of stable HIPPEs prepared by MPs. Additionally, HIPPEs stabilized by MPs with the addition of glycerol possessed small emulsion droplets and viscoelastic behavior. These findings could be helpful for the development and utilization of MPs of large yellow croaker in the food industry.
... This improvement is likely attributed to surfactants in the microemulsion, which facilitate the cellular permeability of eugenol, thereby amplifying its antimicrobial efficacy (Bai et al., 2023). Notably, the emulsification of CO has been previously recognized as a technological approach to enhance natural compounds' antimicrobial activity [63]. ...
A novel sanitizer tablet containing clove essential oil (CO) microemulsion was developed. A preformulation study using nuclear magnetic resonance and thermal analyses showed component compatibility. The main components of the samples remained intact despite a color change, probably due to a strong acid-base interaction between eugenol and diethanolamine. The CO microemulsion showed acaricidal and larvicidal activities superior to the commercial product, with product efficacy of 99.9% and larvae mortality of 94%. Optimal spray-drying conditions were achieved with inlet and outlet temperatures of 50°C and 40°C, respectively, an aspiration rate of 1 m³ min⁻¹, and a 0.25 L h⁻¹ injection flow. The feed suspension comprised 50% (v/v) liquid soap, 37.5% (v/v) water, 12.5% (v/v) ethanol, and 5.0% (w/v) silica. This formulation and processing parameters allowed for successful free-flow powder formation, providing a suitable matrix for incorporating the CO microemulsion via wet granulation without heating. Finally, sanitizer tablets produced from such granules resulted in a uniform product with low weight variation (coefficient of variation of 0.15%), eugenol content of 95.5% ± 3.3, and friability of 0.58%. Furthermore, the tablets showed rapid aqueous dispersion, forming a colloidal system with particle sizes of 221 nm and a zeta potential of -17.2 mV. Antimicrobial activity tests demonstrated the effectiveness of the sanitizer tablet against bacteria and fungi, exhibiting comparable antimicrobial potency to isolated CO. Hence, the sanitizer tablet developed represents a promising candidate as a practical and efficient solution for pest control, offering strong antimicrobial and acaricidal activity.
... The presence of salt ions might dilute the Pickering emulsion, thereby reducing the modulus. 24 With the decreased of NaCl addition, the viscosity showed an upward trend (Fig. 3H). The increase in viscosity prevented the merger of dispersed phases, increased the coalescence time, reduced the coalescence stability and made the emulsion more stable, indicating that the addition of NaCl was unfavorable to the stability of the emulsion. ...
BACKGROUND
Cellulose nanofiber (CNF) is an ideal Pickering emulsion stabilizer because of its high aspect ratio and flexibility. CNF was hydrophobically modified by dodecenyl succinic anhydride and used to stabilize the simulated food emulsion system containing insect protein. The prepared dodecenyl succinate nanofiber (D‐CNFs) was characterized by contact angle and laser particle size analyzer. The stability of the emulsion system under different conditions was characterized by zeta potential and appearance observation. Lastly, in vitro digestion simulation experiments were carried out to investigate whether the addition of D‐CNFs had an effect on the digestion and absorption of oil.
RESULTS
The modification process for dodecenyl succinic anhydride to CNFs was that the system temperature was 40 °C, the system pH value was 8.5 and the reaction time was 6 h. The water contact angle of the modified CNFs increased to 83.2 ± 0.9°. D‐CNFs were introduced into the simulated food emulsion system containing insect protein. The increase in the concentration of D‐CNFs in the aqueous phase promoted the stability of the simulated emulsion system. Increasing the ratio of insect protein was not conducive to the stability of the emulsion. The final fat digestibility of the emulsion with D‐CNFs was lower than that of the emulsion without D‐CNFs.
CONCLUSION
Overall, the analysis and characterization results show the potential of the modified CNF as a food simulant emulsion stabilizer containing insect protein, which can be used for the development of specific functional foods. © 2024 Society of Chemical Industry.
... With the Trolox methanol solution (10-180 µmol/L) as an antioxidant standard, the antioxidant activity of DF in vitro was measured by three indicators, i.e., 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) and 2,2 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging activity as well as the ferric ion reducing antioxidant power (FRAP). The exact processes were conducted according to some previous reports [42][43][44], with some modifications. A mixture containing 2 g of DF sample and 6 mL of methanol was stirred by a vortex oscillator for 3 min. ...
Agrocybe cylindracea dietary fiber (ADF) contains 95% water-insoluble dietary fiber, resulting in poor application performance. To address this issue, ADF was modified by four methods (cellulase, sodium hydroxide, high-temperature, and Lactobacillus fermentation) in this paper. By comparing the physicochemical properties, microstructures, monosaccharide compositions, and functional characteristics (antioxidant and α-glucosidase inhibitory activities in vitro) of all modified ADF samples, the optimal modification method was selected. Results showed that sodium hydroxide treatment was deemed the most effective modification method for ADF, as alkali-treated ADF (ADF-A) revealed a higher oil-holding capacity (2.02 g/g), swelling capacity (8.38 mL/g), cholesterol adsorption (6.79 mg/g), and α-glucosidase inhibitory activity (more than 70% at 0.4–0.6 mg/mL) than the other modified samples. The looser microstructure in ADF-A might be attributed to molecular rearrangement and spatial structure disruption, which resulted in smaller molecular sizes and decreased viscosity, hence improving ADF’s physicochemical and functional qualities. All these findings indicate the greater application potential of modified ADF products in food and weight-loss industries, providing a comprehensive reference for the industrial application of ADF.
... The impact of LCLE on cells' microbial appearance was investigated according to SEM observation. 22 LCLE at levels of 1 × MIC and 2 × MIC and sterile normal saline were used to treat the S. epidermidis suspensions (10 5 CFU/mL) for 24 h, respectively. Sterile regular saline was considered as the blank control. ...
Liriodendron chinense has been widely utilized in traditional Chinese medicine to treat dispelling wind and dampness and used for alleviating cough and diminishing inflammation. However, the antioxidant, antimicrobial, and anti-inflammatory effects of L. chinense leaves and the key active constituents remained elusive. So, we conducted some experiments to support the application of L. chinense in traditional Chinese medicine by investigating the antioxidant, antibacterial, and anti-inflammatory abilities, and to identify the potential key constituents responsible for the activities. The ethanol extract of L. chinense leaves (LCLE) was isolated and extracted, and assays measuring ferric reducing antioxidant power, total reducing power, DPPH•, ABTS•+, and •OH were used to assess its in vitro antioxidant capacities. Antimicrobial activities of LCLE were investigated by minimal inhibitory levels, minimum antibacterial concentrations, disc diffusion test, and scanning electron microscope examination. Further, in vivo experiments including macro indicators examination, histopathological examination, and biochemical parameters measurement were conducted to investigate the effects of LCLE on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. LCLE was further isolated and purified through column chromatography, and LPS-induced RAW264.7 cells were constructed to assess the diminished inflammation potential of the identified chemical composites. ABTS•+ and •OH radicals were extensively neutralized by the LCLE treatment. LCLE administration also presented broad-spectrum antimicrobial properties, especially against Staphylococcus epidermidis by disrupting cell walls. LPS-induced ALI in mice was significantly ameliorated by LCLE intervention, as evidenced by the histological changes in the lung and liver tissues as well as the reductions of nitric oxide (NO), TNF-α, and IL-6 production. Furthermore, three novel compounds including fragransin B2, liriodendritol, and rhamnocitrin were isolated, purified, and identified from LCLE. These three compounds exhibited differential regulation on NO accumulation and IL-10, IL-1β, IL-6, TNF-α, COX-2, and iNOS mRNA expression in RAW264.7 cells induced by LPS. Fragransin B2 was more effective in inhibiting TNF-α mRNA expression, while rhamnocitrin was more powerful in inhibiting IL-6 mRNA expression. LCLE had significant antioxidant, antimicrobial, and anti-inflammatory effects. Fragransin B2, liriodendritol, and rhamnocitrin were probably key active constituents of LCLE, which might act synergistically to treat inflammatory-related disorders. This study provided a valuable view of the healing potential of L. chinense leaves in curing inflammatory diseases.
... The DPPH scavenging capacity of emulsions was measured according to the method reported in [43], with slight modifications. Briefly, 1 mL of emulsion was added to 2 mL of DPPH solution and immediately stirred. ...
A reliable strategy for improving the stability and shelf life of protein-stabilized systems is by covalently attaching the protein onto a polysaccharide. In this study, ovalbumin (OVA) was modified with dextran (DEX) of different molecular weights by the Maillard reaction, and was used to enhance the stability of emulsions loaded with resveratrol. The surface hydrophobicity, thermal stability, and FT-IR spectroscopy of the OVA–DEX conjugates were evaluated. The results showed that the surface hydrophobicity of OVA decreased, while the thermal stability of OVA was significantly improved after DEX covalent modification. The OVA–DEX1k-stabilized emulsion exhibited high encapsulation efficiency of resveratrol, with the value of 89.0%. In addition, OVA–DEX was considerably more effective in droplet stabilization against different environmental stresses (heat, pH, and ionic strength). After 28 days of storage at 25 °C, the OVA-stabilized emulsion showed faster decomposition of resveratrol, whereas the OVA–DEX-conjugate-stabilized emulsion had approximately 73% retention of resveratrol. Moreover, the antioxidant activity of resveratrol-loaded emulsions stabilized by OVA–DEX was higher during storage under different temperatures. These results proved that the OVA–DEX conjugates had the potential to form stable, food-grade emulsion-based delivery systems against environmental stresses, which strongly supports their potential in the field of food and biomedical applications.
