Genetic improvement of Citrus fruits: The essential oil profiles in a Citrus limon backcross progeny derived from somatic hybridization

The peel essential oil profiles of an interspecific allotetraploid somatic hybrid, achieved by protoplast fusion of the ‘Valencia’ sweet orange (Citrus sinensis L. Osbeck) and ‘Femminello’ lemon (Citrus limon L. Burm), and three sexual hybrids obtained by back crosses between Femminello lemon and the allotetraploid somatic hybrid (Valencia + Femminello), have been studied by gas chromatography (GC) combined with a flame ionization detector (FID) and a mass spectrometry (MS). In total, 83 components were fully characterized and grouped in four classes (monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes, and others) for an easier comparison of all oils. A statistical treatment by linear discriminant analysis (LDA) of the compositional data from the allotetraploid hybrid and the three sexual hybrids show an intermediate essential oil profile with respect to those of both parents. The contribution of ‘Femminello’ lemon parent is in all cases predominant in the production of the volatile profiles of the new hybrids; however, a different behavior in the peel essential accumulation between the allotetrapolid hybrid and the three hybrids is observed.     

Aroma Impact Compounds in Three Citrus Oils: Cross-matching Test and Correspondence Analysis Approach

ABSTRACT Twenty‐three odor chemicals from 3 Citrus essential oils (lemon, Valencia orange, and Citrus sudachi) were selected as the potent character‐impact compounds on the basis of their limited odor unit values, and then every chemical was cross‐matched by sensory test to the 3 oils to attribute each aroma character to 1 of the 3 Citrus oils. The matching‐frequency data (ratio data) obtained was subjected to correspondence analysis and graphed on a diagram. Consequently, it was found that the aroma character of lemon oil was mainly represented by citral, with a high matching frequency of 0.89 (59 counts out of 66 trials, x²_o= 93.36). The orange character consisted mostly of linalool and nonanal. α, β‐Pinene, α‐sinensal and myrcene were related to the aroma of C. sudachi oil. The application of the cross‐matching test and correspondence analysis in the characterization of food aromas has never been reported in the literature to date, and the validity of these methods was successfully demonstrated by our study.     

Enzymic peeling of Indian grapefruit (Citrus paradisi)

The tough nature of grapefruit (Citrus paradisi) peel and its close adherence to the inner fruit sections limit the industrial processing of grapefruit. Two commercial peeling enzymes coded as ‘Brand A’ and ‘Brand B’ were studied for enzymic peeling of Indian grapefruit by vacuum infusion. The peeling process was optimised with respect to process parameters such as scalding time, enzyme concentration, vacuum infusion time and incubation time. © 2001 Society of Chemical Industry     

Comparison of cell wall metabolism in the pulp of three cultivars of ‘Nanfeng’ tangerine differing in mastication trait

BACKGROUND: Like sweet orange (Citrus sinensis), tangerine (Citrus reticulata) is another citrus crop grown widely throughout the world. However, whether it shares a common mechanism with sweet orange in forming a given mastication trait is still unclear. In this study, three ‘Nanfeng’ tangerine cultivars, ‘Yangxiao‐26’ (‘YX‐26’) with inferior mastication trait, elite ‘YX‐26’ with moderate mastication trait and ‘Miguang’ (‘MG’) with superior mastication trait, were selected to investigate the formation mechanism of mastication trait. RESULTS: ‘MG’ had the lowest contents of total pectin, protopectin and lignin and the highest gene expression levels of citrus polygalacturonase (PG) and pectin methylesterase (PME) at the end of fruit ripening, whereas ‘YX‐26’ had the lowest water‐soluble pectin (WSP) content, the highest lignin content and the lowest PG and PME expression levels. The contents of cellulose and hemicellulose were similar among the three tangerines. CONCLUSION: The fruit mastication trait of C. reticulata was determined by the proportions of WSP and protopectin as well as lignin content, not by cellulose and hemicellulose contents. Pectin content could be a major contribution to the feeling of mastication trait, while PG and PME exhibited an important role in forming a given mastication trait according to the present results as well as previous results for C. sinensis. Copyright © 2011 Society of Chemical Industry     

Comparative study on the antioxidant capacity and cholinesterase inhibitory activity of Citrus aurantifolia Swingle, C. aurantium L., and C. bergamia Risso and Poit. peel essential oils

