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Essential oil composition and antibacterial activity of the grapefruit (Citrus Paradisi. L) peel essential oils obtained by solvent-free microwave extraction: Comparison with hydrodistillation

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Abstract

The chemical composition of the essential oil (EO) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from the peel of grapefruit (Citrus Paradisi. L) was analysed by gas chromatography/mass spectrometry (GC/MS). Totally, twenty-five components were identified in the EO. Limonene was observed as dominant (91.5–88.6%) for two extraction methods, SFME and HD, respectively. β-Pinene (0.8–1.2%), linalool (1.1–0.7%), α-terpinene (0.7–1.0%) and the other minor components were also detected. Disc diffusion method was applied to determine the antibacterial properties of the EO. The results showed that the EO of grapefruit peel had a wide spectrum of antimicrobial activities against Staphylococcus aureus, Enterococcus faecalis, Staphylococcus epidermidis, Escherichia coli, Salmonella typhimurium, Serratia marcescens and Proteus vulgaris, with their inhibition zones ranging from 11 to 53 mm.

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... Like most citrus EO, terpenes and terpene oxides, are the main components of the CPEO [16]. CPEO has been reported to have versatile biological properties, such as antimicrobial activity [17][18][19] and antioxidant potential [20,21]. ...
... Uysal et al. [18] showed that the CPEO inhibited the growth of bacteria tested (S. aureus, S. epidermidis, E. coli, P. aeruginosa, Enterococcus faecalis, Salmonella typhimurium, Serratia marcescencs, Proteus vulgaris), except for P. aeruginosa, and the highest activity was observed against S. aureus [18]. The antibacterial properties of plant essential oils could be greatly attributed to their respective compositions [55]. ...
... Uysal et al. [18] showed that the CPEO inhibited the growth of bacteria tested (S. aureus, S. epidermidis, E. coli, P. aeruginosa, Enterococcus faecalis, Salmonella typhimurium, Serratia marcescencs, Proteus vulgaris), except for P. aeruginosa, and the highest activity was observed against S. aureus [18]. The antibacterial properties of plant essential oils could be greatly attributed to their respective compositions [55]. ...
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There is an increasing demand for bioactive-loaded bio-based packaging materials to obtain food products with extended shelf-life and improved quality. The aims of the present study were to fabricate a Citrus paradise essential oil (CPEO)-loaded Lallemantia iberica seed mucilage (LISM) based edible coating and to evaluate the effects of the CPEO-LISM edible coating on the preservation of lamb slices during cold storage for 9 days. CPEO was rich in limonene (79.4%) with superb antioxidant and antimicrobial properties. Its incorporation into the edible coating (at 0, 0.5, 1, 1.5, and 2% v/v) effectively inhibited the microbial growth (total viable count, psychrotrophic count, Escherichia coli, Staphylococcus aureus, and fungi) and lipid oxidation (peroxide and thiobarbituric values) in lamb slices. The meat color (L*, a*, b*) and sensory properties were also preserved by the edible coating containing CPEO, and the bioactive edible coating based on LISM and CPEO, particularly LISM + 2%CPEO significantly inhibited quality deterioration of lamb slices and improved the shelf-life of the meat (> 9 days). The results suggested that the LISM-CPEO edible coating could be developed as an antioxidant and antimicrobial packaging to improve the shelf-life of various meat products.
... The essential oils from C. paradise have been extensively studied (Njoroge et al. 2005;Tao et al. 2009;Flamini and Cioni 2010;Uysal et al. 2011). In the present study, the crude oil (GO1) was extracted from Citrus paradisi Macf., it was refined by vacuum distillation into GO2, and 28 and 20 compounds were identified, respectively. ...
... The results of the present study differed from the findings of previous studies (Pino and Sánchez 2000;Deng et al. 2020). Uysal et al. (2011) extracted 25 compounds from the essential oil of grapefruit peel, and Njoroge et al. (2005) isolated 67 compounds. The variation in the compounds of essential oils within the same species may be attributed to differences in weather, locations, time of harvesting, and methods of isolation (Suthisut et al. 2011;Rizvi et al. 2018). ...
... tc sensilla tricodea curvata, t sensilla tricodea, b sensilla basiconica Hu et al. 2017;Lou et al. 2017), and they have attracted much attention in recent years. Grapefruit essential oils in particular have shown antimicrobial activity against St ap hy loc oc cu s a ure us , E n t er oc oc cu s f a ec ali s, Staphylococcus epidermidis, Escherichia coli, Salmonella typhimurium, Serratia marcescens, Proteus vulgaris, and Listeria monocytogenes (Uysal et al. 2011;Kahraman et al. 2016) and repellent efficacy against the rice weevil (Yoon et al. 2007), and they inhibited the development of Aedes aegypti (Ivoke et al. 2013). The present study revealed that grapefruit essential oils showed strong fumigant activity against fire ant workers, and the most potent chemical constituent was octanal. ...
Article
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The red imported fire ant is one of the world’s most devastating invasive species, adversely affecting humans, wildlife, crops, and livestock. To control infestations, chemical pesticides are deployed extensively around the world. However, their extensive use has led to negative effects on the environment and human health. Essential oils, which are safe and ecofriendly, can potentially be used as alternatives to chemical pesticides. In this study, grapefruit essential oils were used as fumigant agents to control red imported fire ants. The crude grapefruit oil (GO1) contained 28 compounds, and the concentrated grapefruit oil (GO2), which was refined from GO1 by vacuum distillation, contained 20 compounds. D-Limonene was the dominant constituent in both GO1 (70.1%) and GO2 (73.96%), and other important constituents included β-pinene, α-pinene, β-phellandrene, octanal, d-carvone, α-terpineol, and linalool. Both the essential oils and their individual constituents (α-pinene, α-terpineol, β-phellandrene, octanal, and d-carvone) showed strong lethal fumigant effects against workers. Workers were more susceptible to GO2 than GO1, and octanal was more toxic to workers as compared with the other four constituents. When antennas of workers were treated with the two oils or the five constituents, their walking and gripping abilities were significantly suppressed, and there was an obvious bending or breaking phenomenon on the sensilla of the antennas. Fumigant activity by grapefruit essential oils and their main compounds were associated with their effects on the walking and gripping behavior of workers, and this confirmed that grapefruit essential oil is a promising, ecofriendly, and safe fumigant for the control of red imported fire ants.
... These differences could be attributed to the different cultivars or growing conditions of the fruit analyzed in these studies. Moreover, a close resemblance was noted in the limonene content of grapefruit peel EO, which was present at a concentration of 93.3% [23], 91.5% [38] and 91.8% [39]. Other monoterpene compounds such as β-myrcene, α-pinene, sabinene, linalool and thujene were also reported [23,38,39]. ...
... Moreover, a close resemblance was noted in the limonene content of grapefruit peel EO, which was present at a concentration of 93.3% [23], 91.5% [38] and 91.8% [39]. Other monoterpene compounds such as β-myrcene, α-pinene, sabinene, linalool and thujene were also reported [23,38,39]. In pummelo peel EO, limonene contributed up to 55.7% of the total EO composition, followed by β-pinene (14.7%), linalool (6.2%), β-citral (4.1%), germacrene-D (2.7%), α-pinene (2.3%), α-terpineol (2.0%), geraniol (1.6%), sabinene (1.3%) [39]. ...
... Tao et al. [40] reported similar compounds but at a much lower concentration, ranging from 0.08% to 0.63%. The difference in the extraction method, such as using a rotary evaporator at 40 • C [38], could have contributed to the significant loss of highly volatile compounds from the EO. Furthermore, Hosni et al. [41] and Hou et al. [42] found limonene to be the main component in mandarin peel EO, but other secondary compounds such as lauric acid, 1-methyl-1,4-cyclohexadiene, methyl linoleate, myristic acid, palmitic acid and β-myrcene were reported only by Hou et al. [42]. ...
Article
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A novel alternative to synthetic preservatives is the use of natural products such as essential oil (EO) as a natural food-grade preservative. EOs are Generally Recognized as Safe (GRAS), so they could be considered an alternative way to increase the shelf-life of highly perishable food products by impeding the proliferation of food-borne pathogens. The mounting interest within the food industry and consumer preference for “natural” and “safe” products means that scientific evidence on plant-derived essential oils (EOs) needs to be examined in-depth, including the underlying mechanisms of action. Understanding the mechanism of action that individual components of EO exert on the cell is imperative to design strategies to eradicate food-borne pathogens. Results from published works showed that most EOs are more active against Gram-positive bacteria than Gram-negative bacteria due to the difference in the cell wall structure. In addition, the application of EOs at a commercial scale has been minimal, as their flavour and odour could be imparted to food. This review provides a comprehensive summary of the research carried out on EOs, emphasizing the antibacterial activity of fruit peel EOs, and the antibacterial mechanism of action of the individual components of EOs. A brief outline of recent contributions of EOs in the food matrix is highlighted. The findings from the literature have been encouraging, and further research is recommended to develop strategies for the application of EO at an industrial scale.
... The low amount of limonene, by far the most abundant terpene in the peel of both lemon [25] and grapefruit [26], points to the formation of α-terpineol and terpinen-4-ol from their precursors d-limonene and linalool in the cavitation microbubbles, in accordance with what happens in orange [27] and mandarin [28] juices (rich in citric acid) after storage. Following fast protonation likely taking place in the cavitation microbubbles ( Figure 3), both linalool and limonene are readily converted into α-terpineol and terpinen-4-ol, with linalool being even more reactive than limonene [27]. ...
... Molecules 2021, 26, 51 ...
Preprint
The HS-SPME GC-MS analysis of the volatile compounds adsorbed at the outer surface of lemon and grapefruit pectins obtained via hydrodynamic cavitation of industrial waste streams of lemon and grapefruit peels in water only suggests important new findings en route to understanding the powerful and broad biological activity of these new pectic materials. In agreement with the ultralow degree of esterification of these pectins, the high amount of highly bioactive α-terpineol and terpinen-4-ol points to limonene decomposition catalyzed by residual citric acid in the citrus waste peel residue of the juice industrial production.
... This percentage is higher than others, ranging between 0.90 and 6.20% for Pakistan and Turkey Citrus limon(L.)Osbeck, respectively [26,31].The α-pinene concentration ranged between 0.65 and 3.33% in essential oil of Citrus lemon peels from Nigeria [30] and between 0.42 and 1.26% in Florida and Iran [31,32]. These values were not in agreement with our results where α-pinene is not available in the Tunisian lemon peel essential oils. ...
