Limonene Content Research Articles

Development and validation of mathematical models for testing antifungal activity of different essential oils against Candida species

ObjectiveThe upward trend in using plant materials introduced essential oils (EOs) as a valuable, novel, bioactive antifungal agent and as an alternative to standard treatment protocol of denture stomatitis caused by Candida species. Therefore, the aim was to evaluate the antifungal activity of different EOs and to present the response surface methodology (RSM) and artificial neural network (ANN) as possible tools for optimizing and predicting EOs antifungal activity. MethodsMinimum inhibitory concentration (MIC) and Minimum fungicidal concentration (MFC) of the EOs against 3 species Candida spp. (C. albicans, C. tropicalis, C. glabrata) isolated in patients with DS were determined, together with optimization and prediction based on non-terpene and terpene content in EOs, using two mathematical models RSM and ANN-GA. ResultsThe highest concentrations of EO M. alternifolia inhibited (1.6–2.8 μg/ml) and fungicided (3.5–6.0 μg/ml) all three investigated Candida spp. while the lowest concentrations of EO C. limon inhibited (0.2 – 0.5 μg/ml) and fungicided (0.6–1.1 μg/ml). Among the three types of Candida, C. glabrata was the most sensitive. The RSM modelling proved that MICs and MFCs statistically depend on non-terpene and terpene content in different EOs (<0.0001). Both models showed that a citrus oil (EO C. limon) with 89% content of terpenes and limonene as major constituent was more antifungal efficient. ConclusionsThe investigated EOs showed a broad spectrum of anticandidal activity, also confirmed using the RSM and ANN-GA models. Since EOs can be cytotoxic in higher concentrations, models may be used for qualitative and quantitative dosage predictions of the antifungal activity of EOs.

The terpene limonene induced the green mold of citrus fruit through regulation of reactive oxygen species (ROS) homeostasis in Penicillium digitatum spores.

Herein, the dosage effect of limonene on the P. digitatum spore germination and its regulatory mechanisms were investigated. Results showed that limonene only at low concentrations displayed a stimulatory role, with the optimal concentration being 0.25 μL/mL. GC-MS and GC analysis revealed that limonene contents remained relative stable and no evidence of transformation was observed at stimulatory concentrations. Metabolomics analysis showed that 61 metabolites including organic acids, amino acids, sugars, nucleosides, fatty acids, and their derivatives, were significantly changed (P < 0.05), suggesting the transitions between soluble sugars and energy-related metabolisms. Proteomic analysis demonstrated that proteins in energy-related pathways and ROS homeostasis were also influenced. These were further confirmed by the activities of catalase (CAT), superoxide dismutase (SOD), and glutathione-S-transferase (GST), the contents of reactive oxygen species (ROS), hydrogen peroxide (H2O2), and glutathione (GSH). Our present research indicates that ROS homeostasis is involved in the limonene induced spore germination of P. digitatum.

Glomus intraradices (N.C. Schenck &amp; G.S. Sm.) C. Walker &amp; A. Schuessle enhances nutrients uptake, chlorophyll and essential oil contents and composition in Anethum graveolens L.

Arbuscular mycorrhizal (AM) fungi are plant-root symbionts whose application in agriculture has been proven its efficiency. However, their application in medicinal plants and their impact on accumulation of essential oils (EO) is still limited. In order to investigate the effect of AM fungi (Glomus intraradices N.C. Schenck &amp; G.S. Sm.) C. Walker &amp; A. Schuessle) on nutrients uptake, biomass production, yield components, chlorophyll content, and EO content and composition in dill (Anethum graveolens L.), a field experiment was conducted as randomized complete block design with three replications. This medicinal plant was grown under AM fungi colonization and non-colonization treatments. Plant inoculation by mycorrhiza increased aerial tissues P and Fe concentrations. However, K, Ca, and Zn concentrations were not affected by AM colonization. The plants inoculated with AM significantly increased plant biomass, chlorophyll content, and EO content by 363 g m−2, 11.83 SPAD and 0.683 % in comparison with non-inoculated plants, respectively. Changes in EO composition were found in AM-colonized dill plants. The contents of myristicin, dill-ether and N-dihydrocarvone increased in EO obtained from AM-colonized plants, while AM colonization resulted in a lesser content of α-pinene, α-phellandrene, limonene, and β-phellandrene.