... This measurement was conducted at the day of emulsion formulation. The DPPH radical scavenging ability of the emulsions was determined using the method described by Huang et al., with slight modifications [22]. Briefly, 0.5 mL of the emulsion samples was added to 0.5 mL of ethanolic DPPH solution (0.1 mM). ...
In response to environmental issues, upcycling has become a growing trend in the food industry. Aquasoya is a promising method to upcycle by-product from soybean processing due to its high protein contents and excellent emulsifying ability. In the present research, Aquasoya powder was used an emulsifier to incorporate the antioxidant compounds from perilla skin extract (PSE), namely rosmarinic acid, into oil-in-water (O/W) emulsion system and its physochemical stability was assessed. As a result, droplet size of the emulsion was smaller in PSE-incorporated emulsion (PO, 350.57 ± 9.60 b nm) than the emulsion without PSE (PX, 1045.37 ± 142.63 a nm). Centrifugal photosedimentometry analysis also revealed that the physical stability was significantly improved in PO, and the stability was maintained over 30 d of storage. Furthermore, as PO had a higher ABTS radical scavenging ability and showed slower initial lipid oxidation, it was concluded that PO has a higher antioxidant ability than PX. Conclusively, Aquasoya can be considered as an emulsifier in O/W emulsion with PSE because it can effectively integrate and stabilize the antioxidant substance derived from perilla skin.
... where C 1 represents the concentration of vitamin E of the supernatant (g/mL), C 2 represents the concentration of vitamin E of the emulsion (g/mL), C 3 represents the concentration of vitamin B 12 of the supernatant (g/mL), and C 4 represents the concentration of vitamin B 12 of the emulsion (g/mL). The approach of Huang et al. [18] was slightly modified to evaluate the DPPH radical scavenging activity of the emulsion. Next, 3 mL DPPH solution (0.25 mmol/L) was mixed with 0.3 mL of the sample, which was prepared with anhydrous ethanol. ...
In this study, the soybean protein isolate (SPI)–xanthan gum (XG) or carrageenan (CA) W/O/W emulsions for the co-delivery of vitamin B12 and vitamin E were prepared. The effects of XG and CA concentrations on the physicochemical properties and digestive characteristics of the emulsions were also investigated. The addition of XG and CA improved the SPI aggregation and increased its electrostatic repulsion so that more SPI was adsorbed at the phase interface. The emulsifying activity index and emulsifying stability index increased to 24.09 (XG 0.4%) and 14.00 (CA 0.5%) and 151.08 (XG 0.4%) and 135.34 (CA 0.5%), respectively. The adsorbed protein content increased to 88.90% (XG 0.4%) and 88.23% (CA 0.5%), respectively. Moreover, the encapsulation efficiencies of vitamin B12 and vitamin E were increased to 86.72% (XG 0.4%) and 86.47 (CA 0.5%) and 86.31% (XG 0.4%) and 85.78% (CA 0.5%), respectively. The bioaccessibility of vitamin B12 and vitamin E increased to 73.53% (XG 0.4%) and 71.32% (CA 0.5%) and 68.86% (XG 0.4%) and 68.74% (CA 0.5%). The best properties of the emulsions were obtained at a 0.4% concentration of XG and 0.5% of CA. This study offers a novel system for delivering bioactive substances, which is favorable for the advancement of food with delivery capability in food processing.
... These measurements were effectuated on native samples without any dilution. The instrument software (Turbiscan Easy Soft) calculates the TSI value (see Equation (4)) that is used to predict dispersion stability [65]; the smaller TSI value corresponds to a more stable system. In this study, TSI variation over 24 h of analysis was monitored, comparing the CNCs@Th-EO NE_1 immediately after preparation and after 30 days. ...
Essential oil-based pesticides, which contain antimicrobial and antioxidant molecules, have potential for use in sustainable agriculture. However, these compounds have limitations such as volatility, poor water solubility, and phytotoxicity. Nanoencapsulation, through processes like micro- and nanoemulsions, can enhance the stability and bioactivity of essential oils. In this study, thyme essential oil from supercritical carbon dioxide extraction was selected as a sustainable antimicrobial tool and nanoencapsulated in an oil-in-water emulsion system. The investigated protocol provided high-speed homogenisation in the presence of cellulose nanocrystals as stabilisers and calcium chloride as an ionic crosslinking agent. Thyme essential oil was characterised via GC-MS and UV-vis analysis, indicating rich content in phenols. The cellulose nanocrystal/essential oil ratio and calcium chloride concentration were varied to tune the nanoemulsions’ physical–chemical stability, which was investigated via UV-vis, direct observation, dynamic light scattering, and Turbiscan analysis. Transmission electron microscopy confirmed the nanosized droplet formation. The nanoemulsion resulting from the addition of crosslinked nanocrystals was very stable over time at room temperature. It was evaluated for the first time on Pseudomonas savastanoi pv. savastanoi, the causal agent of olive knot disease. In vitro tests showed a synergistic effect of the formulation components, and in vivo tests on olive seedlings demonstrated reduced bacterial colonies without any phytotoxic effect. These findings suggest that crosslinked cellulose nanocrystal emulsions can enhance the stability and bioactivity of thyme essential oil, providing a new tool for crop protection.
... Moreover, our finding is in good agreement with other studies showing enhanced antioxidant activity of EOs and active compounds after formulation (Lou et al. 2017). A study comparing the antioxidant activity of Cedarwood EO in its free and nano-emulsified states has demonstrated that the NE system resulted in higher DPPH and ABTS radical-scavenging activities and iron reducing ability in a dose-dependent manner (Huang et al. 2021). Several studies have utilized NE in delivering anti-antioxidant compounds (Khatamian et al. 2022). ...
Formulating a nanoemulsion (NE) of essential oil (EO) could enhance its efficiency while requiring lower concentrations. Eucalyptus cladocalyx F. Muell EO was rich in monoterpenes hydrocarbons. NE was prepared and the effect of surfactant (Tween 20, 40 and 80) and shearing time were investigated. The results showed that the best NE was formed using Tween 80 after 25 min of emulsification. Small droplet size (40 nm), low polydispersity index PDI (0.49), and stable zeta potential highlighted the excellent NE stability which was tested under storage conditions for 4 months. The results showed that the antioxidant and anticancer activities of NE were enhanced compared to free EO. Furthermore, NE and EO exhibited high anti-inflammatory effects by inhibiting nitric oxide (NO), Interleukin 6 (IL-6), and tumor necrosis factors alpha (TNF-α) production in liposaccharides (LPS)-induced RAW264.7 cells. In conclusion, a stable Eucalyptus cladocalyx-NE was produced, with improved biological activities.
... However, it is noteworthy that this variation was more pronounced at 65 • C as opposed to 25 • C, thereby implying that lower temperatures are more conducive to maintaining the stability of the emulsion. The reason for this phenomenon may be that high viscosity at low temperatures limited the migration and movement of particle size, and high temperatures might increase the possibility of collisions of oil molecules, thus accelerating the destruction process [35]. Compared with Fig. 4B, the shape of ΔBS curve at the top of the emulsion in Fig. 4D changed, and the strength of ΔBS decreased, indicating that application of ultrasonic waves could enhance the emulsions stability at 65 • C. Careful comparison showed that the influence of ultrasonic treatment on the top ΔBS curve of the emulsion stored at 65 • C was less than that at 25 • C. ...
Multi-frequency power ultrasound was applied as an environmentally friendly technique to control the nanoparticles (LS/XG-NPs) embedded with lotus root starch/xanthan gum, with the aim of enhancing the stability of Pickering emulsions. The present investigation was centered on evaluating the impact of ultrasound technology on various aspects of the emulsions, encompassing their mean particle size, particle size distribution, zeta potential, microstructure, rheological characteristics, and environmental stability. The findings of this study indicate that ultrasonic treatment enhanced the adsorption of LS/XG-NP onto oil droplets surface, resulting in a reduction in their size. Additionally, ultrasonic treatment decreased the viscosity and Brownian motion rate of the emulsion stabilized by LS/XG-NP, leading to increased fluidity. Furthermore, the emulsion's thermal stability and resistance to environmental oxidation were significantly enhanced through ultrasonic treatment. The Pickering emulsions that were prepared using ultrasound demonstrated excellent resistance to acid, alkali (pH 2–8) and salt ions (50–300 mM NaCl) for a period of 30 days during storage. It was worth anticipating that ultrasound-assisted LS/XG-NPs could efficiently retard the volatilization of fishy odor components within fish oil. Taken together, the present research has evinced the efficacy of ultrasound in enhancing the stability of Pickering emulsions coated with LS/XG-NPs. These findings offer significant novel insights into the advancement of ultrasound-assisted Pickering emulsions that are stabilized with starch-based or biopolymeric materials.