... This percentage is higher than others, ranging between 0.90 and 6.20% for Pakistan and Turkey Citrus limon(L.)Osbeck, respectively [26,31].The α-pinene concentration ranged between 0.65 and 3.33% in essential oil of Citrus lemon peels from Nigeria [30] and between 0.42 and 1.26% in Florida and Iran [31,32]. These values were not in agreement with our results where α-pinene is not available in the Tunisian lemon peel essential oils. ...
Article
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The present study deals with the characterization of essential oils extracted from both fresh and sun-dried lemon (citrus limon (L.) Burm.f) peels by hydrodistillation, followed by extraction with ether or ethyl acetate, yielding four essential oil samples. The extraction yield varied between 0.1 and 1.65%. The essential oils constituents were identified using GC/MS analysis; limonene was the major compound ranging between 3.75 and 76.78%. In addition, ethyl acetate and methanol extracts were prepared from sun-dried lemon peels, and characterized by HPLC–PDA-ESI–MS. Four flavanoneO-diglycosides (neoreiocitrin, neohespiridin, melitidin and naringin), three flavone di-C-glycosides(diosmetin-6,8-di-C-glycoside, apigenin-6,8-di-C-glycoside, di-C-glycosideflavone), two flavone O-diglycosides (vicenin 2, neodiosmin), three polymethoxyflavones (tangeretin, nobiletin, 5,6,7,4′-tetramethoxyflavone), and two coumarins (scoparin, isomeranzin) were identified. Lemon peels ethyl acetate extract exhibits a powerful antioxidant activity (IC50 = 0.09 µg/ mL) compared to those of vitamin E (IC50 = 0.017 µg/ mL) and BHT (IC50 = 0.026 µg/ mL). On the other hand, essential oils from fresh and sun-dried lemon peels as well as organic extracts exhibited interesting antimicrobial activities against Bacillus cereus, B. subtilis, Staphylococcus aureus (Gram+) and Salmonella enterica, Escherichia coli, Klebsiella pneumoniae (Gram−). Lemon peels would be used in the agro-food industry as alternative to the undesirable chemical additives.
... Essential oils isolated from pomelo (Citrus grandis L.) fruits are a widely adopted agent with a wide range of applications and have been known as alternative for antimicrobial and antioxidant agents (Mokbel & Suganuma, 2006). It has been shown that bioactivities of the essential oils are dependent on their chemical compositions (Uysal et al., 2011). Therefore, chemical composition of pomelo essential oil from different countries is also a subject of extensive research. ...
... Other important constituents were βmyrcene (1.3%) and α-Pinene (0.7%). These results are similar with the other literature data for Citrus genus (Uysal et al., 2011;Chen & Viljoen, 2010). ...
Article
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Hydrodistillation was used to obtain the essential oil from pomelo (Citrus grandis L.) peels collected in Vietnam. The effects of extraction variables including size of material, temperature, extraction time, and water-to-material ratio on the yield of essential oil were investigated. In addition, to assess the quality of pomelo essential oil, the chemical composition was compared. The optimized conditions were as follows: material size of grind, temperature 120°C, water to material ratio 5 mL/g, and extraction time 105 min., respectively. The chemical composition of the pomelo oil was then determined by GC-MS, where 5 components were identified, of which, limonene was the highest (97.1%). This method can be considered as a green method of extraction method as it is less energy intensive process and offers high performance. The results are expected to aid in justification of hydrodistillation in industrial applications and in refining of extraction parameters.
... Essential oils isolated from pomelo (Citrus grandis L.) fruits are a widely adopted agent with a wide range of applications and have been known as alternative for antimicrobial and antioxidant agents (Mokbel & Suganuma, 2006). It has been shown that bioactivities of the essential oils are dependent on their chemical compositions (Uysal et al., 2011). Therefore, chemical composition of pomelo essential oil from different countries is also a subject of extensive research. ...
... Other important constituents were βmyrcene (1.3%) and α-Pinene (0.7%). These results are similar with the other literature data for Citrus genus (Uysal et al., 2011;Chen & Viljoen, 2010). ...
... Grapefruit EO has been reported to have a wide range of bioactivities. It was shown to inhibit the growth of food-borne spoilage bacteria and pathogenic strains [15][16][17]. Okunowo et al. (2013) found that grapefruit EO obtained from the peel by hydrodistillation exerted inhibitory effects against bacteria and fungi, andmay be further developed for the treatment of certain diseases [18]. Grapefruit EO has shown antioxidant activity, which was important for food preservation and disease prevention [19,20]. ...
... Uysal et al. (2011) evaluated the antibacterial activities of grapefruit Eos from solvent-free microwave extraction (SFME) and hydrodistillation (HD) by the disc-diffusion method [17]. The Eos obtained from SFME and HD showed the highest activity against S. aureus with inhibition zones of 53 and 41 mm, respectively, higher than LPEO (24.34 mm). ...
Article
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Grapefruit essential oil has been proven to have wide range of bioactivities. However, bioactivity of its molecular distillate has not been well studied. In this study, a light phase oil was obtained by molecular distillation from cold-pressed grapefruit essential oil and GC-MS was used to identify its chemical composition. The antimicrobial activity of the light phase oil was tested by filter paper diffusion method, and the anticancer activity was determined by the Cell Counting Kit-8 (CCK-8) assay. Twenty-four components were detected with a total relative content of 99.74%, including 97.48% of terpenes and 1.66% of oxygenated terpenes. The light phase oil had the best antimicrobial effect on Bacillus subtilis, followed by Escherichia coli, Staphylococcus aureus and Salmonellaty phimurium. DPPH and ABTS assays demonstrated that the light phase oil had good antioxidant activity. The CCK-8 assay of cell proliferation showed that the light phase oil had a good inhibitory effect on the proliferation of HepG2 liver cancer cells and HCT116 colon cancer cells.
... The low amount of limonene, by far the most abundant terpene in the peel of both lemon [25] and grapefruit [26], points to the formation of α-terpineol and terpinen-4-ol from their precursors d-limonene and linalool in the cavitation microbubbles, in accordance with what happens in orange [27] and mandarin [28] juices (rich in citric acid) after storage. Following fast protonation likely taking place in the cavitation microbubbles ( Figure 3), both linalool and limonene are readily converted into α-terpineol and terpinen-4-ol, with linalool being even more reactive than limonene [27]. ...
... Molecules 2021, 26, 51 ...
Article
Full-text available
An HS-SPME GC-MS analysis of the volatile compounds adsorbed at the outer surface of lemon and grapefruit pectins obtained via the hydrodynamic cavitation of industrial waste streams of lemon and grapefruit peels in water suggests important new findings en route to understanding the powerful and broad biological activity of these new pectic materials. In agreement with the ultralow degree of esterification of these pectins, the high amount of highly bioactive α-terpineol and terpinen-4-ol points to limonene (and linalool) decomposition catalyzed by residual citric acid in the citrus waste peel residue of the juice industrial production.
... In another study, the extraction efficiency of pomelo peel essential oil with supercritical CO 2 extraction technique was optimized, resulting in the optimal recovery of 5.12% [5]. Uysal et al. [6] also found that the composition of essential oil extracted from pomelo peel (Citrus paradisi L.) varied depending on the extraction method with limonene ranging from 88.5 to 91.5%, linalool (0.7-1.1%), pinene (0.8-1.2%), and a-terpinene (0.7-1.0%) [6]. ...
... In another study, the extraction efficiency of pomelo peel essential oil with supercritical CO 2 extraction technique was optimized, resulting in the optimal recovery of 5.12% [5]. Uysal et al. [6] also found that the composition of essential oil extracted from pomelo peel (Citrus paradisi L.) varied depending on the extraction method with limonene ranging from 88.5 to 91.5%, linalool (0.7-1.1%), pinene (0.8-1.2%), and a-terpinene (0.7-1.0%) [6]. ...
Article
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Kinetic modeling plays a key role in development of large-scale extraction processes. In this study, we modeled the process of extracting essential oils from pomelo (Citrus maxima) peel materials in different kinetics including pseudo first order and pseudo second order kinetic models in both linear and nonlinear forms. The coefficient of determination, R², and the percentage of deviation, %q, were used as the basis to determine the most suitable kinetic model kinetics. The results show that non-linear pseudo first order model (equation 7) was best fitted to describe the experimental data. The obtained essential oil was characterized by the abundance of limonene.
... Phytochemical analysis result of C. paradisi peel EO from Turkey demonstrated presence of 25 constituent compounds of which limonene occupied the highest percentage (88.6%) of the oil. The other major compounds were α-terpinene (1%), and β-pinene (1.2%) [58]. ...
Chapter
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Citrus essential oils (CEOs) and their constituent compounds are being reported to have multifarious activities. In this chapter an attempt is made to discuss the insecticidal activities, as well as CEO profile of different vegetative part of Citrus species and biocidal potentiality of their constituent compounds against diverse insect pests. It is observed that in most of the CEO constituent profile, limonene is the major constituent compound. Other important constituents present in different percentages in different CEOs are β-citronellal, linalool, pinene, β-caryophyllene, β-myrcene, terpinene, citral etc. These plant EO constituents are reported to have insecticidal effects against diverse insect species. Taking the four peel EOs of Citrus limon, Citrus paradisi, Citrus medica, Citrus maxima commonly grown in North Eastern part of India, study on their insecticidal effects against Dolichoderus affinis (Hymenoptera: Formicidae) was made and result is presented showing higher fumigant toxicity of C. medica and C. limon oil against the ant sp. With the increasing awareness for using safe insecticidal products among consumers, the citrus EOs with their attracting terpene compounds having good insecticidal potency bear all attributes to be used as commercial green pesticides in coming days both in indoor and outdoor management of insect pests.
... The limonene content has been found to differ from different plant tissues, mostly found in citrus peels, followed by leaf and flower. The biological activities of EOs are highly dependent on cultivation, geographical location, vegetative phases and agricultural seasons of the plants (Uysal et al., 2011). Oranges are freshly consumed or processed to juice, jam which produce a vast number of orange peels. ...