Qualitative and quantitative variations of the essential oils of Dracocephalum kotschyi Boiss. as affected by different drying methods

Using an appropriate drying method is the most important step in the postharvest processing of Dracocephalum kotschyi Boiss. to preserve its qualitative and quantitative essential oils. In this study, the effects of different drying techniques (sun, shade, conventional oven, vacuum oven, microwave, and infrared drying) were investigated on the essential oil content and composition of plants. Vacuum oven-drying at 40°C was the best method for the retention of the essential oils of the samples. The essential oil was relatively sensitive to temperature, so its content was decreased with increase in the drying temperature. The results showed that oxygenated monoterpenes represented the main chemical class of essential oil components. Although the highest content of α-pinene and geranyl acetate (as major compounds) was obtained by conventional oven-drying at 40°C, the highest content of limonene and α-terpineol was observed in the plants dried under the sun and by infrared drying at 0.5w/cm, respectively. Practical applications The results suggest that vacuum oven-drying could be the best method for obtaining the highest content of essential oils from Dracocephalum kotschyi Boiss along with its major bioactive components. In addition, the microwave drying method was known as the most desirable drying method with regard to the final color of the dried products.

Use of Orange Oil Loaded Pectin Films as Antibacterial Material for Food Packaging.

This study aims to develop orange oil loaded in thin mango peel pectin films and evaluate their antibacterial activity against Staphylococcus aureus. The mango peel pectin was obtained from the extraction of ripe Nam Dokmai mango peel by the microwave-assisted method. The thin films were formulated using commercial low methoxy pectin (P) and mango pectin (M) at a ratio of 1:2 with and without glycerol as a plasticizer. Orange oil was loaded into the films at 3% w/w. The orange oil film containing P and M at ratio of 1:2 with 40% w/w of glycerol (P1M2GO) showed the highest percent elongation (12.93 ± 0.89%) and the lowest Young’s modulus values (35.24 ± 3.43 MPa). For limonene loading content, it was found that the amount of limonene after the film drying step was directly related to the final physical structure of the film. Among the various tested films, P1M2GO film had the lowest limonene loading content (59.25 ± 2.09%), which may be because of the presence of numerous micropores in the P1M2GO film’s matrix. The inhibitory effect against the growth of S. aureus was compared in normalized value of clear zone diameter using the normalization value of limonene content in each film. The P1M2GO film showed the highest inhibitory effect against S. aureus with the normalized clear zone of 11.75 mm but no statistically significant difference. This study indicated that the orange oil loaded in mango peel pectin film can be a valuable candidate as antibacterial material for food packaging.

Essential oil extraction from herbs and their use in the food industry

Essential oil extraction of wild caraway and thyme was performed using a classical (HD) and microwave hydro-distillation (MWHD) and a laboratory supercritical fluid extraction (SFE) with a carbon dioxide as solvent. Our experiments demonstrated that the extraction yield of the essential oil performed in same conditions was influenced by the location of growth area; the maximum extraction yield of 10 ml 100 g-1 caraway was obtained from dried seeds collected from Csíkmadaras. This quantity far exceeded the yield of the Újtusnád samples. In the case of wild caraway (Carum carvi L.), the extraction method influenced thecomposition of the essential oil (carvone/limonene ratio), the highest limonene content being achieved by classical hydro-distillation. In the case of thyme, this effect was not detected, the thymol/carvacrol ratio was independent from the given extraction method. The obtained thyme essential oil possesses high antimicrobial activity demonstrated by agar diffusion test. The thyme extract provides a good protection against microorganisms collected on the surface of fresh vegetables following bacterial stains: Citrobacter portucalensis, Pseudomonas hunanensis, Pseudomonas baetica, Pseudomonas parafulva, Bacillus mojavensis and Enterobacter cloacae. Protective effect was also detected on the vegetable surface of by chitosan-based edible film coating during a 6-day-long storage period at a temperature of 4 °C. The caraway essential oil used as soft cheese seasoning with a direct, dilution-free method, proved to be unsuitable because the uneven distribution and confer a strong, unpleasant taste to the product in comparison with the ground wild caraway seed-dressed cheese.