... Nevertheless, such values also confirm the stability of the samples over time because, according toŚliwkowska [62], formulations with a TSI >10 are considered unstable. In addition, the TSI results obtained for the considered systems in this work are within the range of those obtained by Huang et al., 2021 concerning two cedarwood essential oil emulsions [63]. Similarly, the TSI value (approximately 2.3 to 5.3) in this study that confirmed product stability was also presented in the work by Nizioł-Łukaszewska et al., 2018 for body lotions [64]. ...
Psoriasis is a chronic disorder that causes a rash with itchy, scaly patches. It affects nearly 2–5% of the worldwide population and has a negative effect on patient quality of life. A variety of therapeutic approaches, e.g., glucocorticoid topical therapy, have shown limited efficacy with systemic adverse reactions. Therefore, novel therapeutic agents and physicochemical formulations are in constant need and should be obtained and tested in terms of effectiveness and minimization of side effects. For that reason, the aim of our study was to design and obtain various hybrid systems, nanoemulgel–macroemulsion and nanoemulgel–oleogel (bigel), as vehicles for ursolic acid (UA) and to verify their potential as topical formulations used in psoriasis treatment. Obtained topical formulations were characterized by conducting morphological, rheological, texture, and stability analysis. To determine the safety and effectiveness of the prepared ursolic acid carriers, in vitro studies on human keratinocyte cell-like HaCaT cells were performed with cytotoxicity analysis for individual components and each formulation. Moreover, a kinetic study of ursolic acid release from the obtained systems was conducted. All of the studied UA-loaded systems were well tolerated by keratinocyte cells and had suitable pH values and stability over time. The obtained formulations exhibit an apparent viscosity, ensuring the appropriate time of contact with the skin, ease of spreading, soft consistency, and adherence to the skin, which was confirmed by texture tests. The release of ursolic acid from each of the formulations is followed by a slow, controlled release according to the Korsmeyer–Peppas and Higuchi models. The elaborated systems could be considered suitable vehicles to deliver triterpene to psoriatic skin.
... After saponifying the mushroom oil by alkaline hydrolysis, the mixture containing alcoholic potassium hydroxide was extracted by nhexane to obtain unsaponifiable matter. To ensure full saponification and precise quantification, the oil sample (0.2 g) was mixed with 3 mL The ABTS radical cation decolorization assay of mushroom oil was performed based on a study by Huang et al. (2021) with a slight change. A working solution containing ABTS (3.5 mmol/L) and potassium persulfate (1.3 mmol/L) was stored at room temperature for 12-16 h before use. ...
The biological activity of an oil not only depends on its fatty acid composition but also the lipid composition and trace components. In this paper, to select the optimal mushroom oil, the component compositions (fatty acids, lipids, polyphenols, flavones, tocopherols, and unsaponifiable matters) and antioxidant activities in vitro of four mushroom oils ( Agrocybe cylindracea , two Lentinula edodes , and Volvariella volvacea) were investigated and compared. The results showed that the four tested oils had the same fatty acid composition in different amounts, but the lipid component, minor components, and free radical scavenging activity in the tested oils varied widely depending on the type of mushroom. Overall, Volvariella volvacea oil was considered superior to the other three tested oils, as it had the largest contents of polar lipids, diglycerides, polyunsaturated fatty acids (74.38%), unsaponifiable matter (319.09 mg/kg), total phenols (124.08 mg/100 g), tocopherols (139.86 mg/100 g), as well as the highest ABTS and FRAP values (349.45 and 3801.70 μmol Trolox/100 g). This finding suggests that Volvariella volvacea oil is a promising resource that should be further researched.
Background/Objectives: Essential oils (EOs) represent a natural alternative to chemical additives due to their biological activity. This study evaluated the antimicrobial and antioxidant activities of basil and winter savory EO mixtures, their interactions, and the biological potential of chitosan-based nano-encapsulated EO mixtures. Methods: Mixtures of basil and winter savory EOs (ratios 1:1, 2:1, 4:1, 8:1, and 16:1) were analyzed for chemical composition via GC–MS. Antimicrobial activity was assessed using minimal inhibition (MIC) and bactericidal (MBC) concentration assays, and interactions were quantified with fractional inhibitory concentration indices (FICIs). Antioxidant activity was evaluated using the DPPH assay, with combination indices used to interpret interaction effects. Chitosan-based nanoparticles were made with the selected oil mixture (2:1), after which characterization and biological activity were performed. Results: The EO mixture with 2:1 ratio exhibited the strongest joint activity, with synergistic or additive effect against four out of six analyzed microorganisms. Antioxidant activity improved with higher basil proportions, with the 16:1 ratio achieving the lowest EC50 value of 0.052 mg/mL after 120 min and demonstrating synergistic effects at all tested ratios. Higher basil EO content also masked the strong odor of winter savory EO. The biological activity of chitosan-based nanoparticles was increased by encapsulation of the EO mixture (2:1), with an encapsulation efficiency of 75.39%. Conclusions: The EO mixture (2:1) showed best antimicrobial efficacy, with synergistic or additive effects. The nano-encapsulated mixture showed good biological potential with effective and complete odor neutralization. These results indicate the potential of basil and winter savory essential oil mixtures for sustainable food preservation applications.
With a widespread distribution throughout the Northern Hemisphere and 11 genera, Pinaceae is the largest family of Gymnosperms in the world. Essential oils are an important chemotaxonomic marker for the species of this family, although the degree of chemical and biological investigation has not been the same for all genera. Essential oils from Abies and Cedrus (from the abietoid clade) or Pinus and Picea (from the pinoid clade) have been more extensively investigated with respect to their chemical composition and biological or pharmacological properties, including their antioxidant effects. Instead, essential oils from the other genera of the family have been less explored in this respect or even have not been investigated at all. This is a narrative review looking into the knowledge acquired up to date, the variability and limitations of the current methods used to estimate antioxidant effects, and multiple comparisons between EOs obtained from different genera, species, and plant parts, as well as potential applications and future directions of research and utilization of essential oils derived from Pinaceae species.
Surface-active compounds (SACs) of microbial origin are an active group of biomolecules with potential use in the formulation of emulsions. In this sense, the present study aimed to isolate and select yeasts from fruits that could produce SACs for essential oil emulsions. The Candida krusei M4CK was isolated from the Byrsonima crassifolia fruit to make SACs. This emulsification activity (E24) was equal to or greater 50% in all carbon sources, such as olive oil, sunflower oil, kerosene, hexane, and hexadecane. E24 followed exponential growth according to the growth phase. The stability of emulsions was maintained over a wide range of temperatures, pH, and salinity. The OMBE4CK (melaleuca essential oil emulsion) had better and more significant inhibitory potential for biofilm reduction formation. In addition, bioemulsifier BE4CK alone on Escherichia coli and Pseudomonas aeruginosa biofilm showed few effective results, while there was a significant eradication for Staphylococcus aureus biofilms. The biofilms formed by S. aureus were eradicated in all concentrations of OMBE4CK. At the same time, the preformed biofilm by E. coli and P. aeruginosa were removed entirely at concentrations of 25 mg/mL, 12.5 mg/mL, and 6.25 mg/mL. The results show that the bioemulsifier BE4CK may represent a new potential for antibiofilm application.
Beneficial microorganisms and plant essential oils are key components of sustainable agriculture, but knowledge of their compatibility is limited. We investigated the effect of 23 essential oils on three beneficial bacterial species (Bacillus cereus, Bacillus velezensis and Priestia megaterium) that are commercially used as biostimulants and biocontrol antagonists. Essential oils were tested at a dilution of 1:10, the highest economical use rate anticipated in crop protection applications. Seventeen of the 23 essential oils had no inhibitory activity against any of the three bacterial species. Onion essential oil had strong activity against B. velezensis and no activity against B. cereus or P. megaterium. Palmarosa and pimenta essential oils were active against B. velezensis and inactive against B. cereus and P. megaterium. Coriander essential oil was inactive against B. velezensis, active against B. cereus, and strongly active against P. megaterium. Oregano essential oil was active against the three bacterial species while garlic essential oil was active against B. cereus and strongly active against B. velezensis and P. megaterium. Allyl disulfide, carvacrol, eugenol, and geraniol, the major constituents of garlic, oregano, pimenta leaf, and palmarosa/coriander essential oils, respectively, were active or strongly active against at least two of the three bacterial species suggesting their contribution to the antimicrobial activity of these essential oils. These findings indicate that most of the essential oils tested are compatible with beneficial microbes and can easily be integrated with beneficial microbes in organic cropping systems. Further studies should investigate how to harness the pesticidal properties of the six active essential oils while limiting their detrimental effect on beneficial microbes.
