Citrus Fruit Species Research Articles

Characterization and Identification of Neocosmospora solani and Fusarium oxysporum Causing Root Necrosis and Wilting of Orange Trees in Chile

Orange trees (Citrus × sinensis (L.) Osbeck) are the third-most cultivated citrus fruit species in Chile. In recent years, several trees in three orange orchards of ‘Lane late’ and ‘Fukumoto’ cultivars grafted on ‘Robidoux’ trifoliate orange (Poncirus trifoliata (L.) Raf.) have shown chlorosis, canopy reduction, wilting, root necrosis, defoliation, and plant death symptoms. This study aims to characterize the morphological symptoms observed in diseased orange trees in central Chile and identify the fungal pathogens that are involved. Isolation and morphological characterization of the pathogens were conducted by using different culture media. A total of 53 isolates were obtained, morphologically characterized and 12 isolates were selected for molecular identification. The isolates were identified using ITS, TEF-1α, and RPB2 regions. Two Fusarium species complexes were identified, Neocosmospora (Fusarium) solani (FSSC) and F. oxysporum (FOSC), based on >99% identity. Pathogenicity tests were conducted on young orange seedlings under greenhouse conditions. Results indicated that two months post inoculation, trifoliate orange seedlings displayed root rot symptoms such as necrosis, vascular discoloration, and wilting. FSSC and FOSC were re-isolated from necrotic seedling roots and identified through a combination of morphological traits and molecular techniques. This is the first detailed report of this disease, attributed to FSSC and FOSC, in orange orchards in Chile. These diagnostic results represent the first step in developing adequate phytosanitary programs for managing this disease.

Antifungal activities of some citrus essential oils against Pyricularia oryzae

Rice is a staple food worldwide because many families depend on it as an everyday source of food. However, there are some agents posing as threat to the availability of rice worldwide thereby threatening food security. Pyricularia oryzae is a fungal agent notable for causing rice blast disease thereby causing shortage in the production of rice. Essential oils (EOs) from peels (fresh and dried) of three species of citrus fruit (lime, grapefruit and tangerine) were investigated for their antifungal activity against P. oryzae. The EOs were extracted and analysed for their composition using standard analytical techniques. Their antifungal activities were also tested on potato dextrose agar (PDA) medium using disc diffusion method and the results obtained were compared with standard antifungal agents. Dried tangerine EO had the highest fungal mycelial growth inhibition (90%) which was followed by fresh tangerine EO (76.2%). The compounds detected in the essential oils composed majorly hydrocarbons and oxygenated hydrocarbons with limonene, beta myrcene and alpha terpineol detected in fairly high amount in all the investigated essential oils. This study, shows that the peels of these citrus fruits could be of great importance in combating the scourge of P. oryzae, reducing the occurrence of rice blast disease, enhancing rice availability as a staple food and by extension, ensuring food security. These attributes highlight the potential benefits of citrus fruit peels instead of regarding them as mere waste materials.

Antimicrobial activities of essential oils from three species of citrus fruits against six infectious tropical bacteria: implications for the care and control of common bacterial tropical diseases in developing countries

The burden of bacterial infections and the failure of antimicrobial agents are increasing worldwide, especially in sub-Saharan Africa. This raises the need for novel therapeutic agents to combat bacterial infectious diseases. The sensitivity of several common pathogenic bacteria to essential oils from the peels of three species of citrus plants was investigated. Essential oils (EOs) were extracted from the fresh and dried peels of the citrus species using standard techniques. The antimicrobial activities of the EOs were determined using agar well diffusion and broth microdilution methods, and the activities of the EOs were compared to those of twelve conventional antibiotics. The results showed that the essential oils had high inhibitory effects. The minimum inhibitory concentrations (MICs) of the EOs ranged between 0.025 and 0.15 mg/ml. The activities of the EOs against the tested microorganisms were comparable to those of conventional antibiotics. Processing techniques did not affect the antibacterial activities of the EOs. Thus, the essential oils from the citrus species used against the investigated microorganisms were comparable to conventional antibiotics, and these findings showed that the oils could be widely applied in the health and pharmaceutical industries, where they could help in combating the menace of bacterial infections and therapeutic failure from drug resistance worldwide and especially in developing countries with limited resources available to combat these infections.