Article
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The continuous fresh consumption or juice production of orange fruits (citrus nobilis) has discarded a vast number of orange peels, which has caused significant impacts on environmental issues. This study attempted to utilize discarded orange peels to extract essential oils (EOs) and evaluated their physiochemical properties, antibacterial, antifungal, and antioxidant activities. EOs were extracted via a distillation system using a Clevenger apparatus and gas chromatography - mass spectrometry analysis was employed to characterize their chemical components. The antibacterial and antifungal test were evaluated using a well diffusion method, and antioxidant activity was determined based on DPPH radicals scavenging effect and ferric reducing antioxidant power (FRAP). The obtained EOs with the yield of 3.29 ± 0.24% in which limonene was found to be the most abundant compound in the EOs (90.42%) followed by β-myrcene (4.7%) and α-pinene (1.22%). The result showed that Gram-positive bacterium (Bacillus cereus) was susceptible to the 50% EOs than Gram-negative bacterium (Escherichia coli) with respect to inhibitory zone diameter of 15.00 ± 0.58 mm and 11.33 ± 0.58 mm. The 50% EOs also inhibited nearly 70% of the mycelial growth of Aspergillus flavus as well as exhibiting antioxidant activity with IC50 values of 0.15 ± 0.01 mg/mL and 18.29 ± 0.13 mg/mL for DPPH and FRAP assay, respectively. The orange peel EOs could be a promising alternative to synthetic preservatives in food industry due to their antimicrobial and antifungal activity as well as their antioxidant activity.
... Various MAE techniques have been utilized as alternatives to conventional methods to isolate aroma substances from fruit peels (Table 3). In the study of Uysal et al. (2011), SFME was reported comparable to the hydro-distillation in terms of the yield and composition of the essential oil extracted from the grapefruit peel, however with a significantly faster process. The same study also found more oxygenated compounds and less monoterpene hydrocarbons in the microwave-treated extract, which possessed stronger antibacterial activity due to its abundant limonene. ...
Article
Fruit peel is an agricultural by-product and potential source to extract natural aroma compounds with low cost. In the past few decades, the extraction of plant aroma volatiles experienced a transition from traditional to modern technologies. This review summarizes the main aroma compounds in different fruit peels, evaluates modern extraction techniques applicable for these aroma compounds in terms of mechanism, procedure, merits and demerits, and practice. Additionally, the applications of fruit peel aroma extract in food, pharmaceutical and cosmetic industries are also discussed. This review provides comprehensive information for extraction and application of aroma compounds from fruit peels, which could facilitate the valorization of the agricultural by-products and reduce environmental impacts.
... In addition, this result is in agreement with previous studies that showed an essential oils extracted by HD were more toxic than essential oils extracted by MAE (Sahraoui et al., 2017). However, earlier studies demonstrated that essential oil obtained by microwave radiation has higher antimicrobial as well as antioxidant activities compared to the oil obtained by HD (Uysal et al., 2011). ...
Article
The main objective of the present study is to introduce a new and ecologically safe method for managing the rice weevil, Sitophilus oryzae. Therefore, Eucalyptus salubris leaves essential oils yield, chemical composition and its insecticidal activity against the adults of S. oryzae were evaluated. Moreover, a comparison of innovative and conventional extraction methods of Eucalyptus salubris essential oils collected from two arboreta in south of Tunisia (Zrig and El-Hamma) was investigate. In fact, results demonstrated that essential oils yields varied depending on the arboreta and extraction methods. Essential oils yields obtained with MAE were increased in both arboreta. Besides, results showed a significant positive association between the essential oils yields of MAE and altitude of the arboretum. These results can be used to improve the production of oils in commercial plantations. Analysis of essential oils has shown that chemical composition may differ not only in the quantity of the different compounds but also in the quality of molecules extracted, depending on the method of extraction and harvest area. Moreover, E. salubris essential oils from El-Hamma were rich in hydrocarbon monoterpenes (56%), while those from Zrig were rich in oxygenated monoterpenes (39.6%), mainly 1, 8-Cineole (30.94%). Furthermore, the fumigant toxicity varied with the harvest area, extraction process, oil concentration and exposure duration. The conventional method achieved the best performances. The Lethal Concentration (LC50) values were 25.96 μL/L air, 34.43 μL/L air and 46.74 μL/L air for E. salubris essential oils collected from El-Hamma and extracted by hydrodistillation, ultrasonic-assisted extraction and microwave-assisted extraction, respectively. Overall, extraction of essential oils out by different techniques and innovative methods avoids shortcomings of content optional techniques friendly to environmental to avoid chemical risk, extraction time and obtain yield quality of essential oils.
... To obtain essential oils, various techniques could be employed such as hydrodistillation, supercritical fluid extraction and microwave extraction [17][18][19][20]. Among which, hydrodistillation figures due to its viability, safety and suitability for herbs and plants. ...
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This study attempted the optimization of the extraction process involving essential oils from Vietnamese pomelo fruits. Three influential parameters including ratio of water and material, extraction time, and temperature were assumed to be impactful to the oil yield and were investigated by establishing a statistical model. A central composite design was adopted to generate dataset required for estimation of the model. Analysis of variance was used to calculate model significance. The results showed that optimum yield of pomelo oil is 4.46 % (v/w) corresponding to water ratio of 507 mL water to 100 g sample, temperature at 119.29 ºC and distillation time of 113.68 min. Predicted values proposed by the Design Expert 11 software well-agreed with the empirical data, suggesting the excellent predictability of the proposed models. In addition, the essential oil obtained under optimal conditions was analyzed by gas chromatography-mass spectrometry. The results indicated that D-limonene is the main component (97.318 %) of essential oil.
... Amusan et al. (2005) revealed that linalool and D-limonene are the active ingredient in the ethanolic peel extract of C. sinensis and these caused mortality of Aedes aegypti (L.) larva within 36 hr. Uysal et al. (2011) suggested that the compounds detected from leaves of C. sinensis, C. aurantium, C. limon and C. reticulata were limonene (7.18%), -pinene (4.35-30%) and linalool (0.21-63.03%). The phytochemicals predominant in Citrus plant parts were also discussed in several studies. ...
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Laboratory experiments were conducted during August to March, 2018-2019, to evaluate the insecticidal property of Citrus sinensis (L.) Osbeck fruit waste viz., peel and seed against the papaya mealybug Paracoccus marginatus (Williams and Granara de Willink). Five solvents, viz., hexane, ethyl acetate, methanol, diethyl ether and dichloromethane were used to extract the bioactive compounds. The efficacy of these extracts was evaluated against P. marginatus at 10000 ppm for their oral or contact toxicity, through leaf contamination and dry film method, respectively. The methanol extract was observed to exert maximum mortality of P. marginatus in leaf contamination method (88.89 % and 86.11 %, respectively) and also dry film method (88.33 %, 78.06 %, respectively) after 72 hr after treatment. The chemical profile of the methanol extract of seed and peel analysed with GC-MS was also done.
... The results had been showed that clear yellow essential oils with a fresh sweet odor were obtained through the steam distillation of Citrus paradisi and Citrus sinensis peels at 0.81 and 0.74% and (mL/100 g of fresh tissue), respectively. This result is line with Uysal et al (2011), who found that 0.80% of Citrus paradisi peel essential oil and Bourgou et al (2012), who found Citrus sinensis essential oil peel yield 0.74%. ...
Article
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This study examined the effect of essential oils extracted from peel of Citrus paradisi and Citrus sinensis on two species of fungi: Penicillium oxalicum and Fusarium oxysporum as well as effect of two fungicides: Carbendazim and Thiophanate-methyl against above fungi. Results showed that the essential oil of Citrus paradisi inhibited the radial growth of Penicillium oxalicum and Fusarium oxysporum at concentration 4%. Nevertheless, the essential oil of Citrus sinensis inhibited the radial growth at concentration 5 and 4%, respectively. Furthermore, the two studied fungicides inhibited radial growth of these fungi too. Therefore, there are a positive relationship between the evaluating of concentration and the percentage of inhibiting of radial growth in fungi.
... Pink grapefruit EO is characterized by a high amount of monoterpene hydrocarbons, of which limonene (above 90%), β-pinene, linalool, and α-terpinene are dominating. Moreover, pink grapefruit EO contains a lower amount of sesquiterpene hydrocarbons, aldehydes, alcohols, and esters than lemon oil [55,56]. Similarly, commercial eucalyptus essential oil is rich in limonene (about 70%), α-terpineol (about 10%), α-terpinyl acetate, and α-pinene [57]. ...
Article
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Essential oils (EOs) are complex natural products of plant origin and exhibit different desirable, e.g., antimicrobial properties. Their growth inhibition effect on the pathogenic fungi of the genus, Fusarium, which forms deoxynivalenol (DON), has been documented. DON is the most common contaminant of grains and their products, causing strong emetic effects after their consumption. The aim of the study was to investigate the ability of selected EOs to degrade DON under in vitro conditions, using various incubation terms. The impact of a different temperature, pH, incubation time, mycotoxin, and essential oil concentration was tested. The results indicate that the kind of EO influences the effectiveness of mycotoxin level reduction, and the most effective EOs were palmarosa and lemon oils. A higher reduction of DON content by EOs was achieved after 24 h of the experiment (up to 72%), at a pH range between 3 and 6 and a temperature of 20 • C. Moreover, the effect of various doses of white and pink grapefruit and palmarosa EOs (100 and 200 µL/mL) on toxin level reduction was observed. The experiment confirmed that the selected EOs may be effective in DON reduction, as previously documented in experiments with zearalenone.
... Furthermore, for this purpose, microwave systems have 24 been modified and combined with a cooling system and collector or receiving flask for collecting 25 the condensed extract. This technique has been mainly employed for extraction of essential oils 26 and the method has been sometimes characterized as solvent-free microwave hydrodiffusion and 27 gravity (Li et al., 2012b;Okoh et al., 2011;Uysal et al., 2011). Later, solvent-free microwave 28 extraction has also been employed for flavonoids extraction (Perino-Issartier et al., 2011;Vian et 29 al., 2009;Zill e et al., 2009). ...
... Mixture of essential oils (ylang ylang, lavender, pink grapefruit oils) applied on 25 March 2019 changed limonene percentage share in sample chemical composition significantly. Ylang ylang and lavender oils contain trace amounts of limonene (Stashenko et al. 1996; Baratta et al. 1998;Hui et al. 2010); however, this terpene is a main component of pink grapefruit oil (88-91%) (Njoroge et al. 2005;Uysal et al. 2011); therefore, limonene was an abundant component of air sample collected that day. Huang et al. (2012) and Hsu et al. (2012) in their studies determined that aromatherapy treatment causes submicron (< 100 nm) SOA particles growth at a level from 10,000 to 100,000 particles/cm 3 , indicating that high terpene concentration in such environments, even at low-level ozone concentration, produces large amounts of nanosized SOA. ...