Extracellular vesicles (EVs), including exosomes and microvesicles (<200 nm), play a vital role in intercellular communication and carry a net negative surface charge under physiological conditions. Zeta potential (ZP) is a popular method to measure the surface potential of EVs, while used as an indicator of surface charge, and colloidal stability influenced by surface chemistry, bioconjugation, and the theoretical model applied. Here, we investigated the effects of such factors on ZP of well-characterized EVs derived from the human choriocarcinoma JAr cells. The EVs were suspended in phosphate-buffered saline (PBS) of various phosphate ionic concentrations (0.01, 0.1, and 1 mM), with or without detergent (Tween-20), or in the presence (10 mM) of different salts (NaCl, KCl, CaCl2, and AlCl3) and at different pH values (4, 7, and 10) while the ZP was measured. The ZP changed inversely with the buffer concentration, while Tween-20 caused a significant (p < 0.05) lowering of the ZP. Moreover, the ZP was significantly (p < 0.05) less negative in the presence of ions with higher valency (Al³⁺/Ca²⁺) than in the presence of monovalent ones (Na⁺/K⁺). Besides, the ZP of EVs became less negative at acidic pH, and vice versa. The integrated data underpins the crucial role of physicochemical attributes that influence the colloidal stability of EVs.
In this paper, the effects of four different temperatures (5, 25, 37 and 50°C) on the physical stability and the dynamic and steady-state shear rheological properties of sunflower oil-in-water emulsions prepared with gum tragacanth were investigated. Emulsions showed excellent stability against various instability mechanisms after 150 days storage at 5 and 25°C. The experimental data had the best fit with power law model (R 2 > 0.99). The effect of temperature on power law parameters was determined. The increase of temperature from 5 to 50°C resulted in 4 times decrease in the flow consistency index, whereas the flow behavior index slightly enhanced with temperature (0.49–0.58). For all samples loss modulus (G″) was higher than the storage modulus (G′) in the low frequency range and G′ increased faster than G″ with frequency enhancement. A modified Cox–Merz rule was valid to emulsion samples using shift factors.
Fenugreek (Trigonella-Foenum Graecum) is known as one of the traditional and most promising medicinal herbs belongs to the leguminous family. The seeds of fenugreek have been extensively studied for the treatment of inflammation, cancer and diabetes. In this study, fenugreek seed oil was extracted and evaluated for its chemical compositions and bonding through gas chromatography coupled to mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR) analysis, respectively. The antioxidant activity against 2,2- diphenyl- picrylhydrazyl (DPPH) and 2,2ʹ-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS+•) radicals, total phenolic content (TPC) and total flavonoid content (TFC) of the oil were also studied. The capacity of antioxidants detected by ABTS was stronger than that by DPPH. A total number of 23 chemical compounds were detected and identified in fenugreek seed oil comprising of 99% of the total oil through GC-MS analysis. The major compounds of the extracted oil were linoleic acid (54.13 %), palmitic acid (16.21 %), pinene (4.56%), 4-Pentyl-1- (4-propylcyclohexyl)-1-cyclohexene (3.87%) and linoleic acid methyl ester (3.19%). FTIR
2
analysis confirmed the presence of carboxyl group in the oil which were more dominated by unsaturated essential fatty acids. Moreover, the oil of fenugreek seed indicated a strong antioxidant radical scavenging activity against both DPPH and ABTS assays with an IC50 of 172.6 ± 3.1 and 161.3 ± 2.21, respectively. The TPC and TFC of the oil were 38.97 ± 0.34 mg GAE/g. oil and 14.417 ± 0.23 mg QE/g.oil. Thus, this study suggests that the fenugreek seed oil could be used for pharmaceutical purposes.
Keywords:
Citral is a typical essential oil used in the food, cosmetic, and drug industries and has shown antimicrobial activity against microorganisms. Citral is unstable and hydrophobic under normal storage conditions, so it can easily lose its bactericide activity. Nanoemulsion technology is an excellent way to hydrophilize, microencapsulate, and protect this compound. In our studies, we used a mixed surfactant to form citral-in-water nanoemulsions, and attempted to optimize the formula for preparing nanoemulsions. Citral-in-water nanoemulsions formed at So 0.4 to 0.6 and ultrasonic power of 18 W for 120 seconds resulted in a droplet size of < 100 nm for nanoemulsions. The observed antimicrobial activities were significantly affected by the formulation of the nanoemulsions. The observed relationship between the formulation and activity can lead to the rational design of nanoemulsion-based delivery systems for essential oils, based on the desired function of antimicrobials in the food, cosmetics, and agrochemical industries.
Natural preservatives are being extensively investigated for their potential industrial applications in foods and other products. In this work, an essential oil (Thymus daenensis) was formulated as a water-dispersible nanoemulsion (diameter = 143 nm) using high-intensity ultrasound. The antibacterial activity of the essential oil in both pure and nanoemulsion forms was measured against an important food-borne pathogen bacterium, Escherichia coli. Antibacterial activity was determined by measuring the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibacterial activity of the essential oil against E. coli was enhanced considerably when it was converted into a nanoemulsion, which was attributed to easier access of the essential oils to the bacterial cells. The mechanism of antibacterial activity was investigated by measuring potassium, protein, and nucleic acid leakage from the cells, and electron microscopy. Evaluation of the kinetics of microbial deactivation showed that the nanoemulsion killed all the bacteria in about 5 min, whereas only a 1-log reduction was observed for pure essential oil. The nanoemulsion appeared to amplify the antibacterial activity of essential oils against E. coli by increasing their ability to disrupt cell membrane integrity.
The essential oils of different parts of Platycladus orientalis (Cupressuceae) were examined for their potential antioxidant activity. The compositions of the essential oils of the plant were studied qualitatively and quantitatively by GC and GC-MS. The main components of the essential oils as well as positive controls were subjected to antioxidant testing. Different methods of, rapid TLC screening, diphenylpicrylhydrazyl (DPPH) assay, desoxyribose assay, assay for site-specific reaction and non-enzymatic lipid peroxidation were used to evaluate the antioxidant activity of the oils and various Positive controls. Positive controls were quercetin, vitamin E, vitamin C, dimethylsulfoxide (DMSO) and buthylhydroxytoluene (BHT). a-Pinene, ß-pinene, sabinene, limonene, À-3-carene and terpinolene were the major constituents of these essential oils. The tested compounds mainly showed antioxidant activity when two different rapid TLC screening methods used to evaluation the antioxidants activity. The abilities of the volatile oils to act as nonspecific donors for hydrogen atoms were checked in the diphenylpicrylhydrazyl, DPPH, assay. In this method the strongest effects were shown by the oil of leaves of P. orientalis. In deoxyribose degradation assay, most of the tested compounds showed some antioxidant activity. In non-enzymatic lipid peroxidation test, the oil obtained from leaves of P. orientalis showed strongest antioxidant activity. The results of the study indicate that the essential oils extracted from different parts of P. orientalis, main components of the oils and positive controls show different antioxidant activity when they tested by different antioxidant methods.
Heartwood samples from Juniperus virginiana L. were extracted with liquid carbon dioxide, and the bioactivity of carbon dioxide-derived cedarwood oil (CWO) toward several species of ants and cedrol toward ticks was determined. Repellency was tested for ants, and toxicity was tested for ticks. Ants in an outdoor bioassay were significantly repelled by the presence of CWO on a pole leading to a sugar-water solution. Similarly, CWO was a significant repellent barrier to red imported fire ants and prevented them from finding a typical food source. Black-legged tick nymphs exhibited dosage-dependent mortality when exposed to cedrol and at the highest dosage (i.e., 6.3 mg/ml) tested, the cedrol killed 100% of the ticks. These repellency and toxicity results together demonstrate a clear potential for the use of CWO as a pest control agent.
Many food products such as ice cream, yoghurt, and mayonnaise are some examples of emulsion-based food. The physicochemical properties of emulsions play an important role in food systems as they directly contribute to texture, sensory and nutritional properties of food. One of the main properties is stability which refers to the ability of an emulsion to resist physical changes over time. The aim of the present work was to analyze the effect of processing conditions and composition on sodium caseinate (NaCas) emulsions stability. The main destabilization mechanisms were identified and quantified. The relationship between them and the factors that influence them were also investigated. Emulsions stabilized with NaCas were prepared using an ultrasound liquid processor or a high pressure homogenizer. Stability of emulsions was followed by a Turbiscan (TMA 2000) which allows the optical characterization of any type of dispersion. The physical evolution of this process is followed without disturbing the original system and with good accuracy and reproducibility. To further describe systems, droplet size distribution was analyzed with light scattering equipment. The main mechanism of destabilization in a given formulation depended on different factors such as NaCas concentration, droplet size or processing conditions. The rate of destabilization was markedly lower with addition of sugar or a hydrocolloid to the aqueous phase. Xanthan (XG) and locust bean (LBG) gums produced an increase in viscosity of the continuous phase and structural changes in emulsions such as gelation. Sugars interacted with the protein decreasing particle size and increasing emulsion stability. The stability of caseinate emulsions was strongly affected not only by the oil-to-protein ratio but also by processing conditions and composition of aqueous phase. The structure of the protein and the interactions protein–sugar or the presence of a hydrocolloid played a key role in creaming and flocculation processes of these emulsions.