Potent Hypoglycemic Phytochemicals from Citrus

In particular, when it comes to the cure and management of chronic diseases, consuming a diet that contain natural products such as; plants is crucial for health promotion. Citrus fruit has been widely consumed and possess nutritional components that supports the management and cure of various disease conditions and the underlying metabolic changes that leads to development of long term serious diseases. Multiple citrus fruit species are analyzed for their curative effect particularly for the diseases that are associated with metabolic alterations such as diabetes, heart burn and dyspepsia. Diabetes is found to be effectively cured and allied health problems are managed by the use of citrus fruits and the specific secondary metabolites found in citrus fruits such has; hesperidin, naringenin and nobiletin. Citrus fruits primarily contain flavonoids, which have a number of advantageous properties for health promotion, especially anti-diabetic effects. Present review enlightened the specific curative potential of citrus fruits and phytochemicals on the living organisms, the potential anti-diabetic efficacy and the metabolic pathway of citrus bioactive compounds hesperidin and naringenin is explained. Mechanistic regulation of metabolic disturbances owing to various disease conditions that are root caused by diabetes are effectively done by the bioactive compounds of citrus fruits. Citrus fruits have matchless benefits when it comes the issues of hyperglycemia, while their antidiabetic effects and have ameliorative effect on diabetes related health problems remain to be verified in detail at molecular and clinical level in forthcoming studies.

A New Ready-to-Eat Product Based on Enzymatically Peeled 'Hernandina' Clementine Segments and Citrus Syrup.

Ready-to-eat fresh fruit have an increasing presence in international markets due to their convenience and health benefits. However, these products are highly perishable and efficient technologies to increase their shelf life are needed. In the present research, different citrus fruit species and cultivars from organic farming were assessed to obtain enzymatically peeled citrus segments. The best results in terms of segment quality were observed for 'Hernandina' clementine, which was chosen to make a new ready-to-eat product based on peeled citrus segments that were packaged in glass jars with a light syrup made of citrus juice and organic sugar cane. Different citrus juice mixtures were assayed and the most appreciated syrup, based on the sensory scores given by panellists, was that containing 50-50 (v/v) of 'Fino' lemon and 'Hernandina' clementine juices. In addition, different pasteurization treatments were assessed for their effects on conserving the safety, nutritional quality and sensory properties of the product during cold storage. The results show that pasteurization treatment at 50 °C for 45 min was sufficient to prevent microbial contamination with mesophilic and psychrophilic aerobic bacteria or yeast and mould and to maintain sensory properties until five weeks of storage at 4 °C. In addition, only a 10% reduction in vitamin C concentrations was observed in fresh-segments or syrup until the end of the storage period, showing that a high bioactive compound content and health benefits were conserved in the new ready-to-eat product after pasteurization and prolonged cold storage.

Morphological and molecular identification of fungi for their association with postharvest fruit rots in some selected citrus species

Purpose: The availability of fresh Citrus fruits is limited by their susceptibility to invasion by microbial pathogens which leads to cause serious postharvest losses. The present study was carried out to isolate and morphologically identify postharvest fungal associations from selected Citrus fruit species (C. sinensis, C. limon, C. crenatifolia and C. medica) and to confirm their identity by molecular characterization. Research method: Postharvest fungal associations of selected Citrus fruit species were isolated, and identification was done based on morphological characteristics. Confirmation of fungal associations was done through phylogenetic analysis of newly generated ITS sequencing data. Further, frequency of occurrence of each fungal isolate was calculated in three different districts in Sri Lanka. Findings: From the morphological and molecular identification, Collectrichum fructicola, Collectrichum gloeosporioides, Lasiodiplodia theobromae, Aspergillus niger and Pestalotiopsis sp. were recorded from C. sinensis. Neofusicoccum parvum, Collectrichum gigasporium and Aspergillus clavatus were isolated from C. crenatifolia. Further, Lasiodiplodia theobromae and L. pseudotheobromae were the only fungal association isolated from C. limon and C. medica fruit species, respectively. It is worthwhile noting that this is the first report of association of the C. gigasporium and Pestalotiopsis sp. from Citrus fruits in Sri Lanka. Research limitations: Since this research was mainly focused on the isolation and identification of the potential fungal associations, pathogenicity evaluation could not be carried out. Originality/Value: Findings of potential disease causative agents in citrus will be valuable for agriculture sector, to adopt and practice effective strategies to minimize postharvest losses of citrus fruits.