Screening of Profiles of Essential Oils from the Aerial Parts of Sclerorhachis platy-rachis (Boiss.) Podlech ex Rech.f. Using Classical and Microwave-based Methods: Comparison with the Volatiles Using Headspace Solid-Phase Microextraction

Chemical profiles of the essential oils and volatile compounds from the aerial parts of Sclerorhachis platyrachis (Boiss.) Podlech ex Rech.f. obtained through hydrodistillation (HD), solvent-free microwave extraction (SFME), microwave assisted hydrodistillation (MAHD) and headspace solid-phase microextraction (HS-SPME) methods were subsequently investigated by means of GC and GC-MS instruments. Totally, 22, 29, 23 and 17 components were identified in the chemical profiles, representing 98.9%, 96.5%, 97.6% and 97.0% of the total compositions when using the HD, HS-SPME, SFME and MAHD methods, respectively. In all of the samples, more than fifty seven percent of the total structure consisted of monoterpene hydrocarbons. In addition, the second rank of the natural compounds was due to the oxygenated monoterpenes using the aforementioned techniques. β-Pinene was the main constituent in all chemical profiles, while the second rank was related to camphor with the exception of the volatile profile using the HS-SPME approach having more contents of α-pinene (13.4%) and limonene (9.7%) than camphor (8.2%).

Genotype-specific response of Foeniculum vulgare grain yield and essential oil composition to proline treatment under different irrigation conditions

Drought stress is a major environmental stress which severely affects growth, yield, as well as quality and quantity of crop products. Proline as a multifunction amino acid has a crucial role in ameliorating of drought stress. In order to study the effect of external proline on the response of fennel to drought stress, three fennel genotypes (namely Urmia, Shiraz, and Kerman) were exposed to two irrigation regimes (drought stress and non-stress control) and two levels of foliar-applied proline (0 and 20 mM) in a pot experiment. Drought led to significant decreases in umbels/plant, plant height, 1000-grains weight, harvest index, above-ground dry mass, grain weight and grain and dry mass WUE, root volume, root fresh and dry mass, ratio of shoot/root, grains and stems essential oil weight/plant and significant increases in root length and grains limonene content. Foliar-applied proline led to notable increases in harvest index and grain essential oil weight in the presence of drought. It also led to increases in umbels/plant, 1000-grains weight, harvest index, above-ground dry mass, grain weight and grain and dry mass WUE and ratio of shoot/root in Urmia and Shiraz genotypes. Anethole, limonene, fenchone, estragole and α-pinene were the main essential oil constituents in both grain and stems. Grain fatty acid and phytosterol compositions were not affected by experimental treatments. It may be concluded that drought stress suppresses fennel growth and grain weight, but foliar-applied proline is potent to mitigate the adverse reaction through increasing growth, grain weight/plant, WUE and grains limonene content in genotypes such as Urmia and Shiraz.

Chemical Variability of the Essential Oil of Pituranthos scoparius from Algeria.

The chemical composition of 93 oil samples from the aerial parts of Pituranthos scoparius, harvested in three regions of Algeria, was investigated by GC-FID, GC/MS and 13 C-NMR. Monoterpene hydrocarbons dominated in association with phenylpropanoids and a chemical variability was found highlighting three clusters. The composition of group I (36 samples) exhibited an atypical composition characterized by a very high contents of 6-methoxyelemicine (13.0-59.6%), followed by sabinene (1.1-43.0%) and limonene (6.6-39.0%), while the samples of group II (12 samples) contained a high content of limonene (9.2-44.0%), followed by myristicine (0.0-29.4%) and a lower amount of sabinene (0.8-2.3%). Group III (45 samples) could be divided in two subgroups. Subgroup SGIIIA was characterized by a very high content of sabinene (28.0-55.6%), followed by elemicine (0.0-29.1%), while the samples belonging to SGIIIB were characterized by the lower content of sabinene (6.2-35.5%) and a significant content of myristicine (1.5-32.4%), α-pinene (4.2-31.0%) and dill apiole (0.1-31.4%). Each harvested region was characterized by a different chemical composition.