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Due to excessive application of essential oils and scented products in spa salons during aromatherapy and massage sessions, the elevated concentration of total volatile organic compounds (TVOCs), particularly terpenes, which are known as secondary organic aerosol (SOA) precursors, is expected there. This study was aimed at determination of VOCs with a particular regard to terpenes in air samples collected in selected spa salons located in Northern Poland. Active air sampling was conducted before and after treatments. Samples were analyzed with the use of thermal desorption gas chromatography coupled with flame-ionization detector (TD-GC-FID) and mass spectrometer (TD-GC-MS). Obtained results allowed to characterize chemical composition of indoor air of spa salons and also to relate the dependence between applied essential oil and indoor air chemical composition. It has been proved that (i) spa salons are characterized by TVOC concentrations exceeding recommended values of 300–400 μg m−3 in most of examined cases, reaching up to several thousand of micrograms per cubic meter, (ii) TVOC concentration is strictly related to salon characteristics and carried out treatments, (iii) terpenes constitute a significant part of TVOCs present in spa indoor air, from 22 up to 86%, (iv) most commonly investigated terpenes in the literature (d-limonene, α-pinene, camphene, and linalool) were also determined at the highest concentration levels in this study and (v) VOC chemical composition is strictly dependent on the type of applied essential oils. On the basis of obtained results, it may be stated that extensive application of essential oils rich in terpenes can significantly alter indoor air chemistry of spa salons, thereby influencing health and well-being of employees working there. Graphical abstract
... Essential oils derived from citrus peels can be used in various fields, including the cosmetic, perfume, food, and pharmaceutical industries (Uysal et al. 2011;Allaf et al. 2013;Acar et al. 2015). Because of its use of simple facilities, hydro-distillation is extensively utilized in the industry for the extraction of essential oil; however, it is not easy to obtain a high yield of essential oil based on this traditional method. ...
Article
This paper describes the high-value utilization of citrus peel waste, in which potassium carbonate (K2CO3) was used to assist the extraction of essential oils and served as the activating agent for the further preparation of activated carbons. A common alkali metal salt, K2CO3, was confirmed to be effective in promoting the extraction of essential oils from citrus peel. Compared to the 2.4 wt% extraction rate of essential oils obtained using regular steam distillation, a 6.2 wt% extraction rate was achieved when the citrus peel was pretreated with a K2CO3 solution. Meanwhile, its chemical composition remained stable, indicating that these additional essential oils can also be directly used in areas that have already been developed in the perfume industry. The solid residue collected after essential oil extraction was further used as the precursor for activated carbons. The specific surface area of activated carbons reached up to 1846 m2/g at a carbonization temperature of 800 ºC, and it exhibited a highly developed microporous structure.
... One factor that influences the main compound in essential oils was discovered by Uysal's team when lower amounts of hydrocarbons monoterpene and higher amounts of oxidizing compounds in pomelo essential oils extracted by HD compared to MAHD. The oxygen compounds in essential oil samples from HD (2.8%) were lower than MAHD (4.7%) [33]. The main ingredient of the pomelo essential oils is Limonene, which contains antifungal and antibacterial properties of essential oils. ...
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Hydrodistillation (HD) is a traditional technique used in most extraction processes. On the other hand, microwave-assisted hydrogen distillation (MAHD), an advanced method using microwaves in the extraction process, has recently emerged. The chemical ingredients of essential oils obtained from pomelo (Citrus grandis L.) peels obtained by MAHD and by hydrodistillation (HD) were analyzed and compared gas chromatography-mass spectrometry (GC/MS). The results show that there is no significant difference between the two methods in terms of extraction efficiency, at around 4.45 to 4.7%. The main components of essential oils were Limonene, α-pinene, β-Myrcene and Sabinene. The content of those compounds showed no clear quantitative and qualitative difference between HD and MAHD. Experimental results show that the MAHD method provides a good alternative to extracting essential oils from grapefruit, saving time, operating costs and achieving more optimal levels. Keywords: Comparison, Pomelo (Citrus grandis L.), Essential oil, Hydrodistillation, Microwave assist hydrodistillation
... The remaining ingredients are present in small quantities: myrcene (6.9%) and alpha-pinene (1.7%), belonging to monoterpenes; and beta-caryophyllene (1.1%), belonging to sesquiterpenes [40, 59,73]. C. paradisi EO inhibited the growth of E. coli, S. aureus, E. faecalis, S. Typhimurium, Lactococcus lactis, Leuconostoc mesenteroides, Lactobacillus plantarum, Staphylococcus epidermidis, Serratia marcescens, and Proteus vulgaris [73][74][75]. The effectiveness of C. paradisi EO against fungi: A. niger, A. flavus, C. albicans, Penicillium chrysogenum, Fusarium moniliforme and Saccharomyces cerevisiae has been confirmed [76]. ...
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The role of purified natural products in the prevention and treatment of countless diseases of bacterial, fungal, and viral origin cannot be overestimated. New antiviral drugs have been obtained from natural sources and transformed into preparations for prophylactic and therapeutic purposes. Flavonoids, polyphenols, saponins, proanthocyanins, polysaccharides, organic acids, proteins, polypeptides, and essential oils derived from plants, animals, or microorganisms can control and combat foodborne viral infections, including hepatitis A. The components of essential oils are characterized by numerous therapeutic and antioxidant properties and exhibit a broad spectrum of antimicrobial and antiviral activity. Due to these properties, they can be used to preserve meat, fruit, vegetables, and their products. Over the past two decades, much effort has been made to identify natural products, mostly of plant origin, to combat foodborne viruses. Natural plant extracts have several potential uses, not limited to increasing the safety of food products and improving their quality, but also as natural antiviral agents.
... Grapefruit (Citrus paradisi) is a subtropical tree that belongs to the Rutaceae family (Sozmen et al., 2011) and is known for its mild sour to semi sweet fruits. Grape is one of the Citrus fruits cultivated and consumed in Nigeria (Odubanyo and Sangodoyin, 2002). ...
Article
In this study, effects of grapefruit peel powder (GFPP) inclusion (2.5, 3.7 and 5 g) on the physicochemical properties, antioxidant activity and sensory acceptability of cakes monitored at 0, 7 and 14 days of storage was evaluated and compared with the control cake samples. According to results, increase proportion of GFPP inclusion to cakes increased the moisture, fat, fibre, ash and energy contents, whereas, protein and carbohydrate contents decreased as the proportion of GFPP increased when compared to control cakes. The physical and chemical parameters showed that cake texture, strength, weight, and free fatty acid (FFA) decreased as proportion of GFPP inclusion and storage days increased, while loaf volume, specific volume, and peroxide value (PV) increased with increase proportion of GFPP. Also, loaf and specific volumes were higher in GFPP cakes, whereas texture, strength, weight, FFA and PV were higher in control cakes. Increment of GFPP (3.7–5 g) resulted to about 2 – 3fold significant increase in %DPPH, ABTS, FRAP and total flavonoids (TF) values than in control cakes. Similarly, increase proportions of GFPP strongly inhibited yeast and mould growth when compared to control cakes. It was also found that 3.7 g GFPP cakes at the 7th day and 5 g GFPP cakes at the 14th day of storage had the same sensory acceptability to that of the control cakes. From the results, GFPP cakes resulted to better shelf stability than the control cakes due to antioxidants compound in GFPP which may be termed as functional ingredients.
... The composition of the condensed volatiles is reported in Table 1. The composition of grapefruit oils and volatiles can vary depending on the variety, source location, and stage of maturity (27)(28)(29)(30). The major constituent in the condensed volatiles of Frontiers in Nutrition | www.frontiersin.org ...
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Culled whole grapefruit (WG) and grapefruit juice processing residues (GP) are currently incorporated into low-cost animal feed. If individual chemical components found within these side streams could be recovered as high-value coproducts, this would improve the overall value of the grapefruit crop. In this study, pectic hydrocolloids, sugars, volatiles, phenolics, and flavonoids were extracted from Star Ruby, Rio Red, and Ruby Red GP and WG using a continuous pilot scale steam explosion system. Up to 97% of grapefruit juice oils and peel oils could be volatilized and contained 87–94% d -limonene. The recovery of pectin, as determined by galacturonic acid content, was between 2.06 and 2.72 g 100 g ⁻¹ . Of the phenolics and flavonoids analyzed in this study, narirutin and naringin were extracted in the amounts of up to 10,000 and 67,000 μg g ⁻¹ , respectively.
... and α-terpinene (0.7%-1.0%). Grapefruit EO stimulates body cleansing and removal of excess fluids (Uysal et al., 2011). GP has been reported to possess antibacterial and antigenotoxic effects (Cristóbal-Luna et al., 2018). ...
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The goal of this work is to fabricate a new composite based on polyurethane (PU), grapefruit (GP) oil, and cobalt nitrate [Co(NO3)2] using an electrospinning technique. Morphology results revealed the reduction in the fiber diameter of the composites compared to pristine PU control. The interaction of PU with GP and Co(NO3)2 was confirmed by hydrogen bond formation evident in infrared analysis. The fabricated PU/GP composites depicted a more hydrophobic behavior, while PU/GP/Co(NO3)2 showed a hydrophilic behavior than the pristine PU. Atomic force micrographs (AFM) revealed that the developed composites showed a decrease in the surface roughness (R a) compared to PU. The addition of GP and Co(NO3)2 improved the mechanical strength of the pristine PU. The blood compatibility assays concluded not only the increase in blood clotting levels but also the less toxic nature of the fabricated composites compared to the pristine PU. Hence, the newly designed composites possessing outstanding physicochemical and biological properties may be used as a potential candidate for scaffolding in tissue engineering applications.
... From a previous report, a similar range of limonene was observed [26]. Extraction methods used can influence the number of volatile components present in the CEOs [27]. In this study, most secondary metabolites belong to the monoterpene class followed by oxygenated monoterpene. ...
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Citrus species of plants are among the most commercially cultivated crops, mainly for their fruit. Besides, the generally consumed flesh inside the fruit, the peel is quite important too. Essential oils extracted from the peel have a history of being used by humankind for centuries. These essential oils are rich in antioxidants and antimicrobial agents. Comparative investigation of volatile constituents, and antioxidant and antimicrobial activities were undertaken. The essential oils were evaluated through gas chromatography-mass spectrometry (GC-MS), and enantiomeric composition by chiral GC-MS. Similarly, the antioxidant properties were evaluated by 2,2-diphenyl-1-picrylhydrazyl scavenging assay, and antimicrobial activities were assayed using the disk diffusion method. The highest extraction yield of 1.83% was observed in Citrus sinensis Osbeck. GC-MS analysis showed limonene (63.76-89.15%), γ-terpinene (0.24-6.43%), β-pinene(0.15-6.09%), linalool (0.35-3.5%), sabinene (0.77-2.17%), myrcene (0.74-1.75%), α-terpineol (0.28-1.15%), and α-pinene (0.2-0.58%) as the major constituents of the essential oil of the Citrus species studied. For the first time, through our study, chiral terpenoids have been observed from Citrus grandis Osbeck essential oil. The order of antioxidant activity is as follows: Citrus grandis Osbeck red flesh > Citrus reticulata Blanco > Citrus sinensis Osbeck > Citrus grandis Osbeck white flesh. Except for Citrus grandis Osbeck white flesh (52.34 μL/mL), all samples demonstrated stronger antioxidant activities than those of the positive control, quercetin (5.60 μL/mL). Therefore, these essential oils can be used as a safe natural antioxidant to prevent product oxidation. Likewise, citrus peel essential oil showed antimicrobial activity against tested bacterial strains, albeit marginal.