Effect of citrus fruit (Citrus sinensis, Citrus limon and Citrus aurantifolia) rind essential oils on preservation of chicken meat artificially infected with bacteria

Essential oils (EOs) obtained from a wide variety of plants have become popular with increased scientific interest as potential natural agents for food preservation. Two concentrations of rind EOs (400 mg/ml and 200 mg/ml) from three species of citrus fruit; Citrus sinensis (Sweet orange), Citrus limon (Lemon), and Citrus aurantifolia (Lime) were used to treat fresh chicken meat inoculated with Escherichia coli ATCC 25922, Salmonella typhi ATCC 20971 and Salmonella enterica ATCC 14028 to evaluate their protective abilities on bacteria-contaminated meat The EOs were extracted from the ground rinds by hydro-distillation. Alongside the EOs, sodium nitrate (NaNO3) was used as a positive control preservative. A viable count was carried out to determine the bacteria load reduction on the inoculated fresh chicken meat. After 24 hours of treatment, the results showed that the EOs had no adverse effect on the physical attributes of the meat: the color and smell of the chicken meat were unaltered compared with the negative control (None EO and NaNO3 treated meat) that showed evidence of putrefaction through color change and foul smell. The two- lime rind EOs concentrations used to treat the Escherichia coli ATCC 25922 inoculated meat reduced the viable count of the organism by 7.9 log compared to the Escherichia coli ATCC 25922-inoculated meat which received no rind EOs or NaNO3 treatment. Other results showed that sweet orange (SO) rind EOs (400 mg/ml and 200 mg/ml) treatment of meat inoculated with Salmonella enterica ATCC 14028 had similar but mild preservative effects as both treatments reduced the log of the bacteria by 1.1 and 0.8, respectively. In comparison with NaNO3, the EOs treatment had a significant (p<0.05) preservative effect on the bacteria-inoculated meats. Findings from this study, therefore, suggest that Citrus spp. rind EOs have good potential as natural preservative for chicken meat. However, notwithstanding the relative positive organoleptic results observed in this study, further investigations on the prolonged preservation effect of the EOs on the physical attributes of fresh chicken meat need to be undertaken.

Physiological disorders of selected Citrus fruit species in Sri Lanka and their effect on fruit quality

PurposeThis study was conducted to identify the physiological disorders and their symptoms of selected Citrus fruit species (C. sinensis, C. limon and C. crenatifolia). Furthermore, it was aimed to determine whether physicochemical and sensory properties were affected by physiological disorders.Research methodCitrus fruits with physiological disorderswere observed separately for visible changes and characters were recorded and photographed. Moreover, Citrus fruits with physiological disorders were analyzed for physicochemical and sensory properties.FindingsMany physiological disorders were recorded from three Citrus fruit species including chilling injury, sun burn, stem-end rind breakdown, oleocellosis, rind disorder, puff and crease, granulation, wind injury, peteca, fruit splitting and fruit cracking. Based on the overall result of sensory analysis, it can be concluded that most of the physiological disorders in studied Citrus species appear on the peel but not adversely affect the edible internal portion of the fruits. Physicochemical properties of C. limon are not adversely affected by physiological disorders whereas C. sinensis and C. crenatifolia are affected by physiological disorders.Limitations: Availability of selected Citrus fruit species throughout the year is limited due to their seasonality.Originality/Value: This study provides novel information about the physiological disorders of some Citrus species in Sri Lanka and other parts of Asia and a future potential exists in controlling these disorders to provide healthy and quality fruits to the market.