Preparation, characterization and application of polymethacrylate-based monolithic columns for fast and efficient separation of alkanes, alcohols, alkylbenzenes and isomeric mixtures by gas chromatography

Application of monolithic columns in gas chromatography is still considered very limited. In this work, several polymethacrylate-based monolithic capillary columns were fabricated, characterized and used in gas chromatography. The five monomers used were: methyl methacrylate, (MMA), hexyl methacrylate (HMA), glycidyl methacrylate (GMA), 2-butoxyethyl methacrylate (BEMA) and isobornyl methacrylate (IBMA), while ethylene dimethacrylate was the crosslinker. The monoliths were synthesized in 30 cm length capillaries possessing inner diameters (i.d.) of 0.25 mm. The prepared monolithic columns were applied for separation of 3 series of homologous alkanes, alcohols and alkylbenzenes, as well as some isomeric mixtures. Van Deemter plots were used to optimize and compare the columns performance. The smaller methacrylates (MMA and GMA) exhibited higher porosity and permeability with low column backpressure values and poorer efficiency than the larger methacrylate monomers (HMA and BEMA). The columns prepared from IBMA monomer showed the highest pressure and the least separation efficiency. The fastest full separation of alkanes was achieved on HMA-co-EDMA column in about 3.0 min with resolution better than 2.73, while the fastest full separation of alcohols and alkylbenzenes was carried out using BEMA-co-EDMA column in less than 0.8 and 1.75 min with chromatographic resolution better than 1.27 and 1.85, respectively. Again, BEMA-co-EDMA column gave the best performance with the fastest and complete separation of all studied isomeric mixtures. For all tested series of solutes, the better separation efficiency was reached with tridecane, which gave 25,200 plates/m on the HMA-co-EDMA column. Another application was carried out using HMA-co-EDMA column for determination of myrcene and limonene, two monoterpenic isomers, in some fruit peels. Under the optimum GC conditions, a rapid separation of myrcene and limonene was achieved in less than 1.0 min with chromatographic resolution of 2.56. The highest contents of myrcene (0.131 mg/g) and limonene (1.225 mg/g) were measured in the hexane extracts of grapefruit and Egyptian orange, respectively. Finally, a comparison between the prepared columns and a commercial capillary column was performed. Based on the measured run time and HETP values, HMA-co-EDMA and BEMA-co-EDMA monolithic columns exhibited faster separation and higher efficiency for n-alkanes and alkylbenzenes than the TR-5 open tubular column, although they are 100 times shorter.

English

The effect of the time of collection on the quality and quantity of the oil obtained from Severinia buxifolia leaves as well as its antimicrobial activity was studied. The chemical composition of the hydro-distilled oils of the leaves of S. buxifolia (Poir.)Tenore, collected at the four seasons was determined by GC/MS analysis. Moreover, antimicrobial activity was studied, for the oil sample regarding the yield and quality, against selected bacteria and yeast. The highest oil yield was obtained from the leaves collected during winter (0.5%) followed by autumn (0.308%), however, those collected in spring and summer scored almost the same yield; (0.26%) and (0.283%) respectively. Limonene was the most abundant hydrocarbon in winter (35.5%), and amounted to 29.3% in summer, whereas, spring and autumn samples constituted 21.15% and 19.17% of limonene respectively. &alpha;-Santalene, accounted to 20.87% in autumn sample followed by the winter sample (18.93%), then 13.56% in the spring sample and recorded its lowest concentration in the summer sample (8.1%). Furthermore, &gamma;-elemene was detected in a lesser extent amounting to 7.75% in the spring sample, 7.33% in autumn sample, 6.28% in the winter sample and 5.54% in the summer sample. Based on the above results, as regards to limonene content, S. buxifolia leaf oil collected in winter was chosen for further antimicrobial study. The agar disc diffusion method was adopted for screening the antibacterial activity of the selected oil sample. Results show moderate effect against Escherichia coli, and Listeria monocytogenes. Nevertheless, it showed weak activity against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilus, MRSA, and Candida albicans. The MIC of the volatile oil against L. monocytogenes was 4 and 1 &micro;l/ ml against S. aureus, P. aeruginosa, B. subtilus, MRSA and C. albicans. Key words: Severinia buxifolia (Poir.) Tenore, Rutaceae, GC/MS analysis, limonene, in vitro antimicrobial activity. &nbsp