Juniperus communis leaf oil, J. chinensis wood oil, and Cupressus funebris wood oil (Cupressaceae) from China were analyzed by gas chromatography and gas chromatography-mass spectrometry. We identified 104 compounds, representing 66.8-95.5% of the oils. The major components were: α-pinene (27.0%), α-terpinene (14.0%), and linalool (10.9%) for J. communis; cuparene (11.3%) and δ-cadinene (7.8%) for J. chinensis; and α-cedrene (16.9%), cedrol (7.6%), and β-cedrene (5.7%) for C. funebris. The essential oils of C. funebris, J. chinensis, and J. communis were evaluated for repellency against adult yellow fever mosquitoes, Aedes aegypti (L.), host-seeking nymphs of the lone star tick, Amblyomma americanum (L.), and the blacklegged tick, Ixodes scapularis Say, and for toxicity against Ae. aegypti larvae and adults, all in laboratory bioassays. All the oils were repellent to both species of ticks. The EC(95) values of C. funebris, J. communis, and J. chinensis against A. americanum were 0.426, 0.508, and 0.917 mg oil/cm(2) filter paper, respectively, compared to 0.683 mg deet/cm(2) filter paper. All I. scapularis nymphs were repelled by 0.103 mg oil/cm(2) filter paper of C. funebris oil. At 4 h after application, 0.827 mg oil/cm(2) filter paper, C. funebris and J. chinensis oils repelled ≥80% of A. americanum nymphs. The oils of C. funebris and J. chinensis did not prevent female Ae. aegypti from biting at the highest dosage tested (1.500 mg/cm(2) ). However, the oil of J. communis had a Minimum Effective Dosage (estimate of ED(99) ) for repellency of 0.029 ± 0.018 mg/cm(2) ; this oil was nearly as potent as deet. The oil of J. chinensis showed a mild ability to kill Ae. aegypti larvae, at 80 and 100% at 125 and 250 ppm, respectively.
In most of the recent research on emulsions related to food products containing protein-polysaccharide interactions established via the Maillard reaction have been used as emulsifiers. Key challenges in such studies include long reaction times, uncontrollable extent of reaction, and protein denaturation and aggregation. The living cell is inherently crowded molecularly with biomacromolecules, occupying 20-40% of the total volume. In this study, to mimic cellular crowding conditions, we have used polyethylene glycol as a chemical crowding agent. The degree of glycation and the results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) indicated that a crowding environment triggers glycosylation and that the glycosylation degree gradually increases (p < 0.05) with increasing PEG concentration, which shortens the reaction time. The surface hydrophobicity of soybean protein isolate (SPI) significant decreased (p < 0.05), and the protein structure gradually unfolded from a helix to a random coil to prevent aggregation of SPI in the crowded environment. The solubility and the emulsifying and antioxidant properties improved upon adding the crowding reagent PEG. The chemical, freeze-thaw, and thermal stabilities of the nanoemulsion-stabilized SPI-dextran conjugate improved with increasing PEG concentration. However, the crowding environment had no effect on the salt stability of nanoemulsions.
Commercial products with specific textures and rheological properties can be made by controlling the processing variables by evaporation. In this research, we investigate the effect of evaporation time on rheological properties, DSD, microstructure and physical stability of biodegradable emulsions formulated with rosemary oil and Appyclean 6548, an alkyl polypentoside surfactant derived from wheat straw. Results showed that the rheological properties of emulsions depend greatly on time of evaporation and aging time. This method makes it possible to improve the viscosity and viscoelasticity compared with emulsions without evaporation. The main destabilization process was flocculation. Emulsions undergoing higher evaporation time also exhibited coalescence. In conclusion, rosemary nanoemulsions obtained by vacuum evaporation showed high stability and great resistance against creaming, making these appropriate for use in functional foods or cosmetic products.
This study fabricated N-(azobenzene-4-oxy-2-hydroxypropyl)-N-(alkyloxy-2-hydroxypropyl) aminopropyl sulfonic acid sodium salt (GnAZAS, n = 6, 8, and 12), a new photoresponsive anionic surfactant, through a simple, high-yield process involving ring-opening reactions of alkylglycidyl ether containing azobenzene and epoxide. The fabricated trans-GnAZAS can be transformed into 92.5% cis upon irradiation with 350 nm UV light, and was converted reversibly into 74% trans under irradiation with 450 nm visible light. Photoisomerization causes changes in the surface activity of surfactants. The critical micelle concentration (CMC) of the trans isomer of G12AZAS was 1.45 × 10⁻⁴ mol/L and the value of the 92.5% of cis isomer is 2.84 × 10⁻⁴ mol/L. Surface activity can be controlled by light in the range between the two CMC values, and the CMC difference for cis and trans forms of GnAZAS increased proportionately to the alkyl chain length. The minimum average area per molecule ( Amina/w ) of trans-G12AZAS is 1.14 nm². This becomes 1.20 nm² when converted to the cis form. The Amina/w is determined by structural differences between trans and cis isomers. In addition, this study examined the fabricated azobenzene surfactant in terms of emulsion stability, foaming power, and Turbiscan Stability Index (TSI), and compared it to commercialized surfactants LAE-9 and SLES-3.
This study investigated the effects of high-power ultrasound (HPU, 0-45 ℃, 242-968 W/cm², 2-16 min) on the rheological properties of strawberry pulp. Following the HPU treatment, the strawberry pulp exhibited an increase in apparent viscosity, storage modulus (G'), and loss modulus (G“). The water-soluble pectin (WSP), pectin methylesterase (PME) activity, and free calcium ions (Ca²⁺) of the strawberry pulp after HPU treatment were investigated to determine a possible reason for this phenomenon. HPU caused a significant decrease in the degree of esterification (DE), molecular weight (Mw), and particle size of strawberry WSP, but no significant changes were evident in the galacturonic acid (GalA) content and the zeta (ζ)-potential (P＞0.05), resulting in decrease in the apparent viscosity. Moreover, the largest reduction of PME activity was 22.6% after HPU treatment at 605 W/cm² and 45 ℃ for 16 min, indicating that the PME was resistant to the HPU treatments. The free Ca²⁺ content in the strawberry pulp was significantly decreased after exposure to HPU (P＜0.05). The maximal reduction of 52.01% in the free Ca²⁺ was achieved at 605 W/cm² and 45 ℃ for 16 min. The overall results indicated that the high residual activity (RA) of PME after HPU might induce the low esterification of WSP, while HPU promoted the interaction of free Ca²⁺ and low-methylated pectin, to form the network structure of Ca²⁺-low-methylated pectin, resulting in an increase in viscosity in the complex strawberry system.
Turbidity is used as a surrogate for suspended sediment concentration (SSC), and as a regulatory tool for indicating land use disturbance and environmental protection. Turbidity relates linearly to suspended material, however, can show non-linear responses to particulate organic matter (POM), concomitant with changes in particle size distribution (PSD). In the paper the influence of ultra-fine particulate matter (UFPM) on specific turbidity and its association with POM in suspended sediment are shown for alpine rivers in the Southern Alps of New Zealand. The approach was twofold: a field-based investigation of the relations between SSC, POM, and turbidity sampled during event flow; and experimental work on hydrodynamic particle size effects on SSC, POM, PSD, and turbidity. Specific turbidity changes over event flow and are sensitive to increasing proportional amounts of sand, UFPM, and POM in suspension. Furthermore, the UFPM is the size fraction (<6 mm) where POM increases. The implications of the current study are that the slopes of turbidity-SSC relations are undesirable in locations that may be dominated by cyclic release of POM or distinct pulses of fine-grained material. At locations where the turbidity-SSC slopes approximate 2, the POM proportion is usually <10% of the total suspended load. However, when turbidity-SSC slopes are <1 this is likely caused by high amounts of side-scatter from UFPM concomitant with higher proportions of POM. Thus, the use of turbidity as a proxy for determining SSC may have serious consequences for the measurement of representative suspended sediment data, particularly in locations where POM may be a significant contributor to overall suspended load.
The aim of this work was to study the stability of oil-in-water emulsions formed by corn oil with rice bran protein and rice bran protein-catechin complexes, at a (+)-catechin concentration of 0.05%–0.25% (w/v). The experimental results showed that the addition of (+)-catechin decreased the α-helix and β-sheet content to 10.15% and 36.68%, respectively. The surface hydrophobicity increased, and the oil-water interfacial tension decreased to 11.52 mN/m. The emulsions using the rice bran protein-catechin complex (0.15%, w/v) showed the smallest droplet size and the best emulsifying properties. However, a (+)-catechin concentration above 0.20% (w/v) negatively affected the emulsion stability, with increasing droplet size and decreasing absolute ζ-potential values due to protein aggregation. Rheological behavior analyses suggested that the rice bran protein-catechin complex emulsion had higher viscosity and viscoelasticity than the emulsion formed with the control rice bran protein.