... The extraction of essential oils is considered the main solution to utilize this by-product. There have been numerous attempts to recover essential oil from pomelo by-products by using a wide array of extraction methods including supercritical CO 2 extraction, solvent-free microwave (SFME), and hydrodistillation (HD) [5,6]. It has been noted that types of extraction methods can significantly affect the number of oxidizing compounds in the essential oil [7]. ...
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Pomelo peel-derived essential oils have been gaining popularity due to greater demand for stress relief therapy or hair care therapy. In this study, we first performed optimization of parameters in the pomelo essential oil extraction process on a pilot scale to gain better insights for application in larger scale production. Then extraction kinetics, activation energy, thermodynamics, and essential oil quality during the extraction process were investigated during the steam distillation process. Three experimental conditions including material mass, steam flow rate, and extraction time were taken into consideration in response surface methodology (RSM) optimization. The optimal conditions were found as follows: sample weight of 422 g for one distillation batch, steam flow rate of 2.16 mL/min and extraction time of 106 min with the coefficient of determination R2 of 0.9812. The nonlinear kinetics demonstrated the compatibility of the kinetic model with simultaneous washing and unhindered diffusion with a washing rate constant of 0.1515 min−1 and a diffusion rate constant of 0.0236 min−1. The activation energy of the washing and diffusion process was 167.43 kJ.mol−1 and 96.25 kJ.mol−1, respectively. The thermodynamic value obtained at the ΔG° value was −35.02 kJ.mol−1. The quality of pomelo peel essential oil obtained by steam distillation was characterized by its high limonene content (96.996%), determined by GC-MS.
... With regards to its numerous industrial applications and vital health-promoting properties, massive research attention has been focused on recovering essential oil from citrus fruit including underutilized citrus species. The various studies reported the extraction of essential oil from grape C. paradisi (Uysal et al., 2011) C. grandis (Ou et al., 2015), C. hystrix (Shaha et al., 2013), etc. The composition and content of essential oil particularly depend upon the extraction method and conditions irrespective of species. ...
Article
The nutritional and medicinal value of citrus fruits is well known mainly attributed to their desirable phytochemical profile. However, some citrus species are only utilized by the local folks and unknown to the other parts thus remaining underutilized. These species are abundant in bioactive compounds such as polyphenols, antioxidants, carotenoids, dietary fiber, vitamins and minerals. The various in vitro and in vivo studies confirm their potential as antioxidant, antibacterial, antiviral, anti-inflammatory, anti-diabetic, anti-cancer, anti-atherosclerosis and regulating of the glucose, cholesterol and triglycerides level in the body. This review explores a new approach to the underutilized citrus species with an emphasis on its bioactive and medicinal properties. Various attempts also have been made on the utilization of different parts of these citrus species in the food industry. The findings thus far indicate that the underutilized citrus species could be developed as a promising nutraceutical ingredient for the application in the food and pharmaceutical industry, but further studies on large scale or commercially processing of these species (particularly on bioactive compounds retention of different parts and determination of health potential as clinical trials) are recommended.
... L) belongs to the Citrus genus, a category of flowering plants in the family Rutaceae (Gupta et al., 2011). Grapefruit Peel is considered as a cheap by-product of the fruit which is a rich source of nutrients including vitamin C, essential oils such as terpens and aliphatic sesquiterpene and dietary fiber that showed invitro a wide spectrum of antimicrobial activities against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Salmonella typhimurium, and Etc., with 11 to 53 mm inhibition zone (Uysal et al. 2011). In the present study, the effects of the grapefruit peel extract and/or florfenicol in the treatment of the S. enteritidis infected broiler chicken in vivo trials were evaluated. ...
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Pest control should be ecologically-based, therefore use of ecologically safe approaches is the best variant. Essential oils of plants can affect the main metabolic, biochemical, physiological and behavioural functions of insects. In the experiment, we evaluated the influence of 20 essential oils on migration activity of imagoes of Tribolium confusum Jacquelin du Val, 1863 in the conditions of a laboratory experiment. Notable repellent activity against T. confusum was exhibited by essential oils of Jasminum officinale and Thuja occidentalis. Essential oils of Zingiber officinale and Cedrus atlantica had an attractant effect on imagoes of T. confusum. Essential oils of Rosmarinus officinalis, Melaleuca alternifolia, Lavandula angustifolia and Cinnamomum verum exhibited repellent properties while essential oils of Juniperus communis and Citrus sinensis had an attractant effect on the pests. Therefore, out of 20 studied essential oils, only four samples had notable biological effect on migration activity of T. confusum imagoes. These data indicate the possibility of using essential oils or their main components as ecologically safe natural repellents against pests of stored wheat and products of its processing.
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Present study involves to the pilot scale hydrodistillation process for production of essential oil of orange peels. The production of orange peels essential oil and the effect of several factors such as time, temperature and the ratio of solid/solvent on yield and quality were studied. In this work, we used fresh orange peels of C. sinensis (orange). The quantitative and qualitative analyses of the essential oils of orange peels were performed by GC/MS and sensory analysis. The maximum yield of orange peels essential oil was 1.2384 % (fresh matter) at distillation conditions (ground fresh material, the material-water ratio of 1:2, time of 105 min from the first drop, the temperature of 132 ºC). Kinetic studies of hydrodistillation process showed that the extraction of orange peels essential oil follows first order kinetic (R2 > 0.95). Limonene is the dominant component of the orange peels essential oil that was identified by chromatography-mass spectrometry (94.22 %). The results of test indicated the orange peels essential oil has good qualities which were suitable to the National Standards of Vietnam.
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Pear is a typically climacteric fruit and highly perishable with a low shelf life owing to extreme metabolic activity after harvesting. The present study aimed to reduce weight loss and improve the firmness of pear during storage. The lemon peel essential oil (LPEO) has gained considerable attention due to being the richest source of bioactive compounds behaved as a natural antioxidant agent, cost-effective, and generally recognized as safe (GRAS). Edible coatings equipped with a natural antioxidant agent and renewable biopolymers have gained more research fame owing to their involvement in the direction of biodegradability and food safety. In this work, edible skin coating materials (ESCMs) embedded by chitosan (1 %) and guar gum (2 %) were fabricated, and afterward, five concentrations of LPEO (1, 1.5, 2, 2.5, and 3.0 %) were incorporated either individually into the ESCMs. Findings revealed that LPEO-ESCMs significantly reduced the weight loss and improved the firmness of pear up to 45 days of storage at 4 ± 2 °C. Further, the LPEO–ESCMs have enhanced the antioxidant capacity, antibacterial efficiency, and malondialdehyde level of pear during storage time. It was concluded that 3 % of LPEO–ESCMs improved the overall acceptability of pear fruits. Taken together, the novel insights of guar gum and chitosan-based ESCMs entrapped with LPEO will remain a subject of research interest for researchers in the future.
Chapter
The grapefruit is one of the most produced and consumed citrus fruits in the world, with an average annual production of 7 million tonnes. It has become increasingly popular, as it is considered a low-calorie fruit, rich in vitamins, minerals and many other valuable nutrients (flavonoids, carotenoids, essential oils…). Over half a million tonnes of grapefruit undergo processing, mainly into juice, which generates large amounts of wastes (peel, seeds, pulp and leftover membrane), since only 50% of the fruit is used in this manufacturing process. Today, these wastes are mostly discarded or used as cattle feed. These practices are unfortunate, as grapefruit processing wastes could be a source of high-added economic value. Indeed, they represent a source of dietary fibers, sugars, essential oils, flavonoids and carotenoids, valuable in various industrial sectors (energetic, agricultural, pharmaceutical, cosmetic and food). Thus, if grapefruit wastes can be used to produce biogas or bio-energy, to fertilize soil or as biosorbent in wastewater treatment, the recovery of their bioactive compounds (e.g. pectin, essential oils, carotenoids and flavonoids) could be also highly pertinent, as these compounds present a wide spectrum of technological properties and/or health benefits. Extraction processes usually adopted to recover those compounds use organic solvents, high temperatures and long extraction times, which are considered to generate a high environmental impact. As a result, in recent decades, different operating strategies have been developed (ultrasound-, microwave-, pulsed electric field-assisted extraction, and supercritical fluids), with the objective of increasing extraction yields while reducing use of resources. However, most of them have still economic or technological limitations that prevent their development in small and medium-sized enterprises. The present chapter expands on the aforementioned aspects of grapefruit wastes, with the objective of demonstrating their high re-use potential. This chapter presents the potential valorization of grapefruit wastes in food and non-food applications and offers a brief overview of the main emergent extraction technologies.
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The chemical profiles of the stem, root and fruit peel essential oils of Citrus jambhiri were investigated. Pulverized plant samples (500 g) each was hydrodistilled using all-glass Clevenger-type apparatus to obtain the essential oils. Two-dimensional GC-TOFMS was used for compositional profiling of the extracted oils. Chemical profiling of the stem oil of C. jambhiri revealed the presence of 64 components (83.11 %), the root oil of C. jambhiri showed 55 components (74.21 %) and the fruit peel oil of C. jambhiri revealed 25 components (83.56 %). The major components of the stem oil of C. jambhiri is 3,4-dimethyl-1,5-cyclooctadiene(13.43 %); geijerene (14.38 %) and γ-terpinene (8.07 %) were observed as main constituents in C. jambhiri root oil whereas cis-linalool oxide (19.85 %), trans-linalool oxide (furanoid) (14.86 %), terpinen-4-ol (7.37 %) and limonene (4.64 %) were the major components of C. jambhiri fruit peel oil. Even though the samples were obtained from the same plant, the compositional profile of the essential oils from various plant parts differs.