Diversity of citrus germplasm in the Black Sea Region in Turkey

The Black Sea Agricultural region represents 12.59% of Turkey's fruit production and particularly the East Black Sea region ranks as 3rd in citrus fruit production after the Mediterranean and Aegean regions. Due to climate, soil and geographical features, production is mainly focused on hazelnut and tea. In Turkey, the citrus fruit production in the Mediterranean and Aegean regions is economical because of the ecological conditions of these regions. However, Satsuma mandarin which has the highest export finds its best ecology in the East Black Sea Region. In addition to mandarin, local citrus fruit species produced also include orange, lemon, citron and grapefruit. Nevertheless, due to increasing rate of tea production in this region, citrus fruit orchards have been destroyed and biodiversity has been threatened. In this paper, citrus germplasm in the East Black Sea region is evaluated and protection approaches are discussed.

LOCAL regression applied to a citrus multispecies library to assess chemical quality parameters using near infrared spectroscopy.

The non-destructive on-tree measurement of the chemical quality attributes of fruits belonging to the Citrus genus using rapid spectral sensors is of vital interest to citrus growers, allowing them to carry out a selective harvest of any species of Citrus fruit. With this objective, the viability of using of a handheld portable near infrared spectroscopy (NIRS) instrument to predict soluble solid content (SSC), pH, titratable acidity (TA), maturity index and BrimA, in order to measure the optimum harvest time in a group made up of 608 samples belonging to the Citrus genus (378 oranges and 230 mandarins) was evaluated. For each of the parameters analysed, both non-linear regression (LOCAL algorithm) and linear regression (Modified Partial Least Squares, MPLS) strategies were designed and compared. The use of the LOCAL algorithm in the sample group of oranges and mandarins for all the parameters analysed allowed to obtain more robust models than those obtained with MPLS regression, and it could also be extended more easily when routinely applied. The results confirm that NIRS technology combined with non-linear regression strategies such as the LOCAL algorithm can indeed respond to the needs of the Citrus growers and help them to set the optimum harvest time, in this case of oranges and mandarins, by predicting the chemical quality parameters in situ.

Growth inhibitory activities of extracts from peels of five species of citrus fruit on bacterial isolates obtained from rotten tomato fruits.

This study was undertaken to verify the efficacies of phytochemical extracts of citrus fruit peels obtained from Citrus sinensis, Citrus reticulata, Citrus limonum, Citrus aurantifolia and Citrus vitis against isolates of tomato rot bacteria. Results of this study provide the much needed less hazardous, cheap and readily available means of controlling or managing bacterial diseases of postharvest tomato fruits to reduce the huge economic losses often incurred by tomato fruits dealers and farmers. Solvent extracts were characterized for presence of constituent active compounds, flavonoids, tannins, terpenes, cardiac glycosides, anthraquinones, saponins and alkaloids. Pseudomonas spp., Klebsiella spp. and Escherichia coli were isolated from rotten tomato fruits using McConkey, Blood and Peptone Sucrose agar media. Isolates were subjected to sensitivity test with 10%, 20%, 30% and 40% concentrations (volume by volume) of the different extracts, respectively. All the concentrations showed different degrees of growth inhibition on the test organisms. The study confirmed that phytochemical extracts from peels of citrus fruits are efficacious against tomato fruit rot bacteria and therefore have a good promise for sustainable control of bacterial rot disease of tomato fruits.

