Citrus Essential Oils Research Articles

Influence of Citrus Essential Oils on the Microbiological, Physicochemical and Antioxidant Properties of Primosale Cheese.

The aim of this study was to produce a fresh ovine pressed cheese within Pecorino “Primosale” typology with the addition of citrus essential oils (EOs). For this purpose, ewe’s pasteurized milk was added with EOs from the peel of lemons, oranges and tangerines. Seven cheese productions were performed at the pilot plant scale level, including one control production (CP) without the addition of EOs and six experimental productions obtained by the addition of two EO concentrations (100 and 200 µL/L) to milk. The acidification process was obtained by means of the starter cultures Lactococcus lactis CAG4 and PON36. All cheeses showed levels of lactic acid bacteria (LAB) around 109 CFU/g, indicating that citrus EOs did not negatively influence the starter evolution. The addition of citrus EOs did not determine significant variations for dry matter, fat and protein percentages but increased the antioxidant capacity of all the experimental cheeses of about 50% in comparison to the control trial. The citrus EOs impacted cheese VOCs, especially for terpene class (limonene, β-pinene, myrcene, carene, linalool and α-terpineol). The sensory evaluation showed that cheeses enriched with 100 µL/L of citrus EOs were mostly appreciated by the panelists.

Authentication of Citrus spp. Cold-Pressed Essential Oils by Their Oxygenated Heterocyclic Components.

Citrus essential oils are routinely adulterated because of the lack of regulations or reliable authentication methods. Unfortunately, the relatively simple chemical makeup and the tremendous price variations among Citrus varieties encouraged the interspecies adulteration of citrus oils. In this study, a sensitive UPLC-MS/MS method for the quantitation of 14 coumarins and furanocoumarins is developed and validated. This method was applied to screen the essential oils of 12 different Citrus species. This study, to our knowledge, represents the most comprehensive investigation of coumarin and furanocoumarin profiles across commercial-scale Citrus oils to date. Results show that the lowest amount was detected in calamansi oil. Expressed oil of Italian bergamot showed the highest furanocoumarin content and the highest level of any individual furanocoumarin (bergamottin). Notable differences were observed in the coumarin and furanocoumarin levels among oils of different crop varieties and origins within the same species. Potential correlations were observed between bergapten and xanthotoxin which matches with known biosynthetic pathways. We found patterns in furanocoumarin profiles that line up with known variations among the Citrus ancestral taxa. However, contrary to the literature, we also detected xanthotoxin in sweet orange and members of the mandarin taxon. Using multivariate analysis, we were able to divide the Citrus oils into 5 main groups and correlate them to the coumarin compositions.

Effect of D-Limonene Nanoemulsion Edible Film on Banana (Musa sapientum Linn.) Post-Harvest Preservation.

D-limonene (4-isopropenyl-1-methylcyclohexene) is an important compound in several citrus essential oils (such as orange, lemon, tangerine, lime, and grapefruit). It has been used as a flavoring agent and as a food preservative agent, with generally recognized as safe (GRAS) status. D-limonene has been well-studied for its anti-inflammatory, antioxidant, anti-cancer, and antibacterial properties. The antibacterial activity of D-limonene against food-borne pathogens was investigated in this study by preparing a D-limonene nanoemulsion. The D-limonene solution and nanoemulsion have been prepared in six concentrations, 0.04%, 0.08%, 0.1%, 0.2%, 0.4%, and 0.8% (v/v), respectively, and the antibacterial activity was tested against four food-borne pathogens (Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica, and Escherichia coli). The results showed that the D-limonene nanoemulsion had good nanoscale and overall particle size uniformity, and its particle size was about 3~5 nm. It has been found that the D-limonene solution and nanoemulsion have a minimal inhibitory concentration of 0.336 mg/mL, and that they could inhibit the growth of microorganisms efficiently. The data indicate that the D-limonene nanoemulsion has more antibacterial ability against microorganisms than the D-limonene essential oil. After bananas are treated with 1.0% and 1.5% D-limonene nanoemulsion coatings, the water loss of the bananas during storage and the percentage of weight loss are reduced, which can inhibit the activity of pectinase. The application of a biocoating provides a good degree of antibacterial activity and air and moisture barrier properties, which help with extending the shelf life of bananas.