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Measures against pests should be performed in the context of integrated management of agricultural crops and complex control of pests. Therefore, use of ecologically safe approaches is the best option. Essential oils of plants can make an impact on the main metabolic, biochemical, physiological and behavioural functions of insects. We evaluated the effect of 18 essential oils and 18 dried plants on migratory activity of Sitophilus granarius (Linnaeus, 1758) and Tenebrio molitor Linnaeus, 1758 in conditions of laboratory experiment. Notable repellent activity against S. granarius was exhibited by Citrus sinensis and Picea abies. Repellent action against T. molitor was displayed by dried and cut leaves of Origanum vulgare and Eucalyptus globulus, and also essential oils from Juniperus communis, Р. abies, Pterocarpus santalinus, C. sinensis and C. aurantiifolia. Therefore, out of 18 studied essential oils, only two samples had a notable biological effect on migratory activity of S. granarius and five samples – on T. molitor. These data indicate a possibility of using essential oils or their main components as ecologically safe natural repellents against pests of stored wheat and products of its processing.
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In the study, improvement in antibacterial properties of grapefruit peel essential oil after the nanoemulsification process was investigated. The essential oil composition was characterized using GC-MS, with d-Limonene being the main identified compound (82.86%). The antibacterial properties against common food-borne pathogens (Staphylococcus aureus, Enterococcus faecalis, Klebsiella pneumoniaand Salmonella Paratyphi A) as well as 6 fish-spoilage bacteria isolated from 4 spoiled fish species: mackerel, sardine, anchovy and rainbow trout, have been evaluated using paper disc diffusion, MIC and MBC methods. The grapefruit peel essential oil showed bacteriostatic properties against the majority of tested bacterial strains, however, only the growth of Salmonella parathypi A, Vibrio vulnificus and Seratialique faciens was inhibited by the essential oil in the concentration up to 25 mg/mL. Incorporation of essential oil into the nanoemulsion system resulted in increased bacteriostatic potency when the oil concentration in the nanoemulsion were considered, however, no bactericidal effect was observed, which was probably due to too low concentration of essential oil in the nanoemulsion system. The improvement in the nanoemulsion preparation method and formulation should be investigated to further improve its antibacterial properties.
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Currently, agriculture has shifted to green production, in which the recycling of post-production by-products is a key issue. In the present work, by-products such as pomelos were studied to promote consumption and enhance the value of pomelo. From pomelo material, essential oils extracted from pomelo peels, pectin, and drying pomelo products have been diversified. In the extraction process of essential oils, the hydrodistillation method was applied in conjunction with the response surface method to obtain the optimal conditions of influence factors. These essential oils were quantified as well as determined for components by GC-MS. The pectin recognition process was done by immersion method in HCl acid (pH 2) and the drying process was made with a heat pump dryer under the effects of drying temperature, drying time and wind rate. The results of the essential oil products reached the highest (0.88 ±0.006 g) at the material size of 3 mm, the distillation time of 27 min, and the ratio of raw materials/solvents of 1/12 g/mL. The main components found in pomelo peeling essential oils included limonene (71.768%), γ-terponene (12,847%), α-Phellandrene (2.979%), β-myrcene (2.668%), 1R-α-pinene (2,656%), and β-pinene (1,191%). The pectin content was the highest under the temperature of 90 °C, extraction time of 60 min and ratio/solvent ratio of 1:32 g/mL. Under these extraction conditions, 48% of concentrated pectin content was obtained. Surveying conditions for drying white pomelo peels are capable of reversing: refunded drying pomelos are drying heat pumps in the following conditions: 50 °C drying temperature, the drying time of 90 min, and wind rate of 12 m/s. Product with hardness 309.862 N.
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The evaluation of the technical and economic separation of the monoterpenes α‐pinene and d‐limonene from essential oils, carried out through computational simulation of the vacuum fractional distillation in continuous and batch from samples of turpentine and citrus oils, was developed using Aspen Plus® software combined with OPEX and CAPEX estimations based on the Guthrie method. The production of d‐limonene and α‐pinene with high purity from the essential oils is a technically feasible process. From the economic point of view and based on the average annual import costs of turpentine and orange oils in Colombia, it was found that α‐pinene and d‐limonene selling price, obtained from the distillation module cost analysis, depend on the daily production and can be minimized if essential oils are preliminary extracted from local industrial wastes.
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Chapter
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This book has been presented the sciences ideas of advances in biology, agriculture and chemical sciences. Contents of each topic have been mentioned with emphasizes their illustration. All authors have contributed towards the publication of this book. Sections of biology, agricultural sciences, forestry and environmental conservation, organic chemistry, analytical chemistry, environmental chemistry have been designed in order to explain the concepts of different branches of science and technology.
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Nowadays, almost 300 essential oils (EOs) are commonly traded in the world market, with a prediction to be worth over $14 billion in 2024. EOs are natural preservatives for food products in order to reduce the activity of pathogenic microorganisms, therefore their use as an antioxidant or a preservative in foods has been encouraged. They are not only considered as antimicrobial or flavoring agents, but are also incorporated into food packaging materials. There are several types of EOs which have been approved as food additives by the Food and Drug Administration. Hence, it is important to use safe EO products to minimize possible adverse effect risks such as nausea, vomiting, necrosis, nephropathy, mucous membrane, and skin irritation. This review article gives information about some EOs that are used in the food industries and the types of some allergenic compounds and biocides which could make the EOs hazardous or may cause allergenic reactions in the human body. Besides, some analysis techniques of possible allergenic compounds or biocides in EOs were introduced and supported with the most relevant studies. The overall conclusion from the study is that pregnant women, patients taking drugs (e.g., diabetics) or the having a history of allergy are the most prone to be affected from EO allergenic components. As regards to biocides, organochlorine and organophosphorus types of pesticides that are carried over from the plant may be found mostly in EOs. The most common allergic reaction is skin sensitization and irritation if the EO components are oxidized during storage or transportation. Moreover, drug interactions are one of the other possible adverse effect. Hence, determination of biocides and possible allergenic component concentrations is an essential factor when they are used as a preservative or flavoring agent. The most prominent analysis techniques are gas and liquid chromatography because most of the allergens and biocides are mainly composed of volatile components. Practical Application Determining of the essential oil's content will be crucial if oils are used for food preservation or flavoring because they may have some hazardous effects, such as nausea, vomiting, necrosis and nephropathy. Therefore, after applying them to the food products, consumers (especially pregnant women) should be informed about their concentration levels and their possible adverse effects are taken into account when they are consumed over toxic limit. For this reason, we reviewed in our study that some allergenic components, biocides and toxic limits of EOs to be used in food products. In addition to this, recent analytical techniques have been explained and discussed which methods are suitable for analysis.
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Enantiomers of limonene, which are often used in conjunction with other terpenes in medicinal products for the treatment of gallstones and ureteric stones, were assessed for their bioactivity in vitro. There was a substantial difference in the activity of the two enantiomers: the (+) enantiomer exhibited the higher activity against 19 of 25 different bacterial species and showed higher activity against 13 of the 20 different varieties of Listerin monocytogenes; the two isomers behaved differently against six of the eight species of fungi and against different pharmacological tissue preparations in vitro including rat vas deferens, phrenic nerve - diaphragm, caecum and uterus and guinea-pig ileum. The results indicate that the proportion of enantiomers could drastically affect the potency of the drugs in vivo.
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The chemical composition of Satureja montana, L. subsp. montana, and S. montana, subsp. variegata, (Host.) P.W. Ball, oils obtained from ten ecologically different locations in Croatia, Bosnia and Hercegovina were investigated by TLC and GC. The oil content varied from 0.66% to 1.47%. Substantial variations in relative concentrations of individual components were also noticed. The main component found in the oils was carvacrol (5.58–84.19%). The thymol content was quite low (0.45–2.84%) in most samples except for two, where it was significantly higher (8.01–13.61%). Cluster analysis and principal component analysis revealed the presence of four distinct chemotypes; however, the results obtained suggested that essential oil composition was not a useful chemotaxonomic character to partition between S. montana, subsp. montana subsp. variegata.
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Many terpenes used therapeutically or as flavor and fragrance materials are chiral compounds. Chiral separations have been advocated for the identification of adulteration of commercial oils as different essential oils and synthetic components contain different proportions of each enantiomer. An alternative method of assessing enantiomeric composition and thereby adulteration was tested using several biological parameters versus the bioactivity of the enantiomers of α-pinene. It was found that 18 out of 25 different bacteria were more affected by the (−) enantiomer of α-pinene; 19 out of 20 different L. monocytogenes strains were affected more by the (+) isomer and two of three filamentous fungi were affected more by the (+) enantiomer. The (−) enantiomer was more spasmogenic on smooth muscle than the (+) enantiomer. This suggests that differing bioactivities can indicate adulteration and also that medicaments containing chiral components should be formulated using the most suitable enantiomeric forms for each particular medical condition.
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The present study describes the phytochemical profile and antimicrobial activity of Satureja subspicata Vis. essential oils, collected in Dalmatia (Croatia). Three samples of essential oils were obtained from the aerial parts of the plant by hydrodistillation and analyzed by GC–MS. From the 24 compounds representing 97.47% of the oils, carvacrol (16.76%), α-pinene (13.58), p-cymene (10.76%), γ-terpinene (9.54%) and thymol methyl ether (8.83%) appear as the main components. The oils also contained smaller percentages of myrcene, linalool, β-caryophyllene, limonene, geranyl acetate, 1-Octen-3-ol, nerol, thymol and borneol. Furthermore, antimicrobial activity of the oil was evaluated using agar diffusion and broth microdilution methods. The antimicrobial test results showed that the oils had a great potential antimicrobial activity against all 13 bacteria and 9 fungal strains. Gram-positive bacteria are more sensitive to the investigated oil, with a range of 0.09 to 6.25 μl/ml than Gram-negative bacteria in the range which is significantly higher from 1.56 to 25.00 μl/ml. Results presented here may suggest that the essential oil of S. subspicata possesses antimicrobial properties, and is therefore a potential source of antimicrobial ingredients for the food and pharmaceutical industry.
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In the early nineties the presence of flavonoids in Citrus juices began to attract the attention of a number of researchers, as a result of their biological and physiological importance. This short review will explore two different aspects. The first part will focus on analytical techniques for the characterization of juices from different Citrus fruits regarding their flavonoid content (even if present in only trace amounts), concentrating on the most widely used methods (LC-MS and LC-MS-MS). The second part analyzes data reported in the literature regarding the composition of Citrus juices. The main components that have been detected so far are flavanone-O-glycosides and flavone-O- or -C-glycosides. The presence of such derivatives in various hand-squeezed and industrial juices is discussed, with special emphasis on their correlation to different species.