The effects of transportation temperature on the decay rate and quality of postharvest Ponkan (Citrus reticulata Blanco) fruit in different storage periods

Abstract Ponkan (Citrus reticulata Blanco cv. Ponkan) is one of the widely grown and economically important citrus fruit species in China. Present study investigated the dynamic changes of Ponkan fruit’ storability in different storage period and under alternating temperature during the postharvest transportation and shelf life, aiming to find out an efficient and energy-saving transportation scheme for Ponkan fruit at different storage stage. The results showed that, the elongation of storage time and the higher transport temperature led to the increase of decay rate. The juice yield continued to decrease, without affecting by the transportation temperatures. The rind color turn yellow rapidly (with the citrus color index (CCI) increased from 3.61 to 9.25) during the first two months, and remained stable during the following period. The higher transportation temperature accelerated the rind color development. The total soluble solids (TSS) increased during the first month (from 11.21% to 13.25%), remained stable in the second and third months, and then decreased slightly in the fourth month, which was not evidently influenced by the transportation temperature. The titratable acidity (TA) showed a continuous decline which was accelerated by the high transportation temperature. The ethanol and aldehyde contents continue to increase and were not significantly affected by the transportation temperature. The total flavonoids content decreased during the transportation and shelf life of the newly harvested Ponkan fruit, while remained stable and was not significantly affected by the transportation temperature in the four months of storage. The alternating temperature of transportation affected the storability of Ponkan fruit at different storage periods. These finding provided a theoretical basis for the selection of transportation temperature from economic perspective.

Kontribusi Pendapatan Usahatani Jeruk Siam terhadap Pendapatan Rumah Tangga Petani di Desa Tegalsari, Kecamatan Tegalsari, Kabupaten Banyuwangi

Contribution of Tangerine Farming Revenue in Relation with the Total Household Income of Farmers in the Tegalsari Village, Tegalsari District,Banyuwangi Regency
 Tangerine, or also known as jeruk keprok in Bahasa, is one of the many species of citrus fruit which has been widely cultivated in various regions in Indonesia. Although its market fluctuate from time to time, but the public interest in tangerine never disappeared.This study aims to determine the contribution of tangerine farming revenue in relation with the total household income of the farmers in the Komojoyo Farmer Group. The results of this research obtained that the average tangerine farming revenue is Rp 35,000,000 per year while the average of non-farming revenue is amounted to Rp. 8,761,304 per year. It proved that citrus farm revenue is greater than non-farm revenue. There are constraints faced by Komojoyo Farmer Group, namely, the aphid pest, the lack of guidance from agricultural counselor, and sales methods are still using the services of middlemen. It can be evidenced from the percentages obtained: the pest was 11%, guidance from agricultural counselor at 65%, and sales of middlemen by 24%. From these percentages, it can be seen that the biggest obstacle faced by Komojoyo farmer group is the lack of guidance from agricultural counselor.

Analysis of volatile fraction of sweetie (Citrus maxima\u2009\xd7\u2009Citrus paradisi) and its parent fruit using proton transfer reaction mass spectrometry

The quality of the fruit is affected by several main ingredients and the aroma plays a fundamental role during the selection of fruit by consumers. In the case where several fruit have similar aromas and only one of them has specific health properties, it is very important to find the differences in the volatile organic compounds (VOCs) composition to distinguish these samples. Such situations are often found for hybrid fruit. Sweetie is a hybrid of grapefruit and pummelo. Sweetie fruit is characterized by high antioxidant potential and a positive effect on human health. The aim of this study was to verify the unique volatile compositional traits of three species of citrus fruit. Proton transfer reaction Time-of-Flight mass spectrometry (PTR-TOF-MS) was utilized to obtain the mass-resolved fingerprints of VOCs. The chemical formula of these VOC masses was tentatively identified. Principal component analysis was performed to evaluate the differences between the groups.Graphical abstract

Pectolinarigenin Induced Cell Cycle Arrest, Autophagy, and Apoptosis in Gastric Cancer Cell via PI3K/AKT/mTOR Signaling Pathway.