Cytotoxicity and antiproliferative activity of essential oils from lemon, wild orange and petitgrain against MCF-7, HepG2 and HeLa cancer cells

The purpose of this study was to determine the chemical composition and biological properties of the citrus essential oils (EOs) derived from orange rinds (peels) of lemon (Citrus limon), wild orange (Citrus sinensis) from Brazil extracted by the cold pressed/expressed method, and leaves and twigs of petitgrain (Citrus aurantium) from Paraguay extracted by steam distillation. These food grade EOs were evaluated for their cytotoxic activity in breast, liver, and cervical cancer cells (MCF-7, HepG2 and HeLa) via MTT assay, antiproliferative activity via colony formation assay, and antimigratory activity via wound healing assay, and apoptosis via DNA fragmentation and morphology assessment. The major compounds found in lemon EO were D-limonene (66.75%), beta-pinene (12.82%), and gamma-terpinene (11.57%), totaling over 90% of the identified compounds. For wild orange, the only predominant compound was limonene (96.60%), and the rest, found in minor amounts, included alpha-pinene, bicyclohexane, beta-pinene, beta-myrcene, 3-carene, and o-cymene. For petitgrain EO, linalyl isobutyrate (51.76%) and linalool (26.86%) were mainly detected. Based on the MTT assay, petitgrain EO was the most effective against MCF-7, HepG2 and HeLa. However, wild orange EO was the most antiproliferative and antimigratory against all three cells using the anticolony formation assay and wound healing assay, respectively. The results showed that cell death is associated with the apoptotic process, with morphological hallmarks of apoptosis including membrane blebbing and DNA fragmentation. These findings imply that the three citrus EOs might be used as active components in functional food products for chemopreventive benefits.

Peel Essential Oil Composition and Antibacterial Activities of Citrus x sinensis L. Osbeck ‘Tarocco’ and Citrus reticulata Blanco

Oranges and mandarins in Chongqing, China, are mostly processed for juice and their peels are wasted or landfilled. To add value, it is essential to utilize the peels and extract useful materials, such as citrus essential oils (CEOs). Here, we report the metabolome analysis of the peels of Citrus x sinensis (CS) and Citrus reticulata (CR). In total, 793 metabolites were detected in the CS and CR peels, of which 242 were differentially accumulated. The metabolites were grouped into 12 compound classes. Terpenoids were the highest accumulated class of compounds followed by phenols and alcohols in both fruit peels. CR peels were rich in all types of compounds, whereas CS showed a relatively lower content of the detected compounds. The highest accumulated compounds were β-phellandrene, beta-ocimene, 1,3,6-octatriene,3,7-dimethyl, and d-limonene. Overall, CR showed higher compound diversity than CS. The CS and CR peel extracts showed antibacterial effects against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis. The peel extracts from CR and CS showed similar antibacterial effects against E. coli and B. subtilis, while CS peel extracts were more effective against S. aureus. Overall, our study concludes that both CS and CR peels should not be wasted owing to the CEOs and respective antibacterial activities.

Phytochemical Screening, GC Analysis and Antibacterial Activity of Citrus limon Peel Extract and Essential Oil

Lemon (Citrus limon) is the most commonly grown tree fruit in the world. The fresh lemons were collected from the local market of Kathmandu, Nepal. Hexane and methanol extracts of plant material i.e. lemon peel were screened for the analysis of the presence of phytochemicals as well as their antibacterial activity. Methanol extract of lemon peel showed the maximum positive phytochemical test with the presence of alkaloids, flavonoids, polyphenols, terpenoids, glycosides, saponin, tannins etc. The essential oil was obtained by steam distillation from fresh peels of lemon using the Clevenger apparatus and analyzed by gas chromatography (GC). Twenty six (26) chemical components were identified in the essential oil of lemon peel. Lemon peel essential oil indicated the presence of Pinene (β) (15.46 %), Limonene (28.94 %), and Terpinene (γ) (8.64), Terpinen-4-ol (3.29 %), Neral (4.20 %), Geranial (5.28 %) as major components. The lemon peel essential oil was found to be a potent antibacterial agent against the Bacillus subtilis (21 mm).

Exploring the effect of a microencapsulated citrus essential oil on in vitro fermentation kinetics of pig gut microbiota.