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The solubility in water of essential oil constituents is directly related to their ability to penetrate the cell walls of a bacterium or fungus. The antimicrobial activity of essential oils is due to their solubility in the phospholipid bilayer of cell membranes. Terpenoids which are characterized by their lability have been found to interfere with the enzymatic reactions of energy metabolism.
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The solvent-free microwave extraction (SFME) of cardamom essential oil (Elletaria cardamomum L.) was studied. A multivariate study based on a central composite design (CCD) was used to evaluate the influence of three major variables affecting the performance of the solvent-free microwave extraction of cardamom seed. The yield and the composition of the essential oils from the dry cardamom seeds obtained by SFME were determined, and compared with those obtained by the traditional hydro-distillation (HD). Statistical treatment of the results provided by the CCD revealed that the selected parameters: extraction time, irradiation power and moisture content of the seeds were significant. The essential oils were analysed by gas chromatography–mass spectrometry (GC–MS). Essential oils provided by SFME are dominated by the oxygenated fraction which is the more valuable and composed of highly odoriferous aromatic compounds. Cardamom seeds treated by SFME and HD were observed by scanning electronic microscopy (SEM). Micrographs provide more evidence of the destruction of cardamom seeds treated by SFME, in contrast to conventional hydro-distillation.
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Rind oils of nine cultivars of mandarin originated by recent mutation (Loretina, Marisol, Arrufatina, Clemenules, Clemenpons, Hernandina, Oronules, Satsuma Okitsu, Satsuma Owari) belonging to the Citrus reticulata Blanco species and 2 hybrids Fortune (Citrus tangerine Hort. ex Tan x Citrus clementina Hort ex Tan) and Nova (Tangelo Orlando x Citrus clementina Hort ex Tan) were obtained from ripe fruits of trees growing in the same environmental and cultivated conditions. The study of their chemical composition was carried out by capillary GC, GC/MS and the results were submitted to discriminant analysis. The first discriminant function separates the α-thujene chemocultivar, corresponding to oriental mandarin cultivars (Satsuma Okitsu, Satsuma Owari), from the Mediterranean cultivars. Inside this last group, the second discriminant function split up the sabinene chemocultivar (Marisol, Arrufatina Clemenpons and Loretina from the hybrids group (Fortuna and Nova) and alters (Clemenules and Hernandina)). The differential compounds of these groups are: α-thujene α-pinene, sabinene, myrcene, limonene, linalool, α-terpineol and germacrene-D.
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Orange oil obtained from fresh fruit peels by cold pressing was subjected to hydrogenation at 60, 70 and 80°C and 0.46 MPa (H2 pressure) over Adam's catalyst (PtO2 at 0.5 and 0.75%, w/w). The chemical composition of neat and hydrogenated oil was established by high-resolution gas chromatography (HRGC) with flame ionization (FID) and mass spectrometric (MS) detection. The principal components of orange oil were monoterpenes (limonene 94.00%, α-pinene 0.54%, sabinene 0.74%, ß-myrcene 1.18%), followed by oxygenated compounds such as alcohols (linalool 0.89% and α-terpineol 0.06%) and aldehydes (citral-Z 0.09%, citral-E 0.14%, citronellal 0.07%). HRGC-FID-MS analysis of the hydrogenated mixtures revealed the presence of over twenty components, mainly the products of hydrogenation of limonene, citral, linalool, ß-myrcene, sabinene and ß-ocimene. α-Pinene and aliphatic aldehydes did not react under these conditions. The appearance of α-terpinolene and the increase of γ-terpinene concentration from 0.05% to 0.15% in the modified oils indicated isomerization associated with hydrogenation. Citral (E- and Z-) was converted into citronellal (0.06–0.12%) and dihydrocitronellal (0.06–0.16%). Linalool was transformed into 3,7-dimethyl-1-octen-3-ol (0.42–0.63%) and 3,7-dimethyloctan-3-ol (0.11–0.32%). Various isomers formed by H2 addition to the endo and exo double bonds in limonene constituted the main products (up to 95%) in the hydrogenated orange oils. The concentration of hydrogenated products increased from 62.78 to 89.76% when the temperature dropped from 80 to 60°C at a catalyst concentration of 0.5% (w/w). A smaller change was observed with 0.75% (w/w) catalyst.
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The volatiles spontaneously emitted in vivo by different plant parts of grapefruit (Citrus paradisi Macf., Rutaceae) were collected by solid phase micro-extraction (SPME) during the whole vegetative cycle of the plant and characterised by GC–MS to verify their involvement in entomophilous pollination, a controversial topic in the biology of this species. Furthermore, the essential oils obtained by expression of the pericarp from unripe and ripe fruits were studied. Altogether 127 compounds were identified, accounting from 82.1% to 99.9% of the whole volatiles. The main constituents detected were mono- and sesquiterpenes, with limonene (0.5–95.2%), linalool (0.2–52.5%), sabinene (0.5–42.5%), myrcene (0.2–15.4%), and β-caryophyllene (0.3–41.0%) as the most represented ones.All the data were submitted to multivariate statistical analysis, highlighting many differences amongst the different plant parts and their developmental stages.
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This review presents the latest advances in the application of microwave energy to analytical chemistry. The fundamental principles of microwave field interaction with the matter are presented and their significance for the chemist is discussed, followed by the basic principles of microwave equipment construction and operation. Examples of the techniques that utilized microwave energy for digestion, extraction, chemical reaction, preconcentration, and desorption of the analytical sample are presented. A separate section describes the examples of usage of microwave technology in catalysis, environmental, and nuclear chemistry and engineering.
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Flavonoids are a widely distributed group of polyphenolic compounds with health-related properties, which are based in their antioxidant activity. These properties have been found to include anticancer, antiviral, antiinflammatory activities, effects on capillary fragility, and an ability to inhibit human platelet aggregation. The antioxidant capacity of any flavonoid will be determined by a combination of the O-dihydroxy structure in the B-ring, the 2,3-double bond in conjugation with a 4-oxo function and the presence of both hydroxyl groups in positions 3 and 5. Flavanones, flavones, and flavonols are the flavonoids present in Citrus, and although flavones and flavonols have been found in low concentrations in Citrus tissues, in relationship to flavanones, these types of compounds have been show to be powerful antioxidants and free radical scavengers. Some Citrus flavonoids can be used directly as repellents or toxins or be used in plant improvement programs to obtain more resistant crops. In addition, some Citrus flavonoids and their derivates, in the field of food technology, are principally known for their ability to provide a bitter or sweet taste and as bitterness inhibitor. Keywords: Free radicals, antioxidant; anticarcinogenic; antiinflammatory; platelet aggregation; antiallergic; analgesic; antimicrobial; food additives
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The physicochemical indices and the qualitative and quantitative composition of the volatile fraction and the oxygenated heterocyclic fraction of cold-pressed Key lime oil (types A and B) and Persian lime oil are reported. The volatile fraction of Persian lime oil is characterized by a higher content of limonene, γ-terpinene, esters, and monoterpene aldehydes and a lower content of β-pinene + sabinene, sesquiterpenes, and aliphatic aldehydes than Key lime oils. Oxypeucedanin was not detected in Key lime oil type A, while it is present in Key lime oil type B and Persian lime oil. This is probably due to the extraction technology used for Key lime oil type A, which allows the essential oil to come into contact with the juice. Under these conditions, the epoxy ring of oxypeucedanin is opened by hydrolysis to form oxypeucedanin hydrate. Keywords: Citrus aurantifolia Swingle; cold-pressed Key lime oil; type A; type B; Citrus latifolia Tanaka; cold-pressed Persian lime oil; volatile fraction; limonene; γ-terpinene; β-pinene + sabinene; coumarins; psoralens; oxypeucedanin
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Essential oils of Thymbra spicata, Satureja thymbra, Salvia fruticosa, Laurus nobilis, Mentha pulegium, Inula viscosa, Pimpinella anisum, Eucalyptus camaldulensis, and Origanum minitiflorum plants growing wild in southern Turkey were investigated by means of GC-FID, and 20 components were identified. The main ones were gamma-terpinene, p-cymene, thymol, and carvacrol as well as 1,8-cineole, pulegone, and anethole. Biological assays showed that fungitoxicity against the soil-borne plant disease-causing fungi Fusarium moniliforme, Rhizoctonia solani, Sclerotinia sclerotiorum, and Phytophthora capsici was due to different concentrations of the phenolic fraction (especially thymol and/or carvacrol) in the essential oils.
Article
The essential oil of seeds of cumin (Cuminum cyminum L.) from Bulgaria stored for more than 35 years was analyzed by physicochemical methods, GC, GC-MS and olfactometry and its antimicrobial activity tested using different strains of microorganisms. More than sixty constituents of this cumin oil could be identified as essential volatiles, responsible for the pleasant fresh, clean, spicy (typical cumin-like) odour of a high quality product. Cumin aldehyde (36%), β-pinene (19.3%), p-cymene (18.4%) and γ-terpinene (15.3%) were the principal compounds found. Antimicrobial testing showed high activity of the essential C. cyminum oil against the mold Aspergillus niger, the Gram (+) bacteria Bacillus subtilis and Staphylococcus epidermidis as well as the yeast Saccharomyces cerevisiae and Candida albicans.
Article
The necessity for pesticide-free fresh produce have prompted investigating the effect of selected essential oils and their major components on inhibition of conidial germination, appressoria formation and membrane permeability changes of the pathogens responsible for crown rot of banana. Eugenol, which is the major component of the essential oil of Ocimum basilicum, was the most effective chemical component in inhibiting conidial germination of Colletotrichum musae and Fusarium proliferatumin vitro while Cymbopogon citratus oil was the least effective. Both O. basilicum and C. citratus oils and their major components (Eugenol, citral a + b) inhibited appressoria formation by C. musae and changed the selective permeability of conidial membranes. Ocimum basilicum oil, eugenol and citral a + b could be satisfactorily used for inhibition of conidial germination and disruption of conidial activity of banana pathogens.
Article
Attention is drawn to the development of a new and green alternative technique for the extraction of essential oils from spices. Solvent-free microwave extraction (SFME) is a combination of dry distillation and microwave heating without added any solvent or water. SFME and hydrodistillation (HD) were compared for the extraction of essential oil from three spices: ajowan (Carum ajowan, Apiaceae), cumin (Cuminum cyminum, Umbelliferae), star anise (Illicium anisatum, Illiciaceae). Better results have been obtained with the proposed method in terms of rapidity (1 h vs. 8 h), efficiency and no solvent used. Furthermore, the SFME procedure yielded essential oils that could be analysed directly without any preliminary clean-up or solvent exchange steps. Copyright © 2004 John Wiley & Sons, Ltd.