THE EFFECT OF THE USE OF GROWTH REGULATORS ON THE COMPONENT COMPOSITION OF ESSENTIAL OIL OF THE TOPS AND SEEDS OF ANETHUM GRAVEOLENS L.

The content and component composition of essential oil of air-dried phytomass and seeds of Anethum graveolens L. were determined. Dill was grown using the organo-mineral preparation Ideal and steroid phytohormone (24-epibrassinolide) Epin-extra. The use of growth regulators increased the yield of green dill (Ideal by 16%, Epin-extra by 6% compared to the control); did not affect the content of essential oil in the herbs of dill and increased the content of essential oil of dill seeds. GC/MS (Gas Chromatography / Mass Spectrometry) analysis revealed differences the ratio of the main components of the essential oil of dill when the use of growth regulators. In the essential oil of air-dried phytomass of plants, compared with the control, the content of alpha-fellandrene (1,3–1,7 times) and limonene (1,1–1,2 times) increased, anethofuran (1,4–1,8 times) and carvone (in 1,4–1,5 times). In the essential oil of dill seeds - increased content of limonene (1,7–1,9 times) and decreased carvone (1,1 times). When using growth regulators, a change in the aroma of plants was observed. The use of the Epin-extra drug caused more significant changes in the content of the major components of the essential oil of dill.

Characteristics of limonene formation during microwave pyrolysis of scrap tires and quantitative analysis

Using the test system for the microwave pyrolysis of scrap tires, the effects of different factors on the production characteristics of limonene in oils were investigated. The results showed that the optimum processing parameters for the production of limonene were the specific microwave power of 15 W/g, the weight hourly space velocity of 3.75 h−1, the tire particle size of 0.6 mm, and the absence of steel wires. The yield of limonene in the pyrolysis oil under this set of conditions was up to 23.4%. According to the pyrolysis process and the product composition, the mechanism of limonene production under microwave pyrolysis conditions was predicted. The content of limonene in the pyrolysis oil was quantitatively analyzed by an external standard method (ESM) and the peak area normalization method (PANM) separately. The numerical values of the test results obtained by multiplying PANM by the calibration factor of 1.5 equal the corresponding results obtained using the ESM method. Compared with conventional pyrolysis, the microwave pyrolysis of waste tires has a higher yield of limonene under optimized conditions. The results provide an important reference for the high-value utilization of waste tires and the utilization of resources, especially the subsequent production of limonene.

Antimicrobial and antioxidant activity of Juniper galbuli essential oil constituents eluted at different times

Junipers (Juniperus spp.) are some of the most widespread species in the world with a wide ecological adaptation. Juniper galbuli (cones or berries) and their extracts have extensive applications in pharmaceuticals, perfumery, aromatherapy, alcoholic beverages, and cooking. The objective of this study was to evaluate EO composition, antimicrobial and antioxidant activity of EO fractions captured at different timeframes during the hydrodistillation of Juniperus communis and J. excelsa galbuli. The EO fractions were captured at eight sequential timeframes after the beginning of the hydrodistillation: (0–3, 3–5, 5–10, 10–20, 20–40, 40–80, 80–160, and 160–240min). The results showed that essential oil fractions from 80 to 160 and 160 to 240min had 2–5 times greater antioxidant capacity than fractions captured at the beginning of the distillation or from the whole oil. The strongest antimicrobial activity of J. communis EO against Salmonella enterica subsp. enterica was observed in the EO obtained at the 0–3min distillation timeframe (DT, in minutes). The EO of J. communis obtained at the 0 to 3, 3 to 5, and 80 to 160min DTs showed greater antimicrobial activity against Klebsiella pneumonia, compared with the EO obtained from the 160 to 240 DT. The strongest activity of J. communis EO against Staphylococcus aureus subsp. aureus and Candida glabrata was observed with EO from the 160 to 240 DT. J. excelsa EO from the 0 to 3 and 5 to 10min DTs had greater activity against S. enterica and K. pneumonia compared with the EO from the 160 to 240 DT. Conversely, the J. excelsa EO from the 160 to 240min DT had greater activity against Clostridium perfringens and Candida glabrata. This research revealed that EO with different profiles could be obtained from the same batch of galbuli, suggesting the possibility of generating natural unadulterated oils with specific targeted profiles. Essential oils with a high content of α-pinene, β-pinene, β-myrcene, sabinene, or limonene was obtained from J. communis galbuli hydrodistilled for 3min. Essential oil with a high content of α-pinene, β-pinene, β-myrcene, or γ-terpinene was obtained from J. excelsa galbuli when hydrodistilled for 3min. The galbuli of J. communis and J. excelsa can yield essential oil fractions with novel chemical composition and bioactivity.