Essential oils (EOs) have emerged as a potential alternative to antibiotics in pig breeding due to their antimicrobial properties. Citrus EOs, a common by-product of the orange juice industry, can be an interesting alternative from a financial perspective due to their huge offer in the global market. Thus, the effect of a citrus EO, and specifically different formulations of Brazilian Orange Terpenes (BOT), on pig gut microbiota was evaluated by means of an in vitro fermentation model simulating different sections of the pig gut (stomach, ileum, and colon). Treatments consisted in: BOT in its unprotected form (BOT, 1.85 and 3.70 mg/mL), microencapsulated BOT (MBOT, 3.50 and 7.00 mg/mL), colistin (2 μg/mL), and a control. BOT and MBOT altered in a similar way the total bacterial 16S rRNA gene copies in the stomach only from 18 h of incubation onwards, and no metabolite production in terms of short-chain fatty acids (SCFAs) was detected. In ileal and colonic fermentations, BOT and MBOT affected ileal and colonic microbiota in terms of total bacterial 16S rRNA gene copies, reduced phylogenetic diversity, and altered composition (p < 0.05) as evidenced by the significant reduction of certain bacterial taxa. However, more pronounced effects were found for MBOT, indicating its higher antimicrobial effects compared to the unprotected BOT, and suggesting that the antibacterial efficiency of the unprotected BOT was probably enhanced by microencapsulation. Furthermore, MBOT stimulated lactate production in ileal fermentations and greatly stimulated overall SCFA production in colonic fermentations. This indicates that besides the shifts in ileal and colonic microbiota by the delivered EO (BOT), the wall material of microcapsules (chitosan/modified starch) might have worked as an additional carbon source with prebiotic functioning, stimulating growth and metabolic activity (SCFAs) of colonic bacteria.

Environment-Friendly Control Potential of Two Citrus Essential Oils against Aphis punicae and Aphis illinoisensis (Hemiptera: Aphididae)

Aphids are serious pests of a wide range of agricultural crops, including pomegranates and grapevines. In addition, due to the negative environmental impacts of chemical insecticides, these pests are developing important resistance against aphicides. Therefore, one alternative method to control aphids is the use of essential oils (EO). The present study aimed to evaluate the insecticidal activity of Citrus aurantium and C. reticulata peel EO at different concentrations and with different exposure periods to pomegranate and grapevine aphids, Aphis punicae and A. illinoisensis via the topical application method under laboratory conditions. The results reveal that C. aurantium L. EO had greater toxicity against pomegranate and grapevine aphids, with LC50 of 0.37 and 0.82 μL/mL, respectively, at 48 h after application. The highest repellence effect was estimated for C. aurantium EO, at 2.5 μL/cm2, on A. punicae, with a value of 100% after an exposure time of 3 h, in contrast to the 88% repellence estimated for A. illinoisensis. The GC-MS investigation of both essential oils identified limonene, 3-carene, pinene, and p-cymene as active substances that could be attributed to the effects observed. Overall, our results offer a potential tool to control the two aphid species and could help in the development of integrated insect management in pomegranate and grapevine fields.

Rational construction of citrus essential oil nanoemulsion with robust stability and high antimicrobial activity based on combination of emulsifiers

We have successfully constructed citrus essential oil (CEO, d-limonene is its main active component) nanoemulsion by the high-pressure homogenization method, whose droplet size, polydispersity index, and zeta potential were 34.23 nm, 0.235, and −25.87 mV, respectively. The effects of thermal treatment (−20–48 °C), pH (5–9), ionic strength (100–500 mM NaCl) and storage time (200 days) were examined on the physicochemical properties of all treatments. The antimicrobial activity of nanoemulsion was tested by determining the minimal inhibitory concentration against the four foodborne microorganisms (Escherichia coli (10 mg/mL), Staphylococcus aureus (0.150 mg/mL), Bacillus subtilis (0.312 mg/mL) and Saccharomyces cerevisiae (0.312 mg/mL)). Especially, compared with pure CEO, the antibacterial activity of its nanoemulsion against S. aureus (0.150 mg/mL) and B. subtilis (0.312 mg/mL) was increased by 43 and 86 times respectively. Industrial relevance: In this work, we constructed robust CEO nanoemulsions based on a combination of emulsifiers via the high-pressure homogenization method, which bring new insights into the preparation of nanoemulsions. There is great potential for nanoencapsulation of natural compounds in the field of food preservation. Furthermore, the results may provide valuable data for industrial scale-up application.