Pectolinarigenin (PEC), a natural flavonoid present in Cirsium chanroenicum and in some species of Citrus fruits, has various pharmacological benefits such as anti-inflammatory and anti-cancer activities. In the present study, we investigated the anti-cancer mechanism of PEC induced cell death caused by autophagy and apoptosis in AGS and MKN28 human gastric cancer cells. The PEC treatment significantly inhibited the AGS and MKN28 cell growth in a dose-dependent manner. Further, PEC significantly elevated sub-G1 phase in AGS cells and G2/M phase cell cycle arrest in both AGS and MKN28 cells. Apoptosis was confirmed by Annexin V and Hoechst 33342 fluorescent staining. Moreover, Immunoblotting results revealed that PEC treatment down-regulated the inhibitor of apoptosis protein (IAP) family protein XIAP that leads to the activation of caspase-3 thereby cleavage of PARP (poly-ADP-ribose polymerase) in both AGS and MKN28 cells in a dose-dependent manner. The autophagy-inducing effect was indicated by the increased formation of acidic vesicular organelles (AVOs) and increased protein levels of LC3-II conversion in both AGS and MKN28 cells. PEC shows the down regulation of PI3K/AKT/mTOR pathway which is a major regulator of autophagic and apoptotic cell death in cancer cells that leads to the down-regulation of p-4EBP1, p-p70S6K, and p-eIF4E in PEC treated cells when compared with the untreated cells. In conclusion, PEC treatment might have anti-cancer effect by down-regulation of PI3K/AKT/mTOR pathway leading to G2/M phase cell cycle arrest, autophagic and apoptotic cell death in human gastric cancer cells. Further studies of PEC treatment can support to develop as a potential alternative therapeutic agent for human gastric carcinoma.

Naringin-loaded Poly(ε-caprolactone)/Gelatin Electrospun Mat as a Potential Wound Dressing: In vitro and In vivo Evaluation

In the present study, naringin, a flavonoid isolated from the grape and citrus fruit species, was incorporated with poly(e-caprolactone)/gelatin composite mats in order to develop a potential wound dressing. The composite mats were prepared by electrospinning of poly(e-caprolactone)/gelatin (1:1 (w/w)) solution incorporated with 1.50 %, 3 % and 6 % (w/w) of naringin. The electrospun mats were evaluated regarding their morphology, contact angle, water-uptake capacity, water vapor transmission rate, tensile properties, drug release, cellular response and in vivo wound healing activity. The study showed that after 2 weeks, the full-thickness excisional wounds of Wistar rats treated with the naringin-loaded dressings achieved a wound closure of higher than 94 % and the dressing containing 6 % (w/w) naringin had almost 100 % wound closure. The sterile gauze, as the control group, showed nearly 86 % of wound closure after this period of time. Our results provided evidence that supports the possible applicability of naringin-loaded wound dressing for successful wound treatment.

Comparative Analysis of Nutritional and Anti Nutritional Components of Selected Citrus Fruit species

Comparative Analysis of Nutritional and Anti Nutritional Components of Selected Citrus Fruit species

Phylogenetic study of the Colletotrichum species on imported citrus fruits uncovers a low diversity and a new species in the Colletotrichum gigasporum complex

Colletotrichum species associated with citrus fruits are fragmentarily known and it lacks accordingly accurate information on the diversity carried alongside the trade of these commodities from producer countries to Europe. In this study, we investigated the molecular phylogenetic diversity, colonisation, and prevalence of Colletotrichum isolated from asymptomatic and diseased tissues of nine citrus fruit species from 17 geographically diverse countries. Totally 454 isolates were morphoculturally characterised, and multilocus analyses (ACT, ApMat, CHS-1, GAPDH, ITS, TUB2) was performed on a subset of representative morphotype isolates. Results led to the identification of three previously known species (Colletotrichum gloeosporioides, Colletotrichum karstii, Colletotrichum siamense) and one novel lineage comprising endophytic isolates from Citrus maxima. Based on this lineage, Colletotrichum citri-maximae is described as a new species in the Colletotrichum gigasporum complex, and is characterised by a long deletion in the GAPDH sequence, a character shared with three of its phylogenetic sister taxa. Prevalence of Colletotrichum varied among citrus species and was greatest on Citrus sinensis fruits. C. gloeosporioides was the most common species followed by C. siamense. Except for the new species, all other isolated Colletotrichum spp. also colonise citrus leaves, but the overall diversity on fruits may be lower than that of leaves.