Structural re-arrangement of depolymerized sodium alginate enriches peltate glandular trichomes and essential oil production of spearmint

Over the past decade, radiation-degraded polysaccharides have been used as regulators of growth and development in several crop plants. In quest of the possible reasons of previously established growth-promotion activity of irradiated sodium alginate (ISA), structural parameters of irradiated and un-irradiated sodium alginate were analysed using Ultraviolet-visible spectroscopy (UV–vis) and Fourier Transform Infrared spectroscopic (FT–IR) studies to develop an understanding of structure-property relationship. Using foliar application, response to graded concentrations of ISA was tested in terms of yield and quality attributes of spearmint (Mentha spicata L.). Among different concentrations of ISA [0 (control), 40, 80, 120 and 160mgL−1], 80mgL−1 proved to be the optimum foliar-spray treatment for most of the parameters studied including peltate glandular-trichomes density, which was increased from 20 to 44mm−2. Measurements made at 150days after planting revealed that foliar application of ISA at 80mgL−1 increased the content and yield of spearmint essential oil (EO) by 36.0 and 122.6%, respectively, in comparison to the control. Compared to the control, gas chromatography mass spectrometry (GC–MS) analysis revealed an increase of 18.7% in the carvone content and a decrease of 15.7% in limonene content of the spearmint EO.

Influence of Distillation Time on the Content and Constituent of Essential Oils Isolated from Lemon verbena (Lippia citriodora Kunth)

Understanding the influence of distillation time on quality and quantity of essential oils in Lemon verbena (Lippia citriodora Kunth) may help methods of this economically important essential oil to improve the production and engineer the constituent of the oils as well as decrease the energy needed for distillation. In this study the effect of distillation time on the content and constituents of the essential oil isolated from Lemon verbena by hydro-distillation method was investigated. Four distillation times such as 1, 1.5, 2 and 3 hours were investigated. The maximum essential oil content (0.73%) was achieved after 2 hours of distillation, however, the minimum essential oil content (0.57%) was observed after 1 hour of distillation. The chemical composition of the isolated essential oil was determined by gas chromatography-mass spectrometry (GC-MS). According to the results of GC-MS analysis, 21 major compounds were detected in essential oil. Geranial (29.65%), neral (23.16%) and limonene (15.38%) were the major constituents of analyzed essential oil. The study also revealed that the highest contents of geranial, limonene and neral were obtained at 1 hour distillation time.