Comparison of Supercritical Fluid Chromatography Hyphenated to an Ultraviolet Detector and Gas Chromatography Hyphenated to a Flame Ionization Detector for Qualitative and Quantitative Analysis of Citrus Essential Oils

A comparison between the classical gas chromatography (GC) technique with supercritical fluid chromatography (SFC) technology was performed using an essential oil of Citrus limon (lemon) as a model, considering its wide use in the cosmetic world. For the qualitative part, the signal annotation was achieved by mass spectrometry using either an electron ionization (EI) or an atmospheric pressure photoionization (APPI) source. For the quantitative part, GC was hyphenated to a flame ionization detector (GC-FID) and SFC to an ultraviolet detector (SFC-UV). The assay of the major component of citrus oil, i.e., limonene, was carried out by SFC-UV. The similar results obtained between GC-FID and SFC-UV allows SFC-UV to be considered as an alternative to GC-FID for Citrus oil characterization. Then, analyses of an essential oil collection from Citrus fruits were achieved to confirm the potential use of SFC-UV for oil classification in the context of quality control of raw materials in cosmetics.

Separation of Citrus Essential Oil and Hesperidin from Citrus Peel Through Combined Mixed-Solvent and Multi-Phase Salting Out Extraction

Large amounts of citrus peel are discarded as solid waste owing to the lack of recycling methods. In this study, mixed solvent extraction combined with multi-phase salting-out extraction was performed to explore the extraction process of essential oil and hesperidin. Optimal conditions were used for mixed solvent extraction (citrus peel 6%; ratio of ethanol to n-hexane 1:5; duration, stirring speed, and temperature were 150 min, 120 r/min, and 45°C, respectively) and multi-phase salting-out extraction (citrus peel residue 10%; ratio of salt to ethanol 19:24; mass fraction of n-hexane 25%; extraction duration 120 min). Under two-step extraction conditions, 63.74±2.40% essential oil and 27.13±1.36% hesperidin were recovered, with total extraction efficiencies of 5.19±0.09 and 1.91±0.25%, respectively. The amplification effect was not significant, and the organic solvents could be reused three times while maintaining 80% recovery in both steps to balance the commercial cost and extraction efficiency.

Citrus Essential Oils: a Treasure Trove of Antibiofilm Agent.

Biofilms are groups of adherent cell communities that cohere to the biotic and abiotic surfaces with the help of extracellular polymeric substances (EPS). EPS allow bacteria to form a biofilm that facilitates their binding to biotic and abiotic surfaces and provides resistance to the host immune responses and to antibiotics. There are efforts that have led to the development of natural compounds that can overcome this biofilm-mediated resistance. Essential oils (EOs) are a unique mixture of compounds that plays a key role in preventing the development of biofilm. The present overview focusses on the role of various types of citrus essential oils in acting against the biofilm, and the antibiofilm properties of natural compounds that may show an avenue to treat the multidrug-resistant bacteria.

Optimization of Citrus limon peel extraction, determination of main chemical components and effectiveness in repellency against Aedes mosquito dengue fever vector

Currently, scientific publications are focusing on the pharmacological actions of Citrus limon's extract and essential oil. Its essential oil is rich in bioactive monoterpenoids, such as D-limonene, β-pinene, γ-terpinene. Citrus limon essential oils have been recognized as the potential source of natural insecticides because of their selectivity, ability to be biologically degraded into non-toxic compounds, low impacts on biodiversity and the environment. Many previous studies have reported anti-bacterial, anti-fungal, anti-inflammatory, anti-cancer, hepato-regenerative, and cardio-protective activities of Citrus limon essential oil. In this study, we collected the discarded Citrus limon peel source in Gia Lai province to utilize as a material to build an optimized extraction process with the following criteria: extraction solvent, solvent/sample ratio, extraction temperature, and extraction time. The results showed a stable extraction process with a maximum extraction efficiency of 4.02%, at 40°C, for 3 hours, with two extraction times using 95% ethanol for solvent. Using GC/MS method, the determined limonene content accounted for 12.2% of the extract. The Citrus limon peel extract exhibited potency against Aedes aegypti (arbovirus vector) at a concentration of 0.01 mL, with protection time of 70 minutes and biting percentage of 0.9%, compared to negative control with statistically significant (P &lt; 0.05). The above results correspond with the most recent publications about the effects of mosquito repellence of certain plant-based essential oils. This study has proven that Citrus limon peel in this locality signifies a promising candidature for future studies regarding its main active compound, limonene, in the control of dengue-transmitting vectors. Therefore, Citrus limon peel extract brings hope to develop new mosquito repellency products in the future.