Ethnopharmacological relevance:
Zingiber officinale (ginger) is a perennial herbaceous plant native in tropical Asia and generally cultivated in most American tropical countries with widespread use in popular medicine. Ginger essential oil (GEO) has been reported to exhibit several biological activities, such as antimicrobial.
Aims of the study:
The aim of this study was to determine the composition and the property of GEO and related fractions against Mtb and NTM, as well as their cytotoxicity.
Methods and materials:
GEO was obtained by hydrodistillation and fractionation was performed. Chemical characterization of GEO and fractions were carried out by gas chromatography/mass spectrometry. The antimycobacterial activity was evaluated by resazurin microtiter assay plate and broth microdilution method for Mtb and NTM, respectively. The cytotoxicity in Vero cells was assessed by MTT colorimetric assay.
Results:
The analyses showed 63 compounds in the GEO sample, characterized by a high number of monoterpenes and sesquiterpenes. GEO fractionation rendered 11 fractions (FR1 to FR11). GEO and fractions minimum inhibitory concentration ranged from 31.25 to >250 μg/mL against Mtb and from 15.6 to >250 μg/mL against NTM. GEO showed better activity against NTM, M. chelonae, and M. abscessus sub. massiliense, than the semi-pure fractions. One fraction (FR5), containing γ-eudesmol as the main compound, was the most active against Mtb and NTM. The GEO and semi-pure fractions cytotoxicity assay showed CC50 63.3 μg/mL, and 36.3-312.5 μg/mL, respectively.
Conclusions:
In general, GEO showed a mix of monoterpenes and sesquiterpenes and a better antimycobacterial activity than the semi-pure fractions. Cytotoxic effects of GEO and its fractions should be better investigated.
In this study, encapsulation of garlic essential oil (GEO) in nanophytosomes as a novel phytoconstituents delivery system was performed via three different methods. The physicochemical characterization of nanophyto-somes were studied by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) and also antioxidant activity, physical stability and antibacterial effects against food-borne pathogens i.e. Escherichia coli and Staphylococcus aureus were investigated. Optimized GEO nanophytosomes showed promising results with the size of 115 nm, loading capacity of 40%. The information on FT-IR indicated that the GEO were loaded into structure of nanophytosomes. Finally, an increase in antibacterial effect was observed for GEO nanophytosome. Yogurt was selected as a food model for sensory properties evaluation and the results showed insignificant difference among sample containing GEO loaded nanophytosomes and control. It can be concluded that GEO-nanophytosomes may be offered as an efficient natural food preservative .
Background
Pickering emulsions are stabilized by solid particles. Among the particles as emulsifiers, starch based particles have gained research focus. Starch is GRAS, non-allergenic, cheap, and abundant. Products of starch based Pickering emulsions are seen to be more “natural”. However, the information regarding starch based Pickering emulsions is scattered.
Scope and approach
This review summarizes the recent advances in starch modifications for Pickering emulsion fabrication. Physicochemical properties of starch based Pickering emulsions, including droplet size, in vitro digestibility, rheological properties, storage and process stability, and microstructure are described. Different applications of starch based Pickering emulsions are presented. Research gaps on Pickering emulsions are suggested.
Key findings and conclusions
Native starch granules are modified to become efficient emulsifiers in Pickering emulsions. The starch modifications include octenyl succinic anhydride (OSA)-modification, hydrolysis, milling, non-solvent precipitation, ultrasound and high pressure treatments. The resulting Pickering emulsions have a droplet size of ∼1–100 μm which depends on emulsion composition, starch type, pH, and ionic strength. Different applications of the Pickering emulsions include Pickering emulsion polymerization, encapsulation of bioactive components for functional food systems, and formulation of emulsion-type products such as mayonnaise. It can be concluded that starch based Pickering emulsions have potential to be used in various food applications with improved functionalities.
Clove (Syzygium aromaticum, L.) essential oil is known for its antimicrobial activity against several pathogenic bacteria. Encapsulation of clove oil was proposed as a mean to disguise its strong odor that limits its uses in food industry. Thus, the aim of this study was extraction, encapsulation and assessment of the antimicrobial and antioxidant potential of clove essential oil. The essential oil showed high DPPH scavenging capacity and low hydroxyl radical inhibition. Clove essential oil showed in vitro inhibitory and bactericidal effect against S. aureus, E. coli, L. monocytogenes and S. Typhimurium. In addition, in situ antimicrobial activity of clove oil against S. aureus was superior to nitrite. The essential oil particles encapsulated with sodium alginate and emulsifiers, showed high encapsulation efficiency, low antioxidant activity and strong antimicrobial inhibition. Similar bacterial growth was observed in meat-like products after addition of either particles or nitrite.
To respond to the market demand for consistency of supply and quality, there are current efforts to develop junipers as agricultural crop for the production of juniper galbuli (berries). However, comparative data on the galbuli essential oil (EO) composition and bioactivity of different juniper species is limited. The objective of this study was to evaluate the EO composition, antimicrobial and antioxidant activity of the galbuli of the six juniper species naturally distributed in Bulgaria: Juniperus communis L. (common juniper), J. oxycedrus L. (red juniper), J. sibirica Burgsd. (Siberian juniper), J. sabina L. (Cossack juniper), J. pygmaea C. Koch. (Alpine juniper), and J. excelsa M. Bieb. (Gracian juniper). The EO content of the galbuli of the six juniper species varied from 0.47% (in J. sibirica) up to 1.6% (in J. sabina). The oil profile of the galbuli was also different among species. Differences and similarities in the groups of terpenes were established between the six juniper species. The three oil constituents with the highest concentration (in descending order) in the galbuli of each of the species were as follows: for J. oxycedrus: β-Myrcene, α-Pinene, and Germacrene D; for J. communis: α-Pinene, Germacrene D, β-Myrcene; for J. excelsa: α-Pinene, α-Cedrol, Germacrene D; for J. sibirica: α-Pinene, β-Myrcene, Germacrene D; for J. pygmaea: α-Pinene, Sabinene, β-Myrcene; and for J. sabina: Sabinene, α-Pinene, Terpinene-4-ol. Overall, the antioxidant capacity of the six oils was as follows: J. sibirica > J. communis = J. excelsa. Out of the six EO, J. oxycedrus galbuli EO was the most effective against Clostridium perfringens, J. communis against Candida clabrata and J. oxycedrus against Staphylococcus aureus. The antioxidant capacity of the juniper galbuli oils were positively affected by the concentrations of β-Elemene, γ-Elemene, and τ-Muurolol. Positive relationships were found between the concentrations of some constituents with the antimicrobial activity of juniper EO against Staphylococcus aureus, Bacillus cereus, Yersinia enterocolitica, Clostridium perfringens, and Candida glabrata. The results contribute to further understanding of juniper galbuli EO, can be used by industry utilizing juniper EOs, and may help with policy making processes with respect to conservation and agriculture.
The aim of this study was to compare the emulsifying capacity and stability of soybean oil-in-water (O/W) Pickering emulsions stabilized by different areca taro starches (native starch, OSA esterified starch, ball-milled starch, and compound modified starch with ball-milling and OSA), and investigate the stability mechanism of Pickering emulsions. It was found that the compound modified starch showed strong surface activity and high emulsion viscosity, resulted in the best emulsifying capacity and stability. It could be clearly seen that the starch particles adsorbed at the oil-water interface of droplets to form physical barriers, and the upper and middle emulsion phases were uniform and stable after storage for 30 d. Thus, the ball-milling combined with OSA modification can be used as a viable and effective method to produce better starch-based particle emulsifiers.
In this study, emulsions were prepared through spontaneous emulsification, using three different citrus oils as the oil phase and Tween 80 as the surfactant. Utilizing 4% Tween 80, three types of citrus oil emulsions were prepared with small particle size, monomodal distribution and high transmission. After 24 h, each emulsion exhibited different degrees of gravitational separation. Mandarin oil emulsions were the most unstable, showing coalescence of small droplets with an obvious cream layer formed at 9 h. Bergamot oil emulsions possessed small droplets with the best stability over 24 h, due to their relatively polar components (e.g. linalyl acetate) and water-insoluble constituents (e.g. γ-terpinene). These results suggest that the emulsifying properties and instability mechanism of citrus oil emulsions are strongly dependent on the inherent properties and composition of citrus oils. This study is significant for the development of an effective strategy to improve the stability of citrus oil-based colloidal systems.