Improvement of Aroma and Shelf-Life of Non-alcoholic Beverages Through Cyclodextrins-Limonene Inclusion Complexes

Limonene is a monoterpene flavor compound found in several beverages. However, it easily degrades by oxidation reactions at acidic environment contributing to an undesirable off-flavor. Encapsulation technologies can protect compounds from degradation. This work focuses on the effect of using complexes of limonene with α-, β-, and γ- and HP-β-cyclodextrins in non-alcoholic beverages to improve flavor and shelf-life stability due to the chemical structure of cyclodextrins. Spray-drying technology was applied to prepare different cyclodextrin/limonene forms, from which the most promising was selected and further applied in simulated lemon juice beverages. Different drying process conditions were tested, namely feed temperature (120, 160, and 180 °C) and setting of prior incubation (temperature, room and 50 °C; time, 0.17 and 24 h). An inlet temperature of 160 °C favored the encapsulation of limonene into resulting nano/microparticles. Moreover, incubation for 24 h enhanced limonene retention for all complexes, especially for β-cyclodextrin/limonene complexes, which achieved 66% of encapsulation efficiency and a 6.25 w/w of limonene load. The β-cyclodextrin/limonene particles which enabled higher load (160 °C, 24 h) presented particle size ranging between 1 and 3 μm and were chosen to undergo an accelerated aging process in a lemon juice beverage model. This study revealed that the limonene content decreased over time for model and supplemented juice, but decreased less when β-cyclodextrin/limonene particles were added. After 10 days, which mimics 9 months of storage, 40% of complexed limonene remained in the model beverage.

Limonene encapsulation in freeze dried gellan systems.

The encapsulation of limonene in freeze-dried gellan systems was investigated. Surface and encapsulated limonene content was determined by measurement of the absorbance at 252nm. Gellan matrices were both gels and solutions. For a standard gellan concentration (0.5wt%) gelation was induced by potassium or calcium chloride. Furthermore, gellan solutions of varying concentrations (0.25-1wt%) were also studied. Limonene was added at two different concentrations (1 and 2mL/100g sample). Gellan gels encapsulated greater amounts of limonene than solutions. Among all gellan gels, the KCl gels had the greater encapsulated limonene content. However, when the concentration of limonene was doubled in these KCl gels, the encapsulated limonene decreased. The surface limonene content was significant, especially for gellan solutions. The experimental conditions and not the mechanical properties of the matrices were the dominant factor in the interpretation of the observed results.

Composition, Antifungal and Antifumonisin Activity of Pinus wallichiana, Pinus monticola and Pinus strobus Essential Oils from Patagonia Argentina

The essential oils composition of Pinus wallichiana, P. monticola and P. strobus was determined by GC-FID and GC-MS analysis. P. wallichiana was the species with the highest essential oils production with an average yield of 0.97 %, followed by P. monticola and P. strobus with 0.58 and 0.50 % (v/dry wt). The main compounds with concentration higher than 5.0 % were the monoterpene hydrocarbons: α-pinene (14.8–21 %), β-pinene (22.8–34 %), limonene (4.6–17.8 %) and myrcene (1.6–12.3 %). The essential oils from P. wallichiana and P. monticola in comparison to P. strobus have been characterized by a higher content of limonene (17.8, 14.0 and 4.6 %, respectively). On the other hand, the essential oil of P. strobus showed high levels of myrcene and oxygenated and hydrocarbons sesquiterpenes. All of the evaluated essential oils showed some inhibitory effects on the growth of F. verticillioides. However, none of the evaluated EOs significantly altered the FB1 production under the experimental conditions.Pinus wallichiana, Pinus monticola, Pinus strobus, essential oils composition, antifungal, fumonisin.

Influence of surfactant type and thermal cycling on formation and stability of flavor oil emulsions fabricated by spontaneous emulsification

Food-grade emulsions can be fabricated using simple and inexpensive low-energy homogenization methods. In this study, we examined the influence of surfactant type (Tween 40, 60, and 80), oil phase composition (limonene-to-medium chain triglyceride ratio), and temperature (25 to 95°C) on the formation and stability of flavor oil-in-water emulsions (10wt% oil, 15wt% surfactant, pH3) fabricated using spontaneous emulsification. Transparent emulsion-based delivery systems containing ultrafine droplets (d<40nm) could be formed at room temperature at certain limonene contents for all three surfactants. When these emulsions were heated and then cooled, appreciable droplet growth occurred at lower limonene levels (<60% limonene) leading to cloudiness, but ultrafine droplets were still present at higher limonene concentrations (80% limonene) leading to optical clarity. These results were attributed to the influence of oil phase composition and surfactant type on the phase inversion behavior of the surfactant-oil-water systems.