Insecticidal activity of the essential oil of Schinus areira against Rhipibruchus picturatus (F.) (Coleoptera: Bruchinae), and its inhibitory effects on acetylcholinesterase

During the storage of Prosopis alba pods, substantial quantitative and qualitative losses were observed. One of the main factors is the seed beetle Rhipibruchus picturatus. A key strategy to develop new pest control management is the use of essential oils (EOs) due they are efficient, less toxic, and less persistent in the environment compared to synthetic pesticides. In this context, seeds and leaves of Schinus areira L. (Anacardiaceae) EOs and Citrus spp. EO were studied in the present work. In the leaves of S. areira EO, 1-epi-cadinol, sesquiterpenoid alcohol, was the major compound. On the other hand, the main compounds of the EO extracted from S. areira seeds are the monoterpenes sabinene, and α-pinene. Finally, in the Citrus EO, limonene is the principal component. The three EOs obtained exhibited insecticidal activity against R. picturatus, being the first report of the use of EOs against this insect pest. The best insecticidal results were obtained with the leaves of S. areira EO. Moreover, this EO inhibits the acetylcholinesterase enzyme in vitro assays. Molecular docking studies on acetylcholinesterase (AChE) suggest that the main components of the leaves of S, areira EOs, bind to the active site of the enzyme, in good agreement with in vitro competitive inhibition against AChE observed for this EO. The data obtained demonstrate the potential use of Schinus areira EOs in the development of new storage pest control strategies.

Mandarin essential oil as an antimicrobial in ethanolic fermentation: Effects on Limosilactobacillus fermentum and Saccharomyces cerevisiae.

The antibacterial activity of citrus essential oils (EOs) in the context of combating Limosilactobacillus fermentum, one of the most important bacterial contaminants in the bioethanol production industry, has never been explored previously. Industrial processes usually utilize sulfuric acid for cell treatment to decrease bacterial contamination. However, due to the hazardous nature of sulfuric acid, an alternative to it is highly desirable. Therefore, in the present study, the efficacy of Fremont IAC 543 mandarin EO against a strain of L. fermentum (ATCC® 9338™) was evaluated under proliferative/nonproliferative conditions, in both pure culture and co-culture with an industrial strain of Saccharomyces cerevisiae. The mandarin EO exhibited higher effectiveness against L. fermentum compared to that against S. cerevisiae under nonproliferative conditions (added to water rather than to culture medium). At the concentration of 0·05%, the EO was as effective as the acid solution with pH 2·0 in reducing the count of L. fermentum almost 5 log CFU ml-1 cycles, while the concentration of 0·1% led to the complete loss of bacterial culturability. When L. fermentum was co-cultured with S. cerevisiae, the efficacy of the EO against the bacterial strain was reduced. However, despite this reduced efficacy in co-culture, mandarin EO may be considered effective in combating L. fermentum and could be applied in processes where this bacterium proves to be unfavourable and does not interact with S. cerevisiae.

A Comparative Study on Relieving Exercise-Induced Fatigue by Inhalation of Different Citrus Essential Oils.

Citrus essential oils (CEOs) possess physiological functions due to diverse aroma components. However, evidence for the effects of CEOs on exercise performance and exercise-induced fatigue is limited. The CEOs with discrepancies in components may exert different effects on the amelioration of exercise-induced fatigue. In this study, sweet orange (Citrus sinensis L.) essential oil (SEO), lemon (Citrus limon Osbeck) essential oil (LEO), and bergamot (Citrus bergamia Risso and Poit) essential oil (BEO) were chosen to explore the effect on amelioration of exercise-induced fatigue. Our results demonstrated that SEO and LEO increased the swimming time by 276% and 46.5%, while BEO did not. Moreover, the three CEOs exerted varying effects on mitigating exercise-induced fatigue via inhibiting oxidative stress, protecting muscle injury, and promoting glucose-dependent energy supply. Accordingly, BEO showed the best efficiency. Moreover, the GC-MS and Pearson correlation analysis of BEO showed that the contents of the major components, such as (±)-limonene (32.9%), linalyl butyrate (17.8%), and linalool (7.7%), were significantly positively correlated with relieving exercise-induced fatigue.