The increasing demand for sustainable packaging materials with minimal ecological footprint, compatible cost and stable shelf-life has led to a growing interest in biodegradable or compostable cellulosic packaging materials. Since cellulosic fibers are prone to termite (Reticulitermes flavipes) attack, a study was conducted to identify natural and safe termiticides that can be applied to 100% biodegradable composites derived from lignocellulosic fibers and fungus mycelium. The composite material is a patented technology, developed by Ecovative Design LLC (Green Island, NY). Biocomposite boards of two densities were manufactured using kenaf, hemp and corn fibers and bonded by three different strains of fungi Daedaleopsis confragosa, Ganoderma resinaceum, and Tramates versicolor. The resultant biocomposite boards were evaluated for termite resistance using four termiticides: vetiver oil (Vetiveria zizanioides), guayule resin (Parthenium argentatum), cedar oil (Juniperus virginiana), and borax. The treated boards were evaluated for termite resistance in accordance with ASTM D3345-01. The results showed variable impact of different types of termiticides on fungus mycelium bonded cellulosic biocomposites. A heavy to complete mortality was observed in guayule resin and vetiver treated boards. Borax was least effective as a termiticide. Kenaf and hemp boards treated with guayule resin showed maximum repellency to termites, followed by vetiver oil. The weight loss for treated and untreated samples ranged between 17.4%–33.7%, and 19.9%–55.8% respectively. The findings of this study show that vetiver and cedar natural oils and guayule resin can be used as an effective treatment on mycelium bonded cellulosic composites to improve their termite resistance.
In this work, the nanoemulsion of essential oil from Citrus medica L. var. sarcodactylis was prepared using a spontaneous emulsification method. Meanwhile, the effect of nanoemulsification on the antioxidant, antibacterial and antibiofilm activity of essential oil was evaluated. GC–MS analysis indicated nineteen compounds in the essential oil, and the essential oil was dominated by d-Limonene (50.04%). The minimum and stable droplets (73 nm) of essential oil nanoemulsion were formulated when the concentration of essential oil in oil phase was 50% (w/w). The hydroxyl radicals, DPPH radicals scavenging ability, iron reducing power, antibacterial and antibiofilm activity of nanoemulsified essential oil were significantly higher than those of pure essential oil at same concentration. Moreover, the nanoemulsified essential oil exhibited higher inhibitive effect on the bacteria in tofu than pure essential oil. Therefore, nanoemulsification significantly enhanced the antioxidant, antibacterial and antibiofilm activity/efficiency of essential oils, which will promote the abroad utilization of essential oils.
The purpose of this study was to determine the chemical composition and antibacterial activity of the Moroccan Cedarwood essential oil. The sawdust samples of Cedrus atlantica were collected from Azrou, located in the heart of The Middle Atlas region of Morocco. The plant samples were subjected to hydrodistillation for eight hours. The oils were then analysed by Gas Chromatography equipped with flame ionization detector (GC-FID) and Gas chromatography coupled with Mass spectrometry (GC-MS). The antimicrobial activities were tested in vitro on gram-negative bacteria Escherichia coli and Salmonella, as well as gram-positive Staphylococcus aureus, Bacillus subtilis and Bacillus cereus using the agar diffusion assay/aromatogramme and minimum inhibitory concentration (MIC). Three bacterial strains (Escherichia coli, Bacillus subtilis and Bacillus cereus) were found to be sensitive to cedarwood essential oil and showed effective bactericidal activity with a Minimum Inhibitory Concentration of 0,4 μl/ml for Escherichia coli and Bacillus cereus, and 0,2 μl/ml for Bacillus subtilis.
The emulsifying properties of Brea gum (BG), the exudate from Cercidium praecox, were studied in comparison to gum Arabic (GA). Droplet size distributions, rheological properties and stability of corn oil emulsion stabilized with BG and GA solutions were analyzed. The results showed that an increase in BG concentration led to a decrease in Z-average diameter and to an increase in emulsion apparent viscosity and stability. All emulsion flow curves presented shear-thinning behavior at low shear rates and Newtonian plateau at high shear rates. The mechanical spectra showed droplets tending to arrange as a network in the emulsions which was related to the high stability. BG emulsion presented higher viscosity and stability than GA emulsion at the same concentration suggesting that BG could replace GA in some industrial applications.
Blended cloves/cinnamon essential oil nanoemulsions were prepared using Tween 80 and ethanol as surfactant and cosurfactant respectively. The preparation process was optimized via a pseudo-ternary phase diagram. The nanoemulsion showed a steady state with an average particle size of 8.69 nm under the surfactant to cosurfactant ratio (Km) of 3:1 and oil to the mixed surfactant/cosurfactant ratio of 1:9. The nanoemulsion was stable after centrifuging at 10,000 rpm for 20 min, stored at 60 °C for 1 month, or even heated at 80 °C for 30 min, respectively. Compared with the non-nanoemulsion counterparts, the nanoemulsion showed higher antimicrobial activity against four tested microorganisms of Escherichia coli, Bacillus subtilis, Salmonella typhimurium, and Staphylococcus aureus, even at far lower concentrations. Furthermore, the addition of the cloves/cinnamon nanoemulsion in a model food of mushroom sauce did not alter its major flavor, except offered some attractive fragrant flavors. This research suggested that the blended cloves/cinnamon essential oil nanoemulsions have the potential to be developed as a natural antimicrobial agent in food industry.
Green coffee oil and modified starch were recently found to have an enhanced protection effect against UV radiation. Therefore, this work aimed to develop an innovative sunscreen formulation based on Pickering emulsions concept, i.e., surfactant-free emulsions stabilized by physical UV filters associated natural oils as a key strategy for prevention against UV-induced skin damage. The Pickering emulsions of different compositions were characterized in terms of pH, mechanical, physical and microbiological stability by a thorough pharmaceutical control. In addition, the sun protection factor (SPF) as well as the in vitro and in vivo biological properties of the final formulations, including Episkin®, HRIPT and sunscreen water resistance. Formulation studies demonstrated the addition of physical UV filters was beneficial, leading to the inclusion of ZnO and TiO2 to ensure a high SPF against UVA and UVB, respectively. Although starch particles presented no intrinsic photoprotection properties, they proved to be a SPF promoter by a synergistic effect. Green coffee oil was the selected natural oil due to the highest SPF, when compared to other natural oils tested. Besides the excellent sunscreen activity confirmed by in vitro and in vivo results, the final formulations proved to be also suitable for topical use according to the rheological assessment and stability throughout the study period (3months). In conclusion, the combination of three multifunctional solid particles and green coffee oil, contributed to achieve a stable and effective innovative sunscreen with a wide range of UV radiation protection.
In this work, the effects of combining a surfactant/alkali on the stability of heavy-oil-in-water emulsions are analyzed by use of bottle testing, spinning-drop interfacial-tension (IFT) meters, microscopes, conductivity meters, zeta-potential analyzer Turbiscan laboratory expert stabilizer, and Anton Paar rheometer. The experimental results showed that the formulated surfactant (BS- 12 and OP-10) had an optimal mass ratio (1:2), and the water-separation rates initially decreased sharply as the concentrations of the surfactant increased, before decreasing moderately until reaching a minimum value. The formulated alkali solution exerted a positive synergistic effect in tandem with the surfactant at low alkali concentrations. In this way, an increasing number of petroleum soaps are produced by reactions between the alkali solutions and the active components in heavy crude oil. However, the effect was reversed at high alkali concentrations, where the compression of the alkali on the electric double layer was more significant. Images of the emulsions taken with a microscope showed that the sizes of the oil droplets were the smallest when the alkali concentration was 0.2% and mass ratio of NaOH and TEA (triethanolamine) was 1:1, which indicated that the amount of petroleum soap produced reached the maximum at this point. In addition, TEA, as a type of surface-active molecule, can form cross-multiple adsorption and hydrogen-bonding structure with surfactant and petroleum soap at the water/oil interface. When the oil/water ratio was 7:3, the water-separation rate reached its lowest point 5.33% for 3 hours. In addition, the emulsion stabilized by the surfactant and the compositional alkali possesses salt tolerance and temperature resistance. When the concentration of the bivalent salt (CaCl2 and MgCl2) increased to 0.01molL⁻¹, the water-separation rate was less than 20%, and when the temperature increased from 30 to 60°C, the growth of back-scattering (BS) value was less than 2%.
To control the decay of fresh vegetables or fruits after harvest and overcome higher costs using a natural agent, synergistic antifungal effects were studied in tomatoes and their main decay fungi Fusarium solani and Rhizopus stolonifer. After screening 56 groups with a checkerboard method based on 11 natural agents, only one combination of thymol and salicylic acid (STSA) had a synergistic effect on both fungi. Their average minimal inhibitory concentration (MIC) values decreased significantly to 0.43 fold compared with the single agents tested. Their mycelial growth was completely inhibited; the inhibition rates of spore germination exceeded 96% at 0.5, 1, and 2 MIC. The protective and therapeutic effects were found to be dose-dependent during exposure; the former was always better than the latter against both fungi at any tested concentration in wound-inoculated tomatoes, and phytotoxicity occurred only when the concentration of STSA reached 2 MIC in naturally stored fruit. Consumer evaluation showed that the natural, non-inoculated tomatoes treated with 1 MIC and the wound-inoculated tomatoes treated with 2 MIC were both acceptable. The in vitro and in vivo results show that a combination of thymol and salicylic acid could be developed as a control measure and could reduce costs.