Abstract: The interest in medicinal plant research and in the aroma‐therapeutic effects of essential oils in humans has increased in recent years, especially for the treatment of pathologies of relevant social impact such as Alzheimer's disease. The present study was taken up to evaluate the antioxidant capacity and the acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activity of the peel essential oils from three Citrus species, C. aurantifolia Swingle, C. aurantium L., and C. bergamia Risso & Poit. Essential oils were analyzed by GC and GC‐MS and they contain mainly limonene, α‐pinene, β‐pinene, γ‐terpinene, and linalyl acetate. C. aurantifolia oil showed the highest radical scavenging activity on ABTS assay (IC₅₀ value of 19.6 μg/mL), while C. bergamia exhibited a good antioxidant activity evaluated by the β‐carotene bleaching test (IC₅₀= 42.6 μg/mL after 60 min of incubation). C. aurantifolia inhibited more selectively AChE. Obtained data suggest a potential use of Citrus oils as a valuable new flavor with functional properties for food or nutraceutical products with particular relevance to supplements for the elderly. Practical Application: The demonstrated antioxidant activity and procholinesterase properties of Citrus essential oils suggested their use as a new potential source of natural antioxidant to added as extra‐nutrient for using in food industries as a valuable new flavor with functional properties for food or nutraceutical products with particular relevance to supplements for the elderly.     

Total,cumulative fast-kinetics and cumulative slow-kinetics antiradical activities of juices from clementine (<Emphasis Type="Italic">Citrus clementina</Emphasis>), clementine-hybrids and satsuma (<Emphasis Type="Italic">Citrus unshiu</Emphasis>) cultivars and their utility as discriminant variables

Mandarin juices from three pure clementine (Citrus clementina Hort. ex Tan.) cultivars: Clemenules, Hernandine and Marisol, two clementine-hybrid cultivars: Nova (clementine×tangelo Orlando) and Fortune (clementine× mandarin Dancy), one mandarin-hybrid cultivar: Ortanique (mandarin×orange) and one satsuma (Citrus unshiu Marc) cultivar: Clauselline have been analysed for determination of total, cumulative fast-kinetics and cumulative slow-kinetics antiradical activities. Total antiradical activity followed the order: pure clementine and Nova> Ortanique>Fortune and Clauselline. Cumulative fast-kinetics antiradical activity was the major contributor to total antiradical activity, accounting for about 87% as average. Ascorbic acid content was the major contributor to cumulative fast-kinetics antiradical activity, accounting for about 93.5% as average. A weak correlation (r ²=0.151) between total flavanone-7-O-glycosides (FGs, Narirutin, Hesperidin and Didymin) content and cumulative slow-kinetics antiradical activity was observed. However, ascorbic acid and total FGs contents showed a significant negative correlation (r ²=0.658). By using the cumulative fast-kinetics and slow-kinetics antiradical activities as variables, all the assayed juices were significantly discriminated (<0.05) by statistical multivariate discriminant analysis.     

Identification of Campania Citrus Limon L. by Random Amplified Polymorphic DNA Markers

Abstract

Genotypes of 10 lemon (Citrus limon L.) cultivars of the Campania region (Southern Italy) have been studied by using Random Amplified Polymorphic DNA (RAPD) markers with 44 arbitrary 10-mer primers. Some of the studied cultivars (Sorrento, Procida, Amalfi, and Gloria d’Amalfi) have been successfully distinguished by their band patterns using five out of the 44 selected primers, confirming that RAPD technology provides a useful tool to identify specific cultivars.     

Comparative GC/MS analysis of essential oils extracted by 3 methods from the bud of Citrus aurantium L. var. amara Engl

A comparative study of steam distillation extraction (SDE), reflux extraction (RE), and ultrasound-assisted extraction (USE) was conducted for the extraction of essential oils from the bud of Citrus aurantium L. var. amara Engl. Each method was evaluated in terms of qualitative and quantitative composition of the isolated essential oil by gas chromatography/mass spectrometry (GC/MS). The extract yields of essential oil were 0.16%, 2.18%, and 2.34%, respectively. A total of 82 compounds were identified by GC/MS. The main components obtained by SDE were terpinen-4-ol (20.98%), dipentene (11.67%), terpinene (9.24%), those by RE were palmitic acid (20.61%), 2-chloroethyl linoleate (14.54%), tetracosane (12.26%), and α-linolenic acid (11.24%), and those by USE were tetracosane (11.32%), heneicosane (11.06%), and palmitic acid (8.76%). Comparative analysis indicated that SDE was favorable for the extraction of monoterpene hydrocarbons, sesquiterpene hydrocarbons, alcohols, and carbonyl compounds, RE and USE had certain advantages in the extraction of aliphatic saturated hydrocarbons, organic acids, and esters. It is concluded that different extraction methods may lead to different yields of essential oils; the choice of appropriate method is very important to obtain more desired components with higher physiological activities. PRACTICAL APPLICATION: C. aurantium oils from different plant parts have great economic, medicinal, and nutritional values because of their wide-spectrum biological activities. The essential oil from C. aurantium L. var amara is one of the best C. aurantium oils. The data presented in this article will help us understand the relationship between essential oils and its extraction methods and know more about the aromatic components of Citrus aurantium bud. The methods established in this study will provide useful reference information for further studies, and offer essential oil industries with helpful guidance in practice.     