Fatty acids, tocopherols, phenolic and antioxidant properties of six citrus fruit species: a comparative study

Citrus fruit is a rich source of bioactive phytochemicals. Information on the fatty acid and tocopherol composition of locally grown citrus fruits in Korea is elusive. This work was aimed to study fatty acid, tocopherols, ascorbic acid, antioxidant potential, and selected phenolics from peel and pulp of six citrus species. The most dominant fatty acid was linoleic acid (15–45%), followed by linolenic, palmitic, and oleic acid. Stearic acid was highly abundant in yuzu peel (14.45%) and pulp (15.88%) compared to the other fruits. Unsaturated fatty acids (54–74%) contributed higher composition than saturated fatty acids (25–46%). Peel exhibited better antioxidant potential and contained higher phytochemicals than pulp. The concentrations of α-tocopherol and γ-tocopherol were ranged from 22.96 (yuzu) to 86.93 (cheonhyeyang) and 38.59 (yuzu) ~83.03 (tangerine) μg/g DW, respectively. J-Redhyeyang peel exhibited highest total flavonoids (4.17 ± 0.10 mgQE/g DW) and DPPH radical scavenging activity (6.17 ± 0.03 mgTE/g DW). FRAP values were highest (20.05 ± 0.64 mgTE/g DW) in yuzu peel, while peel of cheonhyeyang was superior in total phenolic contents. Tangerine (3.02 ± 0.05 mg/g DW) and yuzu (7.49 ± 0.38 mg/g DW) had higher hesperidin concentrations in pulp and peel, respectively. Naringin was found in an appreciable amount in yuzu pulp (2.04 ± 0.09 mg/g DW) and peel (6.30 ± 0.19 mg/g DW) but not detected in all other fruit species. Our results indicate that citrus fruit peel is the rich source of antioxidant compounds, which can be used to prepare antioxidant rich food product.

Determination of Volatile Flavour Profiles of Citrus spp. Fruits by SDE-GC-MS and Enantiomeric Composition of Chiral Compounds by MDGC-MS.

Citrus fruits are known to have characteristic enantiomeric key compounds biosynthesised by highly stereoselective enzymatic mechanisms. In the past, evaluation of the enantiomeric ratios of chiral compounds in fruits has been applied as an effective indicator of adulteration by the addition of synthetic compounds or natural components of different botanical origin. To analyse the volatile flavour compounds of Citrus junos Sieb. ex Tanaka (yuzu), Citrus limon BURM. f. (lemon) and Citrus aurantifolia Christm. Swingle (lime), and determine the enantiomeric ratios of their chiral compounds for discrimination and authentication of extracted oils. Volatile flavour compounds of the fruits of the three Citrus species were extracted by simultaneous distillation extraction and analysed by gas chromatography-mass spectrometry. The enantiomeric composition (ee%) of chiral camphene, sabinene, limonene and β-phellandrene was analysed by heart-cutting multidimensional gas chromatography-mass spectrometry. Sixty-seven (C. junos), 77 (C. limon) and 110 (C. aurantifolia) volatile compounds were identified with limonene, γ-terpinene and linalool as the major compounds. Stereochemical analysis (ee%) revealed 1S,4R-(-) camphene (94.74, 98.67, 98.82), R-(+)-limonene (90.53, 92.97, 99.85) and S-(+)-β-phellandrene (98.69, 97.15, 92.13) in oil samples from all three species; R-(+)-sabinene (88.08) in C. junos; and S-(-)-sabinene (81.99, 79.74) in C. limon and C. aurantifolia, respectively. The enantiomeric composition and excess ratios of the chiral compounds could be used as reliable indicators of genuineness and quality assurance of the oils derived from the Citrus fruit species. Copyright © 2017 John Wiley & Sons, Ltd.