Food spoilage and foodborne illnesses are two global challenges for food manufacturers. Essential oils are natural antibacterials that could have a potential for use in food preservation. Unfortunately high concentrations are needed to obtain the desired antibacterial effect, and this limits their use in food due to their adverse organoleptic properties. Encapsulation could make essential oils more effective by concentrating them in the aqueous phase of the food matrix where the bacteria are present. Here we tested encapsulation of the essential oil isoeugenol in spray-dried emulsions as a means of making isoeugenol a more effective antibacterial for use in food preservation. We used β-lactoglobulin and n-OSA starch as emulsifiers, and some emulsions were coated with positively charged chitosan to promote the contact with bacteria through electrostatic interactions. The antibacterial efficacy was quantified as the minimal bactericidal concentration in growth media, milk and carrot juice. The emulsion encapsulation system developed in this study provided high loading capacities, and encapsulation enhanced the efficacy of isoeugenol against Gram-positive and -negative bacteria in media and carrot juice but not in milk. Chitosan-coating did not enhance the efficacy further, possibly due to the aggregation of the chitosan-coated emulsions. The encapsulation system is easy to upscale and should be applicable for encapsulation of similar essential oils. Therefore, we believe it has potential to be used for natural food preservation.
The aim of this study was to develop a stable water emulsion-based phase change material (PCM), with low viscosity, for solar thermal applications. The effects of different non-ionic emulsifiers, including nine kinds of binary mixtures of Tweens and Spans, on the droplet diameter distribution, the apparent viscosity and the stability of the emulsions, were evaluated. There appeared to be an effective range for both the emulsifier concentration and the dispersed phase PCM content to maintain the stability and the fluidity of the emulsions. The emulsification process also played an important role in controlling the size distribution of the PCM droplets in the emulsions. Thermal analysis by differential scanning calorimetry indicated that the degree of supercooling of the emulsion increased with the droplet size decline and that dispersed nano SiO2 particles were effective as a nucleating agent to reduce supercooling. Multiple phase transitions were observed in the melting and the crystallisation processes of the PCM. The rheology characteristics and the long-term storage stability of the emulsions were also investigated and are discussed.
Cedrol, β-cedrene, and thujopsene are bioactive sesquiterpenes found in cedar essential oil and exert antiseptic, anti-inflammatory, antispasmodic, tonic, astringent, diuretic, sedative, insecticidal, and antifungal activities. These compounds are used globally in traditional medicine and cosmetics. The aim of this study was to investigate the inhibitory effects of cedrol, β-cedrene, and thujopsene on the activities of eight major human cytochrome P-450 (CYP) enzymes using human liver microsomes to assess potential β-cedrene-, cedrol-, and thujopsene–drug interactions. Cedrol, β-cedrene, and thujopsene were found to be potent competitive inhibitors of CYP2B6-mediated bupropion hydroxylase with inhibition constant (K i) values of 0.9, 1.6, and 0.8 μM, respectively, comparable with that of a selective CYP2B6 inhibitor, thioTEPA (K i, 2.9 μM). Cedrol also markedly inhibited CYP3A4-mediated midazolam hydroxylation with a K i value of 3.4 μM, whereas β-cedrene and thujopsene moderately blocked CYP3A4. Cedrol, β-cedrene, and thujopsene at 100 μM negligibly inhibited CYP1A2, CYP2A6, and CYP2D6 activities. Only thujopsene was found to be a mechanism-based inhibitor of CYP2C8, CYP2C9, and CYP2C19. Cedrol and thujopsene weakly inhibited CYP2C8, CYP2C9, and CYP2C19 activities, but β-cedrene did not. These in vitro results indicate that cedrol, β-cedrene, and thujopsene need to be examined for potential pharmacokinetic drug interactions in vivo due to their potent inhibition of CYP2B6 and CYP3A4.
Nanoemulsions are used as delivery systems in food, pharmaceutical, and personal care applications for a variety of lipophilic active components, e.g., antimicrobials, flavors, colors, preservatives, vitamins, nutraceuticals, and drugs. In this study, we examined the effect of system composition and preparation conditions on the production of edible nanoemulsions using spontaneous emulsification (SE). SE is a low-energy method that simply involves addition of an organic phase (oil + surfactant) into an aqueous phase. The influence of surfactant-to-oil ratio (SOR), surfactant type, surfactant location, and oil type were tested. The droplet size produced decreased with increasing SOR, and was smallest when the non-ionic surfactant Tween 80 was used. Smaller droplets were formed when the surfactant was initially dispersed in the oil phase rather than the aqueous phase. Ten food-grade oils were tested and we found that droplet size followed the order: medium chain triglycerides < flavor oils < long chain triglycerides. No correlation was found between droplet size and the physicochemical characteristics of the oil phase (refractive index, density, interfacial tension, and viscosity). Results obtained by spontaneous emulsification were correlated to those obtained by emulsion phase inversion on similar systems suggesting a common underlying physicochemical mechanism.
Water content of W/O crude oil emulsion and temperature have great influence on stability of the W/O crude oil emulsion and the subsequent demulsification process especially for oil-water treatment centers using a two-step sedimentation demulsification process in Jilin oilfield. Electrical microscope and Turbiscan stability analyzer were employed to investigate the influence of water content and temperature on stability of synthetic W/O emulsion. The results show that the average water droplets size decreases when water content decreases, the emulsion stability decreases when water content or holding temperature increases, and the emulsion stability constant and the temperature have a linear relationship.
Consumption of plant phenolics in the daily diet has been recognised as lowering the risk of aging-associated diseases. A total of 11 cold-field fruits in China were evaluated for total contents of phenolics, flavonoids and anthocyanins, and antioxidant and antiproliferation activities. Total phenolic contents of the fruits extracts had a positive correlation with antioxidant activity (R2>0.7112). Among the 11 fruits, the extracts of raspberry had the highest capacities for scavenging DPPH (EC50 25.6±0.51μM TE/g FW) and ABTS+ (EC50 63.6±1.67μM TE/g FW). Proliferation of HepG2 and HT-29 cells was significantly inhibited in a dose-dependent pattern after exposure to the fruit extracts, among which lingonberry and rowanberry exhibited the highest antiproliferative activities. These results provide new knowledge on health functions of fruits and the fruits with high antioxidant contents are recommended for potential health benefits.
Maillard reaction products (MRPs) were prepared by reacting casein peptides with different concentrations of glucose at 80 °C for up to 12 h. The chemical properties of MRPs and their effects on lipid oxidation in fish oil-in-water emulsions were investigated. Increasing browning development and absorbance in 294 nm in the MRPs caused an increase in DPPH radical scavenging, but a decrease in iron chelation, which could be related to the loss of free amino groups in the peptides. The MRPs produced with longer reaction time or higher glucose concentrations were less effective in inhibiting lipid oxidation in emulsions at pH 7.0 compared to casein peptides alone. However, the antioxidant activity of MRPs in emulsions at pH 3.0 was not decreased by prolonged heating. The bitterness of MRPs was less than that of the original casein peptides, and bitterness decreased with increasing heating time and glucose concentrations. Therefore, the Maillard reaction was a potential method to reduce the bitterness of casein peptides while not strongly decreasing their antioxidant activity.
The consequences of the instability mechanism partial coalescence in oil-in-water food emulsions show a discrepancy. On the one hand, it needs to be avoided in order to achieve an extended shelf life in food products like sauces, creams and several milk products. On the other hand, during the manufacturing of products like ice cream, butter and whipped toppings partial coalescence is required to achieve the desired product properties. It contributes to the structure formation, the physicochemical properties (stability, firmness,...) and the sensory perception, like fattiness and creaminess of the final food products. This review critically summarises the findings of partial coalescence in oil-in-water emulsions in order to provide insight in how to enhance and retard it. Next to the pioneering work, a large set of experimental results of more recent work is discussed. First, the general mechanism of partial coalescence is considered and a distinction is made between partial and 'true' coalescence. The main differences are: the required solid particles in the dispersed oil phase, the formation of irregular clusters and the increased aggregation rate. Second, the kinetics of partial coalescence is discussed. In more detail, potential parameters affecting the rate of partial coalescence are considered by means of the encounter frequency and capture efficiency of the fat globules. The flow conditions, the fat volume fraction and the physicochemical properties of continuous aqueous phase affect both the encounter frequency and capture efficiency while the actual temperature, temperature history and the composition and formulation of the emulsion mainly affect the capture efficiency.
Chemical analysis of the essential oil of Juniperus thurifera wood led to the identification of fifty-eight sesquiterpene compounds, of which twenty-eight have been isolated, two of them being new natural cedrane derivatives (1 and 2). Their structures were established on the basis of 1D NMR and 2D NMR spectra. The antimicrobial activities of different pure compounds of this oil were tested against nine microorganisms (Gram-positive and Gram-negative bacteria, and yeasts). Seven of the tested compounds exhibited a relevant activity, with the known alpha- and beta-cedrenes and sesquithuriferol showing minimum inhibitory concentrations of 3.06 microg/mL against Bacillus subtilis and Proteus sp.