Characterisation of sour orange (Citrus aurantium) cultivars

Twenty-one cultivars of sour orange (Citrus aurantium L) and relatives selected in different areas of Spain were studied. Morphological determinations were carried out both in leaves and in fruits, including leaf size and area, number of oil glands, petiole length, fruit weight, number of seeds and others. Biochemical analysis included electrophoretic separations of proteins from leaves and fruit rind as well as peroxidases and esterases from some of the organs. Also chromatographic separations of rind oils were carried out in mature fruits. Quantitative and qualitative differences were detected for some of the cultivars. Enzyme differences were found to be adequate for distinction at the specific level. Two of the cultivars, ‘Bergamot’ and ‘Amargo clementino’, segregate from the main group, which indicates their belonging to a different species or to a hybrid. The validity of the present determinations for distinction and characterisation of material to be included in a citrus germplasm bank is discussed.     

Variation in the volatile terpenoids of two industrially important basil (Ocimum basilicum L.) cultivars during plant ontogeny in two different cropping seasons from India

BACKGROUND: Two Ocimum basilicum cultivars, ‘Vikarsudha’ and ‘CIM‐Saumya’, grown in the Kumaon region of western Himalaya were evaluated for their essential oil yield and composition at different stages of plant growth during two distinct cropping seasons (spring–summer and rain–autumn). RESULTS: The highest yield of essential oil was obtained at full bloom stage in both cultivars in both cropping seasons. The essential oils obtained from different stages in two cropping seasons were analysed by capillary gas chromatography with flame ionisation detection, and gas chromatography–mass spectrometry. The major component of cultivar ‘Vikarsudha’ was methyl chavicol (84.3–94.3%), while for cultivar ‘CIM‐Saumya’ the main components were methyl chavicol (62.5–77.6%) and linalool (14.4–34.1%). CONCLUSION: This study clearly indicated that cultivar, cropping season, plant ontogeny and plant part had significant effects on the yield and quality of the essential oil of O. basilicum. Further, the amount of methyl chavicol in the cultivars grown in this region was higher than in cultivars from other parts of India. Copyright © 2011 Society of Chemical Industry     

Identification of flavanones from peel of Citrus changshan-huyou Y. B. Chang, by HPLC–MS and NMR

High-performance liquid chromatography coupled with a UV photodiode-array detector and a mass spectrometer (HPLC–MS) was used to analyze the constituents of an extract of Citrus changshan-huyou Y. B. Chang peel. Structures of two flavanones were identified based on their abundant [M+H]⁺ ions, UV spectra, and ¹HNMR and ¹³CNMR spectrometer as 5,4′-dihydroxy flavanone-7-O-α-glucoside (naringenin-7-O-α-glucoside) and 5,3′-dihydroxy-4′-methoxy flavanone-7-O-α-glucoside (hesperetin-7-O-α-glucoside). The two flavanones were first identified from peel of Citrus changshan-huyou Y. B. Chang.     

大型罗勒和柚子精油的成分分析及其抗氧化性

采用气相色谱-质谱(GC-MS)联用法对大型罗勒精油和柚子精油的化学成分进行分析,并采用DPPH自由基(DPPH·)清除法、ABTS自由基阳离子(ABTS⁺·)清除法对精油及其主要单体的抗氧化性能进行了研究。大型罗勒精油鉴定出46个化学成分,占总含量的84.07%,其主要成分为香叶醛(14.20%)、β-石竹烯氧化物(10.97%)、香橙醛(10.38%)和β-石竹烯(4.09%);柚子精油鉴定出48个化学成分,占总含量的92.24%,其主要成分为柠檬烯(43.88%)、石竹烯(22.09%)、葎草烯(4.57%)和γ-松油烯(4.41%)。结果表明,大型罗勒精油和柚子精油对DPPH·和ABTS⁺·均具有清除活性,其中大型罗勒精油和柚子精油清除DPPH·的IC₅₀值分别为3.96 mg/mL和23.22 mg/mL;清除ABTS⁺·的IC₅₀值分别为1.61 mg/mL和2.30 mg/mL。由此可知,大型罗勒精油和柚子精油可以作为一种较为安全的天然抗氧化物来源。     