Article
The chemical composition of the essential oil obtained from the peel of Bingtang sweet orange (Citrus sinensis Osbeck) was analysed by gas chromatography and gas chromatography/mass spectrometry (GC/MS). Twenty-seven components were identified. The monoterpenes and sesquiterpene hydrocarbons with 96.03% (w/w) of the total oil were the principal compound groups. Among which, limonene was observed dominant (77.49%), followed by myrcene (6.27%), α-farnesene (3.64%), γ-terpinene (3.34%), α-pinene (1.49%), sabinene (1.29%) and other minor components. Results by disc diffusion method and minimum inhibitory concentration (MIC) determination method showed that the essential oil had a wide spectrum of antimicrobial activities against Staphylococcus aureus, Penicillium chrysogenum, Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae, with their inhibition zones ranging from 14.57 mm to 23.37 mm and the MIC ranging from 4.66 μL mL−1 to 18.75 μL mL−1.
Article
Solvent-free microwave extraction (SFME) is a recently developed green technique which is performed in atmospheric conditions without adding any solvent or water. SFME has already been applied to extraction of essential oil from fresh plant materials or dried materials prior moistened. The essential oil is evaporated by the in situ water in the plant materials. In this paper, it was observed that an improved SFME, in which a kind of microwave absorption solid medium, such as carbonyl iron powders (CIP), was added and mixed with the sample, can be applied to extraction of essential oil from the dried plant materials without any pretreatment. Because the microwave absorption capacity of CIP is much better than that of water, the extraction time while using the improved SFME is no more than 30 min using a microwave power of 85 W. Compared to the conventional SFME, the advantages of improved SFME were to speed up the extraction rate and need no pretreatment. Improved SFME has been compared with conventional SFME, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD) for the extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim. By using GC–MS system the compositions of essential oil extracted by applying four kinds of extraction methods were identified. There was no obvious difference in the quality of essential oils obtained by the four kinds of extraction methods.
Article
The compositions of Vietnamese pummelo (Citrus grandis Osbeck), orange (C. sinensis Osbeck), tangerine (C. reticulata Blanco var. tangerine) and lime (C. limonia Osbeck) peel oil samples have been investigated by GC and GC–MS. The essential oils were extracted by the cold-pressing method. Hydrocarbons, followed by aldehydes and alcohols, were the most abundant compounds in all four kinds of samples. Their percentages, respectively, were >98.7%, >97.6%, >98.6% and >95.4% in hydrocarbons; >0.3%, 0.4%, >0.3% and 1.1% in total aldehydes; 0.2%, 0.5%, 0.4% and 0.7% in alcohols. In Vietnamese pummelo oil, γ-terpinene was not detected, while terpinolene was detected in small amounts and nootkatone only at a level of <0.05%. Orange oil composition was comparable to that of other sweet orange oils. δ-3-Carene was detected at a level of 0.1%. Tangerine oil is easily distinguished from other citrus oils by its content of various aliphatic aldehydes. Lime oil presented a very different composition from the other oils studied. Its limonene content was substantially lower than that of pummelo, orange and tangerine oils, whereas γ-terpinene, β-pinene and α-pinene occurred in higher proportions, moreover, the sesquiterpene hydrocarbon fraction of this oil is qualitatively more complex and quantitatively more abundant than in the other oils. Copyright © 2002 John Wiley & Sons, Ltd.
Article
Samples of Origanum vulgare ssp. hirtum were collected from the same geographic area in the south of Croatia at different seasons of growth. The maximum fluctuations found for the main components from fresh plant material were: thymol [149.2–1124.4 mg (100 g)–1], carvacrol [51.6–564.3 mg (100 g)–1], p-cymene [20.2–220.9 mg (100 g)–1] and γ-terpinene [50.1–217.5 mg (100 g)–1]. The oregano that was analysed belonged to a thymol/carvacrol chemotype. The season of collecting affected the qualitative and quantitative composition of the essential oil. The most impressive difference was the increase of p-cymene content in August. After the drying of the plant material, all samples showed a minor decrease in essential oil yields when compared with fresh plants. Drying, at room temperature, had no effect on the qualitative composition of oregano oil. Because of the variability of essential oil compositions from seasonally collected fresh and dried oregano, it would be important to check the quantity and quality of such components before usage.
Article
The essential oil of Tarchonanthus camphoratus (Asteraceae), obtained by hydro-distillation, was analysed by gas chromatography–mass spectrometry (GC–MS) and also evaluated for antimicrobial activity. Out of 45 peaks representing 99.8% of the oil, 38 components which constitute 95.8% of the total oil were identified. The oil was dominated by monoterpenes, which accounted for 80.9% of the oil. This study indicates the presence of a high percentage of oxygenated monoterpenes (62.3%), of which the main constituents were fenchol (15.9%), 1,8-cineole (14.3%) and α-terpineol (13.2%). Other monoterpenes present in fairly good amounts were α-pinene (6.87%), trans-pinene hydrate (6.51%), terpinen-4-ol (4.74%) and camphene (3.76%). The oil was screened for antimicrobial activity against both Gram positive (Staphylococcus aureus, Bacillus ssp.) and Gram negative (Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Klebsiella pneumoniae, Proteus mirabilis) bacteria and a pathogenic fungus Candida albicans. Except for P. aeruginosa, which showed resistance, the oil had pronounced antibacterial and antifungal activities.
Article
Rosmarinus officinalis L. is a perennial herb that belongs to the Lamiaceae family. It is used as a food flavouring agent, and well known medicinally for its powerful antimutagenic, antibacterial and chemopreventive properties. Essential oils were obtained from this plant by hydrodistillation (HD) and solvent free microwave extraction (SFME). GC–MS analyses of the oils revealed the presence of 24 and 21 compounds in the essential oils obtained through HD and SFME, respectively. The total yield of the volatile fractions obtained through HD and SFME was 0.31% and 0.39%, respectively. Higher amounts of oxygenated monoterpenes such as borneol, camphor, terpene-4-ol, linalool, α-terpeneol (28.6%) were present in the oil of SFME in comparison with HD (26.98%). However, HD oil contained more monoterpene hydrocarbons such as α-pinene, camphene, β-pinene, myrcene, α-phellanderene, 1,8-cineole, trans β-ocimene, γ-terpenene, and cis sabinene hydrate (32.95%) than SFME extracted oil (25.77%). The essential oils obtained using the two methods of extraction were active against all the bacteria tested at a concentration of 10 mg ml−1. Minimum inhibitory concentration (MIC) values for all the susceptible bacteria ranged between 0.23 mg ml−1 and 7.5 mg ml−1.
Article
The objective of this work was to study the effect of the essential oils of lemon (Citrus lemon L.), mandarin (Citrus reticulata L.), grapefruit (Citrus paradisi L.) and orange (Citrus sinensis L.) on the growth of moulds commonly associated with food spoilage: Aspergillus niger, Aspergillus flavus, Penicillium chrysogenum and Penicillium verrucosum, using the agar dilution method. All the oils showed antifungal activity against all the moulds. Orange essential oil was the most effective against A. niger, mandarin essential oil was most effective at reducing the growth of Aspergillus flavus while grapefruit was the best inhibitor of the moulds P. chrysogenum and P. verrucosum. Citrus essential oils could be considered suitable alternatives to chemical additives for use in the food industry.
Article
This study was designed to examine the in vitro antimicrobial and antioxidant activity of the essential oil and various extracts prepared by using solvents of varying polarity from Cyclotrichium origanifolium (Labill.) Manden. & Scheng. The essential oil was particularly found to possess stronger antimicrobial activity while other non-polar extracts and subfractions showed moderate activity and polar extracts remained almost inactive. GC and GC/MS analysis of the oil resulted in the identification of 26 compounds, representing 99.6% of the oil; pulegone (49.8%), menthone (32.5%) and limonene (6.0%) were the main components. The samples were also subjected to a screening for their possible antioxidant activity by using 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene-linoleic acid assays. In the first case, the free radical scavenging activity of polar subfraction of deodorized methanol extract (DeMW) was superior to all other extracts. Especially polar extracts exhibited strongest activity than the non-polar extracts. In the case of linoleic acid system, oxidation of linoleic acid was effectively inhibited by non-polar (chloroformic) subfraction methanol extract (MC), where the oil was less effective. MC extract exhibits 79.2% inhibition that is close to synthetic antioxidant reagent BHT when compared to the other extracts tested.
Article
The antimicrobial properties of essential oils (EOs) have been recognised for centuries and, with growing demand from changes in legislation, consumer trends and increasing isolation of antibiotic resistant pathogens, alternatives to chemical-based bactericides need to be found. Citrus oils not only lend themselves to use in food but also are generally recognised as safe (GRAS) and have been found to be inhibitory both in direct oil and vapour form against a range of both Gram-positive and Gram-negative bacteria. This group of oils may provide the natural antimicrobials that the food industry requires to fulfil both its requirements and those of the consumer.
Article
The present work examines the content and chemical composition of the glycosidically bound volatiles from oregano as well as their antioxidative properties. The glycosidically bound volatiles amounted to 20 mg kg−1 in dried leaves and flowers of oregano. Fourteen volatile aglycones were identified with thymoquinone as the major component. Other important aglycones were benzyl alcohol, eugenol, 2-phenyl-ethanol, thymol, 3-hexen-1-ol and carvacrol. It was found that all of the aglycones have an antioxidant effect when tested by measuring peroxide values of lard stored at 60°C. These results were compared to the antioxidative activity of oregano essential oil, pure thymol, thymoquinone and also to α-tocoferol which is well known among natural antioxidant compounds.
Article
Applicability of solvent-free microwave extraction (SFME) in the extraction of essential oil from Origanum vulgare L. was examined and the effects of microwave power and extraction time on the yield and composition of the product were investigated. Specific gravity and refractive index of the essential oil and its solubility in alcohol were also examined. Hydrodistillation was performed as control. GC–MS/FID was used for the determination and quantification of aroma compounds in the essential oils. SFME offered significantly higher essential oil yields (0.054 mL/g) as compared to hydrodistillation (0.048 mL/g). When 622 W microwave power was used in SFME, conventional process time was reduced by 80%. The main aroma compound of oregano essential oil was found to be thymol (650–750 mg/mL). No significant differences were obtained in the compositions and physical properties of oregano essential oils obtained by SFME and hydrodistillation.