Chemical constituents, biological activities and anti-rheumatoid arthritic properties of four citrus essential oils.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease with predominant synovitis that has no complete cure or preventive treatment. Citrus essential oils, used in natural fragrances, contain a variety of functional ingredients that are worthy of investigation for their potential as natural anti-inflammatory drug sources. In this study, essential oils were hydro distilled from the peels of four citrus species: Citrus sinensis (L.) Osbeck (CSEOs), Citrus paradisi Macfad. (CPEOs), Citrus limon (L.) Osbeck (CLEOs) and Citri Reticulatae Pericarpium (CREOs). Altogether, 81 compounds were identified using gas chromatography-mass spectrometry (GC-MS), of which d-limonene (17.96%-94.66%) was an abundant component of all four oils. The stable 1,1-diphenyl-2-pyrrole hydrazine (DPPH) free radical test showed that all four essential oils had excellent antioxidant properties (IC50 , 0.76-13.86 μg/mL). Furthermore, the oils remarkably increased the first G1 phase of the cell cycle, which inhibited the pro-inflammatory factor expression. An immunohistochemical analysis indicated that the four essential oils inhibited the expression of tumor necrosis factor-α and cyclooxygenase-2 and they exhibited anti-inflammatory activity in a rat model that was similar to that of the common drug, Ibuprofen. These results show that the CSEOs, CPEOs, CLEOs, and CREOs have significant antirheumatic activities and thus have great potential in developing functional food or drugs for treating RA.

Recovery of Orange Peel Essential Oil from ‘Sai-Namphaung’ Tangerine Fruit Drop Biomass and Its Potential Use as Citrus Fruit Postharvest Diseases Control

In this study, we assessed the quality of essential oil recovered from fruit drop biomass and assessed its usefulness in preventing postharvest diseases in the tangerine ‘Sai-Namphaung’. Greening was the primary cause of the fruit drop, based on the enduring symptoms and occurrence of the disease in the area. Limonene, together with the presence of β-pinene and linalool, was discovered to be prevalent in essential oils of tangerine fruit peel, particularly that of ‘Sai-Namphaung’. Through isolation of citrus postharvest fungi, we were able to identify four genera which were later DNA sequenced using Internal Transcribed Spacer: ITS and subjected to Basic Local Alignment Search Tool (BLAST), with a high possibility (&gt;98% similarity) of being Penicillium digitatum, Colletotrichum gloeosporioides, Fusarium sarcochrum and Geotrichum candidum. Essential oil from ‘Sai-Namphaung’ and ‘Fremont’ peel biomass positively inhibited green mold rot and citrus anthracnose caused by P. digitatum, C. gloeosporiodes, but were less effective than the commercial citrus oil and Zanthoxylum myriacanthum oil. This is the first evidence of ‘Sai-Namphaung’ postharvest diseases caused by these two fungi and their controls using citrus essential oil.

Supercritical fluid chromatography-tandem mass spectrometry of oxygen heterocyclic compounds in Citrus essential oils.

Oxygen heterocyclic compounds are secondary metabolites mainly present in the non-volatile fraction of cold-pressed Citrus essential oils. Under this denomination are included coumarins, furocoumarins, and polymethoxyflavones. These compounds possess numerous beneficial properties for human health, but the ingestion of large amounts of coumarins is often related to toxic effects, whereas the phototoxicity caused by furocoumarins and UVA exposure has been well known for a long time. This research has been aimed at the validation of an analytical approach, based on supercritical fluid chromatography coupled to tandem mass spectrometry, for the analysis of OHCs in Citrus essential oils. Among eight columns tested, packed with different stationary phases, the pentafluorophenyl allowed the best baseline separation in 8min and by using less than 10% of methanol. Calibration curves of twenty-eight standards (coumarins, furocoumarins, polymethoxyflavones) were constructed on spiked lemon distilled essential oil and the method was validated according to the EURACHEM guidelines, by calculating linearity, limit of detection (LoD), limit of quantification (LoQ), accuracy, intra-day, and inter-day precision. Specifically, recoveries were in the 80.0-118.6% range, regression coefficients were between 0.9904 and 0.9998, the LoDs were in the 0.0004-0.0470mgkg-1 range, the LoQs were in the 0.0014-0.1536mgkg-1 range, and coefficients of variation were between 0.3 and 2.6% (intra-day) and 1.1 and 7.4% (inter-day). The quantitative profiles of thirteen cold-pressed Citrus essential oils were determined.

Essential Oils in Citrus Fruit Ripening and Postharvest Quality

Citrus essential oils (EOs) are widely used as flavoring agents in food, pharmaceutical, cosmetical and chemical industries. For this reason, their demand is constantly increasing all over the world. Besides industrial applications, the abundance of EOs in the epicarp is particularly relevant for the quality of citrus fruit. In fact, these compounds represent a natural protection against postharvest deteriorations due to their remarkable antimicrobial, insecticidal and antioxidant activities. Several factors, including genotype, climatic conditions and cultural practices, can influence the assortment and accumulation of EOs in citrus peels. This review is focused on factors influencing variation of the EOs’ composition during ripening and on the implications on postharvest quality of the fruit.