Effect of pre‐harvest salicylic acid spray treatment on post‐harvest antioxidant in the pulp and peel of ‘Cara cara’ navel orange (Citrus sinenisis L. Osbeck)

BACKGROUND: Exogenous salicylic acid (SA) pretreatment could change the antioxidant system and maintain the nutritional value of fruits and vegetables, which have a higher ability to withstand oxidation injuries. However, the relationship between a pre‐harvest SA spray and post‐harvest antioxidant compounds in fruit remains unknown. RESULTS: The post‐harvest behaviour of antioxidant compounds in ‘Cara cara’ navel orange (Citrus sinenisis L. Osbeck) fruit was investigated in relation to the pre‐harvest SA applications. Pre‐harvest SA treatment significantly increased the content of carotenoids (lycopene and α‐carotene), ascorbic acid, glutathione, total phenolics, and total flavonoids in the pulp and peel during storage. Furthermore, the values of these antioxidant compounds were high in the fruit treated with high SA concentrations (1.0 and 2.0 mmol L^?1). High antioxidant activity was also observed in the SA pre‐harvest treated fruit when compared with the control. The positive relationships were found between the antioxidant activity and the content of these active compounds. CONCLUSION: These results indicated that SA could maintain fruit antioxidant activity and nutrition which was shown by the increase in content of antioxidant compounds and suggested that pre‐harvest treatment with SA promised a novel technology, which was a substitute for the perplexing programme control of post‐harvest nutrition in fruit. Copyright © 2007 Society of Chemical Industry     

Citrus Tachibana Leaf Extract Mitigates Symptoms of Food Allergy by Inhibiting Th2‐Associated Responses

Although the incidence of food allergy continues to rise, there have been no effective therapeutic strategies. Citrus fruits contain a number of bioactive flavonoids with immune‐regulatory functions. The objective of this study was to determine whether Citrus tachibana (fruit body with peel, leaves, and branch) can protect against the development of food allergy and the mechanism behind it, and to identify the active compound(s) responsible. We found that C. tachibana leaf extract (CLE) mitigated ovalbumin (OVA)‐induced food allergy symptoms including increased rectal temperature, diarrhea, and anaphylaxis. This mitigation was likely due to CLE‐mediated decreases in cytokine release from T‐helper 2 cells (Th2 cells) in mesenteric lymph nodes. Moreover, higher levels of CLE attenuated systemic Th2 cell–mediated responses in mouse splenocytes sensitized with OVA+Alum. This was evidenced by CLE‐mediated reductions in Th2 cytokine release, including interleukin (IL)‐4, IL‐5, and IL‐13, but not the Th1 cytokines IL‐12 and interferon (IFN)‐γ, which was attributable to decreased gene expression levels. We also identified kaempferol as the most potent compound for reducing Th2‐associated responses in splenocytes. The findings of this study suggest that CLE suppresses Th2‐cell–mediated immune responses, contributing to alleviation of food allergy symptoms, and that kaempferol is a flavonoid with potential antiallergenic activity that targets Th2 cell–induced responses.     

Juice components and antioxidant capacity of four Tunisian Citrus varieties

BACKGROUND: Juices from four Citrus species of Tunisia were investigated mainly for quality parameters and antioxidant capacity. RESULTS: Citrus reticulata (mandarin) juice had the highest content of total flavonoids (85.33 mg CE L^?1). The latter also occurred in high quantity (82.01 mg CE L^?1) in Citrus lemon (lemon) juice which was also marked by its richness in total aroma (70.16 µg mL^?1) and in total fatty acids (48.10 µg mL^?1). Mandarin and lemon juices had the highest antioxidant activity, as determined b the β‐carotene bleaching assay (26.67% and 22.67%, respectively). Citrus aurantium (bitter orange) juice was characterised by the highest content of total polyphenols (784.67 mg GAE L^?1) and by the greatest inhibition of DPPH (96.10%). Citrus sinensis (blood orange) juice was only marked by the high quantity of ascorbic acid (36.90 mg mL^?1). GC/MS analysis of juice aroma showed the predominance of limonene (48.85–69.59%) in mandarin and in bitter and blood oranges, but of camphene (89.05%) in lemon. GC analysis of juice fatty acids revealed their richness in oleic acid (23.13–39.52%). HPLC analysis of juice phenolics indicated the predominance of phenolic acids (73.13–86.40%). CONCLUSION: The Citrus species used in this study were considered valuable varieties from the point of view of antioxidant capacity and nutrition. Copyright © 2010 Society of Chemical Industry     

Effect of drying methods on volatile compounds,fatty acids and antioxidant property of Thai kaffir lime (Citrus hystrix D.C.)

This study investigated the changes in colour, volatile compounds, fatty acids, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity of kaffir lime leaves (makrud in Thai) Citrus hystrix D.C. after three drying treatments, namely hot‐air (HA) drying, low relative humidity (LRH) air drying and far‐infrared radiation (FIR) drying. Overall, when compared with fresh leaves, a slight decrease in L* values of the three dried samples was observed. TPC, TFC and ferric‐reducing/antioxidant power (FRAP) values were increased by LRH and FIR drying (LRH: 39%, 43% and 28%; FIR: 62%, 39% and 39%), while HA drying decreased TPC, TFC and FRAP values (28%, 21% and 1%), compared with fresh leaves. The main volatile compounds in fresh leaves were citronellal, followed by linalool and viridiflorol. Drying brought about an increase in the concentrations of volatile components, such as citronellal with HA, LRH and FIR drying (79%, 83% and 64%, respectively), compared with the results for fresh leaves (56%). LRH and HA drying increased essential fatty acid alpha‐linolenic acid (ALA, 18:3n‐3), while linoleic acid (LA, 18:2n‐6) was increased by FIR drying. The present study has provided useful information for the industrial use of dried kaffir lime production.     

佛手挥发油不同提取方法的比较研究

应用冷榨法、水蒸汽蒸馏法、有机溶剂回流法、同步蒸馏-萃取法提取佛手油,并比较了不同提取方法的佛手油得率。采用GC和GC-MS分析方法分析了这几种提取方法对佛手油化学成分的影响。结果表明,水蒸汽蒸馏法与其它方法相比,具有提取快速完全、节省时间、成本低,所提取的有效成分含量较高等优点。     

贮藏温度对耐贮性不同的柑橘品种果皮蜡质含量及其化学组成的影响

为探究果皮蜡质与柑橘果实耐贮性的关系，以广东西江流域著名特产柑橘‘贡柑’（耐贮性较强）、‘砂糖橘’（耐贮性差）果实为试材，采收后装入塑料薄膜保鲜袋中分别在自然室温（（14.2±2.8）℃）和冷库温度（（6.5±0.5）℃）下贮藏90 d，定期检测果实质量损失率、腐烂率、果皮表面结构和蜡质含量及化学组成。结果表明，在不同温度下贮藏，两种柑橘质量损失率和腐烂率显著增加（P＜0.05），表面结构发生改变，果皮蜡质总含量及主要组分（长链脂肪醛、长链脂肪酸、长链脂肪烃、长链脂肪伯醇）含量均显著降低（P＜0.05），冷藏相对于室温贮藏会抑制这些变化，起到关键的保鲜作用。质量损失率、腐烂率均与果皮蜡质总含量及4 类主要组分含量均呈极显著负相关（P＜0.01）；贮藏过程中果皮蜡质不同组分含量的降低幅度存在差异，其中耐贮性较强的‘贡柑’长链脂肪酸含量降幅最大、长链脂肪伯醇含量降幅最小，耐贮性差的‘砂糖橘’长链脂肪伯醇含量降幅最大、长链脂肪酸含量降幅最小；小分子质量的支链烷烃、烯烃和烯醛对贮藏温度的响应更敏感。说明两种柑橘果实的耐贮性与果皮蜡质含量和组分有密切关系。     

A comparison of the peel oil components of Australian native lime (Microcitrus australe) and Mexican lime (Citrus aurantifolia Swingle)

The essential oil components extracted from the pericarp layer of two varieties of lime fruit, viz. Mexican lime (Citrus aurantifolia Swingle) and an Australian native lime (Microcitrus australe) have been analysed by gas chromatography/mass spectrometry. Thirty‐three components were identified in M australe and 34 in C aurantifolia. The compound types comprised monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpenes and coumarins. For the more volatile monoterpenoid compounds, the major component was limonene, with significant amounts of γ‐terpinene, β‐pinene, geranial, neral, neryl acetate and geranyl acetate. From an examination of the nature and contents of individual components, there was no indication that any one compound might be responsible for the predominant aroma impact. The possible contribution to aroma differences due to quantitative differences in the amounts of these components is discussed. However, sensory evaluation indicated that there was little or no difference between the aromas of the two oils. Copyright © 2004 Society of Chemical Industry